The Coal Question, Revisited

This is a guest post by Professor Dave Rutledge (DaveR), of the California Institute of Technology (Caltech).

In the summer of 2007, Professor Kyle Saunders (Professor Goose) invited me to do a guest post for The Oil Drum. This post was "The Coal Question and Climate Change." In the post, Hubbert linearization was applied to make a regional analysis of world coal production. The estimate for long-term production, including both cumulative production and all future production, amounted to 724Gt. Many people, including Dave Summers (Heading Out) and Euan Mearns, made helpful critical comments on the post, particularly concerning British coal production. Overall, I was encouraged by the response. The Oil Drum is a great place to try out new ideas.

I now have a paper "Estimating Long-Term World Coal Production with Logit and Probit Transforms" that is in press at the International Journal of Coal Geology. People who are interested can download a pdf preprint at my web site. There is also an Excel workbook with the data for the paper at the site. The paper makes several changes from the original post. At that time, I did not have complete production data, and I was relying on cumulative production totals from reports by the BGR, the German resources agency. These turned out to be incomplete. However, over time, I was able to fill in the gaps in the production histories. Steve Mohr at the University of Newcastle in Australia gave wonderful help, and Nadia Lapusta, a Ukranian engineering professor at Caltech, located Russian language histories for the different Soviet republics. I was able to fill out the early American state production numbers from Harold Eavenson's 1942 book, The First Century and a Quarter of the American Coal Industry.

In addition, I became dissatisfied with Hubbert linearization. Hubbert linearization involves annual production directly, and this gives larger fluctuations in the estimates than an approach based on cumulative production. This is a particular problem for coal, which shows large production drops in strike years. Hubbert linearization assigns weak weight to the later years in the production cycle, and this means one often has to make a judgment call about throwing out a large number of the earlier points, because their influence is too strong. Also, Hubbert linearization is based on the logistic function, and a cumulative normal is a better fit for some regions. In the new paper, the logit transform is used to linearize the cumulative production history for the logistic fits and the probit transform for the cumulative normal fits. One way to understand how these linearizing transforms work is to think in terms of an exhaustion function, defined in the paper as the fraction of the long-term production that has already been produced. The exhaustion starts off at zero, and then monotonically increases, eventually reaching unity when the last mine shuts down. It has the same properties as a cumulative density function in statistics. From this perspective the probit transform is the inverse of the standard cumulative normal function, and the logit transform is the corresponding inverse function for the logistic distribution. The statistical quantity r2 (correlation coefficient squared) is maximized to find the long-term production estimate. This is a simple one-parameter fit, and it takes about one second in Excel. There are two regions where production is developing that do not give a maximum value for r2, South Asia and Latin America. For these regions, I used the reserves as an estimate for future production, even though the experience with the mature regions indicates that these numbers are likely to be too high.

Finally, in my original post, I had considered Montana as a separate region. Montana has enormous reserves, 68Gt at year-end 2008, but only modest annual production, 36Mt in 2009. I had used Montana's reserves as an estimate for its future production. After studying the USGS assessments for the area I came around to the view that this was not appropriate. The main production in Montana is from the Powder River Basin (PRB), and it appears that Wyoming drew much the better hand in the PRB. I believe that the differences in PRB production for Wyoming and Montana represent geology at least as much as any other factors. For more discussion, see "Potential for Coal-to-Liquids Conversion in the U.S.-Resource Base," by Gregory Croft and Tad Patzek, Natural Resources Research, volume 18, pp. 173-180. Montana does follow the same two-cycle pattern that other Western US production does, and I believe that Montana production is appropriately captured in a curve fit for the Western states.

Recently, Dave Summers addressed the topic of future British coal production in his Oil Drum post, "Future Coal Supplies - More, Not Less!" The British production experience parallels that of the three other mature regions in my paper, Pennsylvania anthracite, France and Belgium, and Japan and South Korea. Production in each of these regions is less than 10% of the peak production. Also, in each region, the early reserves were much larger than the production that followed. On average, the early reserves plus contemporary cumulative production have been four times the current cumulative production. On the other hand, in each case, the curve fits gave appropriate estimates for the long-term production, by 1900 for the UK, Pennsylvania anthracite, and France and Belgium, and by 1950 for Japan and South Korea. This is shown in the figure for British production.

Comparison between the reserves in the international surveys and the historical long-term production estimates for British coal. The range in the historical estimates since 1900 has been 26.8-30.0Gt. The current cumulative production is 27.4Gt, while the producton in 2009 was only 18Mt.

At the time of my original post, there were seven collieries with producing longwall faces in the UK. Since then, two have closed, Tower, and Welbeck. Five remain: Daw Mill, Hatfield, Kellingley, Maltby, and Thoresby. In addition, maintenance is being done on Harworth Colliery so that it could be brought back into production at some point. For comparison, William Ashworth's History of the British Coal Industry states that there were 803 producing faces in 1973. For completeness, it should be noted that there are also small underground mines that together contribute 1% of British underground production. In addition, there are surface mines. Surface mining in the UK started during the Second World War and peaked in 1991. The decline in surface production has been slower than for underground production, to the extent that by 2009 surface production was actually a third larger than underground production [3]. The largest coal company in Britain is UK Coal, which operates Daw Mill, Kellingley, Thoresby and Harworth. UK Coal's on-line financial reports indicate that its underground mining group has lost money ten years in a row, and that the company has debts of £250,000,000, twice its market capitalization. These mines are the last survivors out of thousands. As they run out of seams to work, they will close, one by one.

The new estimate for total world production, past and future, is 680Gt. This is 6% less than the earlier one in my original Oil Drum Post, primarily because the reserves for Montana no longer figure in the total. To get a feeling for the uncertainty, I check the stability of the estimate by making historical fits that use only the data available in an earlier year. The estimate for long-term production has varied in a range from 653-749Gt (14%) since 1995. I can make a comparison with Steve Mohr and Geoffrey Evans' [2] and Tad Patzek and Greg Croft's [3] recent estimates. Mohr and Evans use Hubbert linearization at the national level to get 702Gt, and Patzek and Croft use a multi-cycle analysis to get 630Gt. In addition, Patzek and Croft have possible contingencies of 70Gt for Siberia and 55Gt for Alaska. I view the three estimates as supporting each other, because they are calculated in different ways. My estimate is 58% of the current cumulative production plus current World Energy Council reserves, 1,163Gt. However, all the estimates for the long-term production, and the cumulative production plus reserves are completely different from what the IPCC (United Nations Intergovernmental Panel on Climate Change) assumes is available for production in its scenarios. The maximum cumulative production in an IPCC scenario through 2100 is about 3,500Gt. This actually understates the difference, because in this scenario, A1C AIM, production is still rising in 2100, implying substantial production after 2100.

The transform analysis also gives time parameters through a linear regression. These are expressed as the years of 10% and 90% exhaustion. The last region to reach 90% exhaustion is Russia, in 2101. For world production, the curve fits indicate 2070 as the 90% year. This gives a time frame for thinking about alternatives. The time parameters have an additional element of uncertainty compared with the estimates for long-term production, because in some regions there have been shocks that are associated with a change in the pace of production. The most important example was the collapse of the Soviet Union, when production in Russia and Eastern Europe slowed. For this reason, it would be appropriate to view the year 2070 as a current estimate, subject to future shocks.


[1] British coal production statistics are available at the web sites of the Coal Authority and the Department of Energy and Climate Change

[2] Mohr, S.H. and Evans, G.H., 2009, ìForecasting coal production until 2100, Fuel, Vol. 88, pp. 2059-2067.

[3] Patzek, T. and Croft, G., 2010, "A global coal production forecast with multi-Hubbert cycle analysis," Energy, Vol. 35, pp. 3109-3122.

Here's my basic problem with your argument: How can you know that the amount of extractable coal will not go up substantially at higher price points?

Take a doubling of the price of coal. How many coal fields become economically feasible to mine at double the price? Is there some way to get at that?

Hi FuturePundit,

Thanks for your comment. The Germans have done an interesting experiment in the Ruhr by subsidizing the production of bituminous coal to the level of four times the world price for decades. This is as close as we get in the real world to "technically recoverable coal." The production has been crashing at 8% per year (like British underground production), and will likely end in the next decade. Like the UK, Germany evaluated its Ruhr reserves as over 100Gt a hundred years ago. The total production will be around 10Gt.

In the post, I mentioned UK Coal's debt problems. In the paper, a calculation is done that indicates that the price UK Coal is getting now, inflation adjusted, is more than twice the 1859 price. Also, I became aware over the weekend that Powerfuel, the parent company for Hatfield Colliery, is in administration (roughly equivalent to bankruptcy proceedings in the US), and the mine is for sale. The mine is a hundred years old and has shut down twice before. It is working its last seam and needs £30,000,000 in improvements. Anyone interested?


The Germans have done an interesting experiment in the Ruhr by subsidizing the production of bituminous coal to the level of four times the world price for decades. This is as close as we get in the real world to "technically recoverable coal."

Of course that is pretty much like looking at a single coal or oil field and finding just how much coal or oil can be squeezed out of it at four times the current market price. The 'Ruhr experiment' would seem to show very little about how much resource becomes available (as the real price quadruples) in areas that are currently just too distant from markets to be producing economically now.

Any analysis of $12 a barrel oil in decades not so long past would not have vertically distant deep water oil making near the contribution to the supply that it now makes.

Just looked at your 'More,Not Less!' post so its obvious we agree on that point. Since I want to see your spreadsheet you've actually forced my hand and I'm finally downloading an Excel viewer, thanks ?- ) I was too cheap to actually put the excel on this machine.

Of course a huge amount, probably most, of the the world's northern coal is not even classified as a resource yet. That coal is merely a hypothetical resource. Its not hypothetical because it may or may not be in the ground but rather because it may or may not ever be economical to mine it. The size of the US hypothetical resource dwarfs the BP stated US resource size--I'm guessing the same is true for the other two huge countries that spill into the arctic, Russia and Canada.

See my post below for a map of the minimum ice extant in 2010--shipping lanes to the north's resources look to becoming a near term reality. I know you love coal but I sure hope we don't burn near what is out there.

I read "Estimating Long-Term World Coal Production with Logit and Probit Transforms" earlier and think the Logit and Probit transform approach is an advancement over Hubbert Linearization. It looks similar to what Sam Foucher did with the Hybrid Shock Model. Although no doubt better than HL, which both Rapier and I have shown dissatisfaction with, I would prefer that we think about depletion and a host of other problems through maximum entropy and related probability techniques.

So this is not at all a bash at Prof. Rutledge, but just a chance to announce that I have compiled most of my blog postings and edited them to fit into a manuscript format. Whether it will make it easier for "everyone" to follow my arguments, I kind of doubt it. But having the narrative formatted in math markup, captioned figures, full index, references, links, and footnotes should make it easier for people that are serious about the topic.

Should have the first draft out early January as a PDF.

To be published as a book?

For now just a big 2 volume PDF, over 700 pages. The first volume titled Decline and the second volume Renewal.

Congratulations for the this milestone Web. I look forward for it, though I doubt I'll be able to digest it timely.

And sorry for not being as helpful as I wish I could. Best.

Thanks. The hardest part is knowing when to stop.

Anecdotal evidence supports the view that we are within sight of Peak Coal. In the picturesque Hunter Valley of New South Wales wealthy business people have set up thoroughbred horse farms. Lately coal miners want to dig large pits right next door. Now even the business types are questioning the scramble for coal.

Another telltale sign in Australia is that Chinese and Indian interests are buying coal mines. For now that coal goes into the system but perhaps later it could be direct export. The Australian government seems to have its head in the sand or perhaps coal dust. We are the OECD's biggest per capita CO2 emitter (~20t a year) and the biggest coal exporter (250-300 Mt a year) yet we lecture other countries at the climate conferences. To Peak Coal I say bring it on.

The one line message I get from this article would be this -

Three peer reviewed studies have concluded that total world coal production to 2100 will be 20% or less of the figure assumed by the IPCC.

see further my comment 6:18 am below.

The message you get from the article is erroneous. The B1 scenario for instance has coal productions that encompass the estimates from Dave, but he fails to mention that. IPCC has a wide range of scenarios, and makes no predictions about which the future will look most like! That is up to us to choose...

With the B2 scenario follows a calculated 2 centigrades increase in temperature 2100 compared to 2000.

Boof is right, kinda. The IPCC scenarios are demand led, and all based on the same large reserve figures. The B1 scenario is just one where due to socio-economic factors we choose not to use as much fossil fuel.

The peer reviewed studies aren't addressing the IPCC's demand led scenarios, they are addressing the common large reserve figure. The studies suggest this reserve figure (and the production rates it supports) is considerably less than the IPCC assume.

ok fair enough, I dont know the reserve estimate in B1.

BUT Boof assumed "production" (not reserves), so he takes in the wrong spirit from the main post in any case. B1 has coal production which is as Dave states from his analysis, less than 700 Gt.

Agreed. Unfortunately, Rutledge continues to tie his estimates to IPCC reports that are now based on science even further out of date. Kjell Aleklett continues to make the same error.

What both fail to acknowledge is what you cite above: they are scenarios, not predictions. Rutledge, at least, being a scientist, should have no problem understanding this except that he is not a climate scientist, but studies geology, if I recall.

He has at least chosen to merely mention the IPCC rather than go on at any length. I believe this to be a wise course of action on his part, for he leaves us to guess at his motivations and retain plausible deniability. However, we cannot let this pass without comment.

In addition to the error contained in mentioning but the worst case scenarios, thus creating the incorrect impression that the IPCC was somehow "wrong" and their conclusions improbable if not impossible, Rutledge fails to acknowledge that what the IPCC said three years ago is actually now 5 - 30 years old. The massive amount of research and significant new findings make any conclusions of the IPCC IV nearly irrelevant. If Rutledge wishes his work to be taken seriously, he must take a different approach to coal reserves and the IPCC.

Avoiding this problem is simple: 1. Use his estimates of coal reserves to analyze the full range of IPCC IV scenarios; 2. acknowledge research since 2005, such as and, for example.

The basic logic that we will reach 2C above pre-industrial with what is already in the pipeline, and that both sub-sea and tundra-based clathrates are already degassing at increasing rates should cause Rutledge and others to hedge their bets. The logic is simple: if the worst case scenario (melting clathrates, melting glaciers, melting Greenland, melting WAIS, massively reduced Arctic sea ice 40% reductions in plankton, ocean acidification, etc. ) is already being observed, and it is, then coal reserves are irrelevant because any additional emissions are much too dangerous to allow. In fact, more and more climate scientists are saying 3 and 4C is already inevitable. A finding that supports this is the one by Hansen, et al., that Greenland has previously melted at a 400 - 600 ppm range. That is, we are already in a range that can raise sea levels 7 meters.

In the past, the explanation that if the IPCC hasn't reported on it yet, it's not official, is erroneous and rejected outright. The IPCC simply collates the science done up to a given point in time and offers a consensus opinion on what may lie ahead, it does no science. The science is what it is and is not changed in any way via the IPCC reporting process.

That this new data seemingly does nothing to give pause to Rutledge and Aleklett is disturbing, to say the least. Rutledge, at least, is a scientist, after all.

I look forward to an explanation of Rutledge's thinking on ignoring climate science of the past five years and his focus on only one of several scenarios.

I encourage him strongly to contact Katey Walter Anthony or her colleagues involved in Arctic research if he wishes to maintain a balanced view of the relationship of carbon to climate:

Water and Environmental Research Center
525 Duckering Building
University of Alaska Fairbanks
Fairbanks, Alaska 99775
(907) 474-6095
(907) 474-6095

Happy digging.


"but studies geology"

Don't investigate much before you write, do you?

"for he leaves us to guess at his motivations and retain plausible deniability"

New to The Oil Drum? Stick around, you might learn some politeness.


But Cmon thats a completely dissatisfying answer. Ok the two sentences you choose two mention was the two weakest in the text above,
but they are not completely hostile neither. It is poor that you choose that easy way out, instead of explaining what you really want, Dave.

Where is the problem with the B scenarios or the new 3 w/m2 scenario?


Please acknowledge in my post above that I reference your earlier work. No, I am not new to the oil drum. I've no doubt I read it more often than you and investigate all areas of the current crisis, save energy production explicitly, more thoroughly than you do.

I see no impolite comments above. Segeltemp has pointed out problems with your analysis, as have I. Your post here shows no evolution of your thoughts over what you produced in '07 and no evidence you have taken any critiques to heart.

So you're not a geologist. You also are not a climate scientist. My points must all be invalid, then.

Contact Katey. She has responded to my e-mails in the past, I'm sure she'll respond to yours. It is an important issue, and it is important that you, Kjell and others come to understand climate because you are, imo, grossly misinforming the public on this issue.

The logic is simple: the changes so far exceed worst case scenarios, but are occurring at CO2 levels far below those eventual levels. The A1 scenario is irrelevant. We are 90 years ahead of schedule.

Contact Katey.


You should actually address the issues raised, not add your own flame. Is the official Oildrum policy to ignore climate science. We are now hovering close to 400 ppm....and rapidly climbing.

Two comments on the state of UK Coal reserves and the financial health of UK Coal plc.

Some surface mine reserves in the UK have been or are proposed to be sterilised by Government action. The Governments of Scotland and Wales have already introduced a 500 metre buffer zone between areas of settlement and surface / opencast mine sites. When this proposal was made for Wales coal producers claimed that it would sterilise a significant proportion of known coal reserves:

" Members expressed there concerns that the 500 metre boundary proposed in the
consultation would lead to nearly two thirds of the coal reserves in Wales being
sterilised and that the remaining third had either been worked or was uneconomical.
Members said that the introduction of wind farms was also causing issues for the
sterilisation of coal reserves. Members felt that the impact of this sterilisation would
close the surface mining industry in Wales. Members noted that this was likely to
form a precedent which would be followed by England and Scotland."

(8th Meeting of the UK Coal Forum available @ )

I do not have a reference to show what the impact of such a measure has been on Scottish coal reserves.

Now Andrew Bridgen MP has a Bill before Parliament to introduce similar legislation to cover England. First indications are that, if passed, this measure would reduce available English coal reserves by a further 200 - 500m tonnes of recoverable coal (see 'Visit to opencast sites test out buffer zone', The Journal 3/11/10 @

As yet I have no information on what proportion of known English / UK reserves this represents.

In addition, as possibly the original author of the cumulative deficit being carried by UK Coal plc in 'UK Coal: An Alternative Report' and the update 'Briefing Note C1 'UK Coal's Financial Situation' avaible from, just to bring UK Coal's debt figures up to date its last Interim Financial Staetment, October 2010 indicated that the level of debt had risen to £265m (See

Just to put the 200 - 500M tonnes estimate of England's recoverable coal (above) into perspective, because of rapidly declining home production, the UK, England with Scotland & Wales & N.Ireland, in recent years has imported as much as 50Mt a year for power generation and consumed up to 70Mt (albeit somewhat less than that since 2006). Coal's share of primary energy production in UK has declined from around 90% in 1950 to less than 20% since 1995.


You may be aware of this already but I'll post it anyway

I've just come across some 'official' information on the state of UK Coal reserves as at 2006. Then, the statutory legal body with the responsibility to safeguard coal reserves and promote their utilisation (as well as other functions), The Coal Authority gave evidence to the Government's 2006 Energy Review.

In it they gave three definitions of how to define coal reserves, 'coal in place' , 'recoverable reserves' and 'operating reserves'

After reviewing changes made to assessing the UK Coal's reserves dating back to 1977 the evidence presented to the Government was that there were then 86m tonnes of recoverable coal in deep mines which would be exhausted by 2020 if no further investment occurred. if investment was undertaken then 159m tonnes of recoverable coal which on present trends would be exhausted by 2035. The total opencast / strip mine reserves were put at 909mt in 1993 in the evidence.

The information is downloadable from

The (UK)Coal Authority web site address is:

Hi Steve,

Thank you for the link, which shows how the thoughts on reserves have evolved over time.


Dave, thanks for your reply to my comments,

I can now update the information about UK Coal reserves and answer my own question about the proportion of UK surface Mine reserves that my be sterilised if Andrew Bridgens 500m Buffer Zone Bill is successful. Below is the latest assessment of UK Coal Resources by the Coal Authority dated 4th March 2010 (personal communication)

Deep Mines (all categories of reserves) 2,552m tonnes

Surface Mines (all catagories of reserves) 869m tonnes

Total 3442m tonnes

English Surface Mine reserves, according to this analysis, totalled 516m tonnes.

If correct, this means, according to the news story in the Journal above, that Andrew Bridgen's Bill could sterilise between 250 - 500m tonnes of the English Surface Mine Reserves, or between 48 and nearly 97% of such reserves!!

The Bill is due for it's second reading in the UK'a House of Commons on 11th February 2011. In light of these figures it will be interesting to see what happens.

Hi Steve,

Thank you for the link to your report about the UK Coal losses. I should have referenced it. My error.


"....The main production in Montana is from the Powder River Basin (PRB), and it appears that Wyoming drew much the better hand in the PRB. I believe that the differences in PRB production for Wyoming and Montana represent geology at least as much as any other factors."

One significant factor in Montana coal production is the lack of access to local rail lines. During the late 1970's through the mid 1980's several new rail lines were built in the Wyoming's Powder River Basin to access this coal, most notably the Gillette to Orin line of the Burlington Northern railroad. Later the Union Pacific railroad built a connector to the PRB. In contrast, the state of Montana has had many rail lines removed during the late 1970's and early 1980's. As example a mine at Klein, MT has to truck the coal about 50 miles to a rail head near Billings since the rail line through Klein was abandoned in 1981. The coal mine shut down, then reopenned after the state rebuilt the highway for heavier trucks to haul the coal.

Unless the coal can be shipped almost entirely by rail, some of the US coal deposits may not be economical to mine, especially given the high cost of trucking due to fuel price increases. Besides, most states do not want the burden of heavy coal trucks destroying the highways, as they cannot they afford repairs with tax revenue shortfalls. And certainly the coal mine companies cannot afford to build new highways. So the coal may very well remain in the ground forever at numerous places in the US.

It may come down to abandoned railways being rebuilt as in "trails to rails". Anyway, Kunstler and others think railroads will regain their significance as a serious mode of transport for passengers and cargo once the era of cheap energy is behind us. I think it will soon become apparent that ripping up railroads and building more highways as they did in the 80's and 90's was a bad move.

There's little question that freight will move from trucks to rail. OTOH, passengers will mostly move to EVs.

Local freight, between the intermodal yards and the shipping points will stay truck. There are too many origins/destinations for freight to go back to rail without a huge investment to build out local railroad tracks.

Maybe time to start thinking about alternatives. One of the issues would be that areas are built up and there is no room for a line while tunnels are expensive. If it is freight only how about suspended monorails above roads. Individual units with electric pick up. They could be semi-autonomous to route to different points. If people object to no man on board then take a hint from the future of the aeroplane and leave space for a man and a dog.


I think that distribution of goods will become more efficient around two models.

On model is the parcel delivery model, where the customer orders over the web and one of the parcel delivery services optimizes transportation from the distribution center to the customer.

The other is the WalMart model, where the customer only drives to one store for all their shopping needs, and WalMart optimizes the transportation of a complete array of products to the store.

Between these, you can take a lot of truck miles out of retail distribution. You also achieve a lot of real estate and energy savings by getting rid of small inefficient retail establishments.

I agree. I really meant long-haul trucking.

Short haul trucking can electrify with little problem. Companies with large local delivery operations, like Staples, UPS and others, are moving to electric trucks (though they're still moving slowly):

"The trucks, which have a top speed of about 50 mph and can carry 16,000 pounds, cost about $30,000 more than a diesel, but Staples expects to recover that expense in 3.3 years because of the savings inherent in the electric models, Mr. Payette said."

I don't know where you live, but in Sweden rail takes 4% of cargo transport, and without massive investments, it is as high as it gets. Passenger transport is incrasing by the year, and we are already running the rail system at above maximum capacity. In Sweden,and most of Europe, rail will not carry most of the goods in the future. We don't have enough rail for that. I still maintain railroads are for moving people around.

1) in the US, the majority of freight goes by rail - the rail system is optimized for freight, and passengers take a distant 2nd priority. Freight capacity is fully utilized currently, but capacity could be expanded relatively easily by double tracking and adding more rolling stock.

2) in Europe, rail is aimed at passenger transport, and the majority of freight goes by truck - the rail system is optimized for passengers. A major barrier to expansion of rail freight is non-standardization of track, signals, etc.

According to Alan Drake (Alanfrombigeasy) there is a large potential for expansion of rail freight on the continent (France, Germany, Switzerland, etc). I'm not sure if he's addressed Sweden.

Large investments may be needed to expand rail, but you have to put those costs in perspective: how much will Europe spend on diesel for freight over the next 30 years? 2 Trillion Euros??

North America (the US, Canada, and Mexico) has an integrated freight railway system that carries almost half of the continent's freight. It is almost completely privately owned, and there are about 600 railway companies (although the seven Class I railways - five American and two Canadian - carry most of the freight), but they can interchange freight cars to get it freight anywhere in North America to anywhere else in North America.

There is a system of pooling freight cars that allows railways to borrow freight cars from other railways without asking for permission, and it is very effective in moving freight cars to where they are needed with no regard for who owns them. Many companies only own freight cars and have no locomotives or tracks of their own. They make money from the use of their freight cars. Other companies have locomotives and tracks, but not very many freight cars. They make money from moving freight cars for other companies.

One of the biggest advances has been the double-stacked container train, using intermodal containers to move cargo from the seaports to the destination cities, where they are loaded on trucks for final delivery. Clearances are sufficiently high in most of North America that they can put two containers on each railway car, and since the trains can have over 100 cars, they can move over 200 forty-foot (12 metre) containers per train. Often these containers are oversize (overlong and/or overhigh) because the clearances are large enough.

Using computerized scheduling they can move about 24 of these 200-container trains per hour in each direction over a single track, and if they double-track the line, they can move considerably more. In some places the railways are triple-tracked or quadruple tracked.

The only problem is that this system is incompatible with carrying passengers, so the freight railways do their best to discourage the use of passenger trains on their tracks. Their goal is to make money, not compete with the airlines.

That puts North American rail in a nutshell nicely RMG. I was aware the US and Canada linked freight rail seamlessly (US/Canada cooperation in general, is in my opinion, is unrivalled). I guess I should have known Mexico was part of the system as well, since some of the illegal traffic carried by rail does make the news from time to time.

Per chance do you have access to the numbers on cost per pound/mile of a double stacked container freight relative to that of a container freight being pulled as part of a semi tractor-trailer/s load? That would be instructive. To make it a truly comparable any extra handling and miles rail freight accrued relative to that of truck shipped freight would have to be accounted for but that might be just tad hard to work out.

On another subject of interest to us both:
I don't know if you had a chance to check out the 22 page paper, History of sea ice in the Arctic, published in Quaternary Science Reviews 29(2010)1757–1778 phil harris linked down the page. I'm about a quarter of the way through it (in the middle of "Types of paleoclimate archives and proxies for the sea-ice record," a thorough and balanced accounting). It is very much worth the effort.

Maybe, maybe not. There are exceptions, but many of the rails that got converted to trails were old and twisty, difficult or impossible to bring up to modern standards for curves and the like. (And those standards won't go away, because you can never backtrack on bureaucracy no matter how dire the circumstances - better to be "safe", even if it kills you.)

a ton of coal produces about 2.86 tones of CO2 according to this source
So the good news is that if Rutledge is correct, there will be
8 trillion tons of CO2 factored into the IPCC report that will not be generated.

This is about 240 years' worth, at current rates, if I have my math right. Our Choice says we produce 90 million tons per day

I've seen comments similar to yours fairly often throughout OilDrum, and even in this thread. I want to point out that the IPCC report isn't gospel - climate science is evolving, and the IPCC is a large group of diverse viewpoints, and subject to external pressure.

We really don't know what a safe level of atmospheric CO2 is. About a decade ago it was thought to be 450ppm, now James Hansen says its closer to 350ppm, which we have already exceeded. It's possible that there is already enough greenhouse gas in the air, combined with positive feedbacks, to completely melt the icecaps, and raise sea level by roughly 70 meters. We wouldn't know right away, because there is so much thermal mass in the air and ocean that the warming takes decades to centuries to arrive. In fact, the ice core records don't include a CO2 level as high as we have now, which suggests that we are way over the line.

If that is the case, even if future coal production has been vastly overestimated (which I don't have the knowledge to argue either way) we will still see catastrophic climate change. We'll just see it in the dark without any air conditioning.

It's possible that there is already enough greenhouse gas in the air, combined with positive feedbacks, to completely melt the icecaps, and raise sea level by roughly 70 meters.

I really think that this is very likely incorrect. We are likely to be as warm as the Eemian at present, and will almost certainly get warmer, however as Antartic and Greenland ice-cores span the Eemian we can be confident that such warming did not seriously impact the bulk of either ice-sheet. Antarctica is high and enclosed by the polar vortex so it's interior is largely isolated from the surrounding warming ocean. Although the West Antarctic Ice Sheet, being grounded below water, may be at risk; it'll take much more warming to melt the bulk of Antarctica. Greenland is at more risk, but again it's melt will probably take many centuries. That makes resultant sea level rise rather a slow process and hence likely to be manageable.

Regards this study.

What is interesting about this work on coal is that it does seem to me to cast more doubt on the highest IPCC scenarios. Although it should be borne in mind that these scenarios were drawn up from economic considerations, assuming that demand is the key driver. This and the other attempts to estimate resreves can be used to remove scenarios from reasonable consideration.

I still think that Kharecha/Hansen is the most useful paper in respect of fossil fuel depletion, using their coal phase-out scenario, at 330Gt Carbon emissions fro 2007 to 2050. Assuming a conservative 70% carbon content that's ~470Gt coal, well within the 680Gt coal found by Euan Mearns in the lead article. As K/H's scenarios b to e all implicitly assume this conservative emission of coal we can say that it's likely humanity can't push CO2 much above the region of 500ppm.

This back of envelope calculation does not include feedback-emission from the natural sources. However note that most of these sources are likely to be relatively slow (chronic, not catastrophic), excepting Arctic Permafrost emissions: Both changes in ocean CO2 uptake and Arctic CH4 clathrate destabilisation are rate-limited by ocean warming rates, and in the latter case sediment waming rates.

None of this can be used to argue that climate change is not a factor. However it seems to me that the worst case scenarios are looking less likely, which can only be considered good news.

This post and discussion is mainly about coal and how this links to IPCC emissions scenarios. Going off and discussing how these emissions scenarios may impact actual climate is off limits.

Then shouldn't he have not mentioned the IPCC at all?

Exactly. The only reason anyone cares about the IPCC scenarios is because of what they predict for future climate change. Its completely legitimate to discuss the effect of declining coal availability on projected future emission scenarios, but its equally valid to point to evidence that those scenarios may be wildly optimistic in their projected impacts. I posted links to two sources that suggest dangerous warming can occur at the CO2 levels we have in our air today. That post was deleted.

Thought police at work. Come on. Unreal and embarrassing.

If you want to discuss coal, then the article should be prefaced with something like the following:

"The following discussion concerning coal makes no claims about its effect on global warming."

Off limits. Gag. I thought the Oil Drum actually encouraged thinking. Apparently not.

Thanks for the interessting article.

One minor comment on German coal reserves. I've talked to some German coal miners of the Ruhr region recently and they stated that there are definitely large coal seams up to 6m thick in large numbers left and not yet mined because of different reasons (deep >2000m, no mines left in the regions of the seams - e.g. Saar, environmental restrictions, etc.).

So maybe this coal will never be mined, but there are definitly large amounts of coal left with significant positive EROEI, even in mature regions like Germany, but they are not mined because we are not China and do not bring up anything "at any price". The reason the price of the Germany coal is that high is not only geological (of course it is to some degree - 1800m deep mining etc.). But a German miner earns about $5000/month, a Chinese maybe around $500/month if he's lucky, environmental restrictions in a dence populated region like the Ruhr area in Germany are extrem etc.

This profile of Germany suggests that production has declined due to the closure of inefficient mines in the former East Germany; also hard coal is favored for imports of course, Poland being the largest supplier. Factoring in desperation and/or nationalism to these models would be apt, I think - a former industrialized nation suddenly suffering through brownouts will likely drop all these secondary concerns tout suite. Or perhaps react by building out cleaner energies, who knows? But much of these resources remain viable to extract, just not economical, and as long as economics dominates the game they remain in the ground.

Nice to have you around again Dave.

I calculate your Coal ultimate to be something around 480 Gtoe (I work with these units). Jean Laherrère, who also uses data from the BGR, is presently coming to a 700 Gtoe ultimate. The EWG assessed something between 600 and 650 Gtoe. BP reports available reserves of some 700 Gtoe.

The essential question is: what makes you prefer the ultimates provided by curve fitting methods over the reserve estimates?

Hi Luis,

Thanks for your comments. The view I take in the paper is that with respect to estimating long-term production, the curve fits and reserves are complementary. Reserves numbers are available early, and they provide a loose upper bound. Curve fits are unstable in the early years, but they have been more accurate than reserves once they stabilize.


Thanks very much for this Dave. When you first posted this assessment I was somewhat sceptical that such large amounts of coal would be left in the ground.

Since then I've come round to your analysis. the price of coal has increased substantially over the past 2-3 years to the point where now Nuclear Power is unequivocally the cheapest form of electricity production on the East Coast of China. The Chinese have responded and now propose 245 reactors by 2030 (from 11 in 2009). The number keeps going up. So all those deep seams look like being priced out of the market just like British Coal.

What you write is not correct: "However, all the estimates for the long-term production, and the cumulative production plus reserves are completely different from what the IPCC (United Nations Intergovernmental Panel on Climate Change) assumes is available for production in its scenarios."
Not "all":

You have missed for example scenario B1 which has C emissions of about 700 Gt (including coal, oil and gas, so coal is smaller than your estimate).(With that scenario a temperature rise of 2 degrees centigrade is calculated by 2100 compared to 2000, btw.). (See figure 10.26 in IPCC 4th report chapter 10).

Furthermore, keep in mind that the scenarios you criticize were constructed 10 years ago, and are being updated as we speak for the next assessment (see for instance "IPCC Workshop on New Emission Scenario
Laxenburg, Austria, 29 June - 1 July 2005"
The scenarios are NOT predictions, but a purpose for the scenarios are also to be used as sensitivity studies for the models.

The evolution of scenarios is discussed to produce a class of "most probable" scenarios, that better can be used and understood by end-users. But that brings on a range of difficult questions too.

Id suggest you stop bashing on that particular A1 scenario - it is NOT a prediction.

All the IPCC scenarios assume the same large fossil fuel reserves, they just don't use them up. None of the scenarios become supply-side limited. This analysis doesn't bash any particular scenario, but the assumptions the whole SRES (and the new RCP) family sits on.

Well two things:

1) dont you agree it is slightly dishonest to make an analysis (main post) and say: "coal is less than literature, 700 Gt". then Dave compares that with one of the high end scenarios: "look thats ridiculous". If that aint bashing I dont know what. Why dont dave compare it with one of the lower sccenarios "look that scenario is same as my estimate"?

2) the new scenarios might still have too high reserves, but if the reserves are not used up we are getting to reality as TOD thinks it is, thats a fairly correct approach no? furthemore in
there are discussions on "Inclusion of long‐term features not previously included in model comparison exercises, such as peak‐and‐decline behavior"
Note: PEAK and decline. I think it is fair to say that IPCC is working on getting fair scenarios out for the next report.

Hi Segaltamp,

Thank you for your comments.

For 1), I believe that Chris Vernon's response above is appropriate.

For 2), whether one prefers to use reserves or production curve fits to estimate long-term production, at least both the reserves based on seam maps and the production histories do connect to geology. The new IPCC scenarios (representative concentration pathways, or RCP's) are defined in terms of the radiative forcing in 2100 with three mitigation RCPs (2.6,4.5,and 6.0 W/m^2) and a fourth unconstrained scenario (8.5W/m^2). People who are interested in this can start with Jae Edmonds' presentation:

Edmonds states that the RCPs are "designed to yield radiative forcing values in 2100 that would give significantly difference [sic] climate outcomes."

This means that for the mitigation RCPs, the production numbers are effectively backed out from the assumed radiation forcing in 2100. The peak you mention is for the radiation forcing in RCP2.6. However, this peak is arrived at through climate policy rather than exhaustion. This makes the unconstrained RCP8.5 the appropriate one to compare with the results in my paper. RCP8.5 gobbles up a multiple of the reserves, just as the early high-end SRES scenarios do.


I am really interested in understanding what your problem with the RCP8,5 or 2.6 is.
I dont see why you have to point out that an IPCC scenario has a too large reserve. The model runs only care about the concentration of CO2 equivalents (roughly) in the atomsphere.

If there is a scenario 2.6 that corresponds to your production then all is well, no? You could state "that scenario, with this effect, is the one I personally predict is the most probable"? that is what the different scenarios are made for. Everybody should find one to his or her taste! and argue which one is the best path to follow.

The models simply dont care about C (reserves) left in the ground.

Again your alarming that the reserves are too big has little practiacal effect, as long as all scenarios are considered "the same", and there are scenarios with a peak included.

I mean you seem to hang on that IPCC should state "exhaustion" rather than "climate policy". Sure IPCC might say that now that IEA has said that. But it is only wording. The CO2 in the atmosphere is what matters for the model, and the peak scenario is already in there. I dont see the problem.

The IPCC needs to be basing their scenarios on the most accurate production figures available otherwise the scenarios are actually useless to policy makers who may be tempted to make the wrong decisions. If a scenario exists wher peak coal, peak oil and peak gas are all represented as accurately as currently possible, the policy options for dealing with climate change as well as the hard ceiling on energy supplies may well yield a better policy response from what we are getting from governments at the moment.

Any climate change scientist who refuses to even consider new information on possible geological limits to CO2 emissions is being scientifically dishonest. Personally I feel this is an area that the IPCC needs to do much more work on and if necessary, use its position to force open OPECs books and every other country that would conceal its resource and reserve numbers for all hydrocarbons.

And for the record, it is not the concentration of CO2 that matters, it is the radiative forcing and its subsequent effects that policy makers need to manage.

There exists exactly scenarios that peak coal peak oil and peak gas are represented. "as accurately" is the hard part - you realize that too right?

Are you not overstating the power of the 15 person office of IPCC slightly "to force open OPECs books" - that is outside the realms of 10 researchers daily work, no? You know, IPCC has a defined mandate from UN: to collect climate relevant peer reviewed articles and analyze these... thats their job, nothing else.

Ofcourse it is the radiative forcing that matters (from CO2 and greenhouse gases and feedbacks (albedo aerosol and H20)). Excuse me for slightly simplifying for readability in my answer above. But surely you understood that too, right?

We agree about several things, thats the good part. I just would like you to quantify and source your statements above ("accurately" - how, by whom; "better policy response"; "refuses to even consider" - who do you mean and where have you read that; "needs to do much more work" - where have you read what they do currently and HOW do you want that to change - please detail otherwise pointless).

Segeltamp, your logic is correct. Reserves in the ground are not relevant to climate, only that produced and burned/not sequestered is. While the assumptions of the IPCC were based in reserves estimates and production estimates, theirs is not a document about economics. What ultimately matters to climate is only what is produced and burned.

What should concern Rutledge is that we are matching the highest estimates thus far and that the scenario you mention that matches his estimates is already far behind reality.

Euan has put this off-topic, tho, so final word, I expect.

The message from this post is that the global coal reserves, at the current economic price, are a lot lower than is widely expected.

The implications for this need to be considered in the context of the global primary energy supply. Coal, oil and NG between them are about 80% of that energy at present.

We all know about peak oil. Natural gas has not peaked, but an increasing part of the remaining reserves are either in locations remote from their markets, requiring expensive LNG transportation, or are shale gas which is more expensive to extract.

The combined effect is that the global energy supply is getting more expensive. That means in practice the ERoEI is declining. More and more resources need to be invested to sustain or increase the total energy supply. The energy production part of the economy is increasing at the expense of the rest of the economy. Sooner or later the increasde expense of extracting fossil energy cuts into and decreases the rest of the global economy, and so cuts energy demand (at that price). The world will have hit peak net energy. We may already be at that point.

Soon after that, we will hit global peak energy. Total global GDP will decline.

Of course, we should be investing in non-finite energy sources as fast as possible, because these tend to have large, up front capital costs, but see the recent post by Nate Hagens to understand why we are not doing this as fast as we should.

Nuclear power is a more complicated case. The current technology is based on a finite fuel supply. It has huge upfront capital costs and unquantifiable decommissioning costs. It is a high technology energy source which will be hard to sustain in a globally declining energy environment. There are huge logistic bottlenecks to its rapid expansion. It has contested environmental impacts and is a political impossibility in many countries.

At this moment, the general consensus is that we must No go about amession of 1000 GT of CO2 to avoid à 2C of temperature increase.

You coal reserve estimate are way above this limit. Also, this does not take account of oil and gaz, especially non convetional. Also, it does not matter much how fast these reserve are consummed. This will only delay to moment when the equilibrium temperature is reached by a few decades.

I don't think it's accurate to speak about economically recoverable reserves in vacuum. Yes, as the price of coal increases with demand, it becomes more economically feasible to extract a greater percentage of the world's known reserves.

On the other hand, what is that price point and what will such a price for coal do to the economic viability of other sources of energy? At some point, it becomes cheaper to use other fuels, such as natural gas, nuclear, or renewables, than it does to mine coal, drive up demand, and commit to a long-term higher price of energy.

All the arguments in favor of coal use and expanding coal use are economic in nature: this stuff is cheap. But to keep it cheap, we have to abandon hope of recovering much of the world's vast coal resources because recovery of those resources is more expensive. At those kinds of prices, coal starts to become much less attractive: it's bothersome to transport, difficult to extract, of inconsistent quality, and difficult to burn efficiently and cleanly. It's really a sub-optimal fuel.

High liquid fuel costs, high natural gas demand, and some economically viable coal-to-liquids process projects may change the calculus, particularly if some of the prototype technologies for in-situ coal gasification take off, but consider what other hydrocarbon projects are in the (pardon the pun) pipeline:

-Japan has recently undertake serious research into methane gas hydrate extraction. This may seem a long-shot technology, but that's what people said to Sony about digital imaging in the late '80s and what American engineers said to Toyota about hybrid drive technology in the 90s. The Japanese business sector has a history of sticking with these long-term R&D projects, so I wouldn't be surprised if we saw the first commercial gas hydrate extraction facility open up in the next 10 or 20 years. This would dramatically expand global gas reserves.

-Shale gas goes ever on. There are concerns about it's production ability and impacts, but I suspect these will prove to be more technological issues than geological and it certainly doesn't seem to affect the futures trade.

-Oil sand developments continue, with the total cost lowered by currently cheap natural gas. This may change in the future, but any attempts at CTL technologies would require even more massive thermal inputs.

-Coal is falling out of favor as the electrical generating fuel of choice in the US and an expansion of nuclear power, renewables, and a deployment of more efficient coal burning designs in the developing world has hedged future growth projections. This is as much an infrastructural issue as anything else: in the States, we're tearing down old coal boilers, with more to follow in the next decade or so, so our actual ability to utilize this fuel source in the future is diminished. Furthermore, it's just as likely that high electricity demand and high fuel prices will make other sources of generating electricity just as economically and politically attractive as coal.

-And what about oil shales? Sure, they're expensive to use, but we're talking about a future where energy is expensive enough to make reserves of coal which are currently totally uneconomical profitable. It takes just as much effort to strip mine shales as it does coal and the industry expects profitability at $95/bbl (higher with higher natural gas prices). This cost comes down as economies of scale are deployed. Either way, any future renewed interest in coal to liquids technology, as I believe would be the saving grace of the coal industry, would have to compete with unconventional petroleum production from tar sands and oil shales.

So there's a lot of economic considerations, infrastructural considerations, and we have to think about what future technologies currently under development may yield. In short, the point at which these currently unfeasible coal reserves are extractable may also be the point at which other technologies and sources may come online and how that would influence deployment of coal consuming technologies in the future.

Since coal is relatively expensive to ship overland, the rate at which mid-continetal reserves are consumed would seem to be related to the demand for electricity within a couple thousand kilometers of the reserves. This would be the case for Montana, Western China, Siberia, etc. Where large amounts of gas and oil are also available in the same vicinity, such as Siberia, it is likely that the reserves stay in the ground longer and are used less widely.

On the other hand, countries which have available coal reserves but limited other supplies of fossil fuel are likely to exploit them beyond the point that would be consistent with a "global" model of reserves and economic value through a variety of subsidies.

Lastly, if Peak Oil seriously jeopardizes the welfare of the economically well off, the think tanks will be funded to reevaluate their conclusions, public opinion will be reconditioned, and environmental concerns will go out the window.

Nations that have access to coal will use it, while others will depend on imports of gas or nuclear fuel.

How did you treat Utah coal reserves?

On the basis of a preliminary report recently released by the U.S. Geological Survey (USGS), there are 62.3 billion tons of in-place coal resource in Kaiparowits Plateau coal field. Of this resource USGS indicates that there are 30 billion tons of minable coal in various beds. According to the USGS report "These beds of coal are in areas where overburden is less than 3,000 feet thick and strata dip less than 12 . The coal tonnage is estimated for all beds of coal that are more than 3.5 feet thick, and coal tonnages in beds that are thicker than 14 feet thick are calculated as if they are only 14 feet thick." They also estimate that the total tonnage in beds of 3.5 feet to 7.4 feet is 15 billion tons. Using Utah Geological Survey figures, we estimate that 7.25 billion tons of coal are in seams of 3.5 feet to 6.0 feet which are considered uneconomical to mine in Utah. Removing this thin coal from the 30 billion tons estimated leaves 22.75 billion tons of minable coal. Applying a 50 percent recovery factor means the Kaiparowits Plateau contains an estimated 11.375 billion tons of recoverable coal.

The economics of mining Utah's coal depends partially on the size of each deposit and its proximity to a rail line. If the coal bed has 10 million tons, but is 100 miles from a rail line, the added cost ship by truck is $5 to $10 per ton, counting infrastructure cost of highways. So, is this coal competitive with other coal close to rail lines? Probably not.

My prediction is that a lot of the coal that is not near a currently operating rail line may never be mined as the cost of diesel fuel heads higher and likewise the infrastructure cost to build upgrade highways or build new rail lines heads higher too. As FF prices escalate so does the cost for steel, concrete, and equipment operations to build infrastructure. Law of receding horizons will make some coal uneconomical forever.

Hi Merrill,

Utah's production shows a two-cycle pattern like most of the western states, and it is included in the Western US region in the analysis.

The Kaiparowits Plateau is part of the Grand Staircase-Escalante National Monument, created by President Clinton, and that coal cannot be legally mined. I believe that it should not be included in the EI reserves for Utah, which are currently 2.7Gt.


It will not be mined while we have money to import oil and until natural gas supplies are depleted, but it will be mined before people will freeze in the dark. Same thing with Alaskan coal.

sad but very likely true, but if we ever start really going after those huge northern coal deposits (that have only been mapped in the most cursory manner to date) the freezing part may not be relevant on much of the planet's surface. Most of the scenarios that put peak coal in the near term assume some other energy sources stepping up cheaply as oil prices and electrical demand skyrocket in tandem--lets hope those are the correct assumptions.

Of course the peak coal predictions based on just not enough capital left in the demolished world economy to develop those northern coal resources assume the opposite, that nothing cheap comes on line and the modern world as we know it comes to a crashing halt.

One thing looks certain shipping lanes to the much less frozen north are going to be a lot larger and open a lot more of the year. Four of the last four years have had the lowest minimum ice extant on satellite record, 2007 having the least ice followed by, 2008, 2010, 2009--I know that modern satellite only goes back to 1979, but as the ice recedes some significant sediment core surveys should give us far better insight into the last million years or so of the arctic ice cycle.


I just wanted to congratulate you on providing the Excel spreadsheet along with your results. I expect a large amount of effort went into compiling the historical numbers and making them freely available is a huge stride toward a more 'Open Source Science'.

If scientific results are supposed to be reproducible, scientific papers should always be accompanied by the data and software from which the results are generated. David's inclusion of an Excel spreadsheet is so remarkable because it so rarely occurs.

Thanks for setting a good example,


add my thanks for your comment.
(proprietary science is a contradiction in terms, IMHO)


The problem that I have with this analysis is to do with the distinction between known resources and reserves. We are in (or rapidly coming to, depending on who you believe credible) a period where crude oil is going to be perpetually over $100 a barrel, because of the costs for production at the margin needed to meet global demand. The demand for domestically based alternate fuels will thus rise.

At present coal is still one of those products (Germany being an exception to the almost global rule) that it is the cheapest producer that gains the market, and that there are still many deposits where all you need do is scrape the dirt from the top and buy a bigger shovel and then, provided you can provide transport the coal, it costs very little (about $10 a ton) to produce. Even within those constraints we have the example of Botswana who, until recently had 1 power station, 1 mine, and 1 mining machine - all that was needed in a country that bought most of its electricity from South Africa. The reserves of the country were therefore considered to be very small. Then South Africa decided it needed its power for itself, and the feed to Botswana is being cut off. Suddenly there are coal mines being developed and reserve estimates continue to climb. And the Chinese are helping, since this could be another source for future supplies and so the reserve base is climbing (up to 200 billion tonnes ).

Even in the UK the need to meet future energy needs (as opposed to goals) are causing the government to have a bit of a rethink on their coal-fired power plans.

Coal's biggest competitor at the moment is natural gas, and the plentiful cheap supply of this to power plants is restricting and confining the coal market. However there is a production cost and ability to gas from shale, that Art Berman has written about, that will, over time likely reduce the volumes that are available at a competitive price, relative to the price and availability of coal for power stations. At which time coal supply will require the conversion of more of what is now only a resource, back into a reserve.

Hi HO,

Thank you for your comment. The current range for the historical fits since 1995 is 653-749Gt (14%). We can accommodate Botswana.


Well yes but there is a whole lot of Africa that might be in the same boat as Botswana.

It is interesting that the EIA, writing in this week's TWIP, has shown that the crude reserves in the US increased by 9%, and natural gas by 11%, primarily as a result of the increase in price. The world is already learning that governments can't legislate technology (vide cellulosic ethanol), although it might take a long while for some governments to learn that lesson.

In the meanwhile, with your indulgence, I have posted a somewhat longer reply on Bit Tooth.

Hi Dave,

Thank you for the link.


Here are some of my thoughts:

First, why ask how much coal we have? Don't we want to reduce or eliminate coal because of climate change?

Yes, we do. For better or worse, however, it's important to be realistic about the availability of coal. If we're not running out of it, we have to make a conscious decision to eliminate it, not rely on geological limits. Also, it's good to know whether or not we'll face energy shortages due to coal scarcity. If not, we have more options - if we face an emergency, we will have the option of using coal. Of course, that may be expensive and difficult to do without excessive CO2, but options are usually good to have. In that vein, we should note that if we have coal to spare it's actually easier to sequester CO2 - sequestration consumes a fair amount of energy, and if things are tight it will be much harder to pay for something whose necessity isn't obvious to all .

So, do we face limits on our coal production, as a practical matter?

No. Coal is unlike oil - we have enormous reserves, we know where they are, and in many cases there is no significant increasing marginal cost to their extraction, except for temporary costs of expansion.

Do higher energy prices raise the costs of extracting fossil fuels?

It depends on the individual case. Coal has a high E-ROI. For instance from a recent survey by Heinberg ( from ): "Consider the case of Massey Energy Company, the nation’s fourth-largest coal company, which annually produces 40 million tons of coal using about 40 million gallons of diesel fuel—about a gallon per ton" .

That's a very high E-ROI: a gallon of diesel is about 140K BTU's, and a ton of coal is very roughly 20M (see ), so that's an E-ROI about 140:1! Now, diesel costs very roughly 10x as much per BTU (reflecting it's scarcity premium), so the cost ratio isn't quite as favorable, but it's still well above 10:1. So, the price of diesel rises by $1 (roughly 25%), and the cost of coal rises by $1, or very, very roughly 2% - not a big deal. Also, we should note that coal mining (and transportation) is often electric even now (especially underground), and that it's pretty amenable to further electrification - in other words, coal mining can power itself using a small fraction of it's production.

Will higher coal prices make a substantially larger fraction of the coal available for extraction?

Yes, but only slightly higher prices are needed. Here's what Heinberg has to say: "if Montana and Illinois can resolve their production blockages, or the nation becomes so desperate for energy supplies that environmental concerns are simply swept away, then the peak will come somewhat later, while the decline will be longer, slower, and probably far dirtier.". The Montana "production blockages" he talks about are relatively trivial, and Illinois doesn't really have them. The pollution he refers to is CO2 and sulfur - the sulfur costs about 2 cents/KWH to scrub, and the CO2 might cost out at $80/ton of CO2, which IIRC would add about $30/ton of coal, should we choose to internalize this cost.

Illinois coal simply couldn't compete with Powder River coal with a 2 cent premium for sulfur scrubbing - it's as simple as that. UK and German coal became a bit more expensive, and they couldn't compete with cheap oil.

The same general rule applies to US, UK and European coal: only under Business As Usual is coal declining. I discussed this at length with David, and I thought we came reasonably close to some kind of agreement on this. If there are serious energy shortages, the old reserve numbers will apply, for better or worse.

So, would a doubling in coal prices substantially increase recoverable coal reserves?

Yes. Now, "recoverable" is tricky: the normal distinction used by the USGS is "economically recoverable" - that includes economic assumptions, and Illinois coal (and much other coal in the world), at a slightly higher cost as discussed above, is currently uneconomic. But, that's under Business As Usual - if we have a true energy scarcity, Illinois coal will very, very quickly become economic.

What about the "Law of Receding Horizons"?

That applies only to low E-ROI sources of energy. Coal is high E-ROI, unlike Canadian bitumen (tar sands) or Colorado kerogen (oil shale). I would note that the importance of this "law" has been enormously exaggerated, as it's confused with temporary capex issues and scarcity premia, which are allocating temporarily scarce capital resources.

More coal gets extracted from the ground each year as measured in tons, but hasn't the quality declined so much that net energy content is lower now than 10 years ago?

Powder River coal is lower energy density (sub-bituminous), but it's sufficiently cheaper to mine that the difference doesn't matter. Again, this is a purely economic shift from Illinois coal, which is higher energy density (bituminous). This shift has caused endless confusion to analysts unfamiliar with the coal industry (OTOH, people inside the industry understand this).

Aren't coal prices rising?

In many cases, this is due to the temporary costs of expansion. Oil & gas are much more expensive per BTU due to a scarcity premium, and so demand has increased for coal. Most coal is on long-term contract, not on the higher spot market (unlike oil). But it's important to be clear that in many places, like the US, the long-term marginal cost of extraction isn't really increasing, as it is for oil.

Is Coal-to-Liquids (CTL) feasible?

Yes, but projects tend to be large and expensive, and would be CO2 intensive. That means that investors would like federal loan guarantees, but that such guarantees are unlikely. Nevertheless, CTL is cost-effective even with fairly high carbon taxes, with oil prices at anything like the current level , and projects are slowly moving ahead . The best path would be CTL with CO2 sequestration - this would deserve guarantees.

Is oil-shale feasible?

With oil over $100/barrel, the answer is almost certainly yes. There's something like a $50T incentive there for exploitation, and somebody is going to make something work. In that way its similar to the Bakken basin, which may have 400B barrels of true oil, though only 4B is economically recoverable right now.

Kerogen has the advantage of not needing hydrogenation (which is needed for both tar-sands and CTL), which requires expensive natural gas or a combination of added energy and water (also a significant cost).

On the other hand Green River kerogen (mis-named oil shale) is low density, and a pain to dispose of after burning (it expands). That's why even low-value coal is more attractive for burning (which is what the Estonians do with it). That's also why retort conversion to oil (the conventional method) is unattractive, and why Shell is considering in-situ conversion instead.

Further, kerogen requires a lot of energy to upgrade - the Shell process looks very much like a very slow, inconvenient method of converting electricity to oil (kind've like ethanol, except ethanol mostly uses natural gas). All in all, it seems inevitable to me, but not cheaply or at large volumes any time soon.

I wouldn't reject it, as it is extremely valuable to have diversity in energy supply, but it would be much better to concentrate on electrifying our vehicles ASAP. In other words, we can't let it distract us from the main and best solutions available to us, which are, unfortunately, inconvenient for oil & gas and car companies.

Perhaps most importantly, kerogen burns quite nicely. If we were to run out of coal, we could certainly burn kerogen, and we certainly would before we let the lights go out.

Your entire post leaves out the transport cost for coal and therefore diminishes most of your arguement about coal costs.

Did you know that between 50 to 60% of the cost of western coal (PRB) used by eastern utilities to meet emission requirements is for transport by rail or truck/rail combination? And as fossil fuel cost rise, so will the cost of this transport, making coal even higher priced.

The railroad, which transport about 90% of the western mined coal, have tremendous power to increase prices for their services and I don't see this portion of delivered cost for coal going down relative to the mine3d price.
Outside of building mine mouth power plants and new HV transmission lines for trillions of dollars, I don't see the high railroad cost aspect being avoided.

You're right, I didn't address this question directly (for a discussion of oil inputs for coal mining, see the section titled "Do higher energy prices raise the costs of extracting fossil fuels?").

A $100/bbl increase in the cost of oil would increase the cost of transporting a ton of coal by $100/bbl x 1bbl/42 gal x 2 gal/ton* = $4.8/ton. That's a 2.5% increase in the cost of electricity, which means that railroads will be easily be able to out-bid other potential users, like trucks.

Coal transportation by rail can also be converted in a relatively straightforward manner to use electricity instead of diesel, meaning that reduced oil supplies are highly unlikely to have a significant direct impact on the ability of the US to transport coal.

We're going to have to make a conscious decision to eliminate coal - it's not going to run out, and make the decision for us.

*Rail transportation is about 440 ton-miles/gallon on average, and coal is at minimum 500 tm/gallon. Coal trains are probably even more fuel efficient, because the ratio of load to tare weight is greater than most other rail freight (particularly intermodal). 600 tm/g might be a good estimate. Low-sulfur coal in the US travels roughly 1,000 miles before being used (high sulfur coal travels much less). Dividing these tells us that transporting US coal requires roughly 2 gal/ton.

Did you know that between 50 to 60% of the cost of western coal (PRB) used by eastern utilities to meet emission requirements is for transport by rail or truck/rail combination? And as fossil fuel cost rise, so will the cost of this transport, making coal even higher priced.

That's because the cost of western coal (PRB) at the minemouth is incredibly low, less than $20 per ton.

Electricity in the US is about $0.10/kWh, and US coal generates about 2,000kWh/ton. That gives a retail price of electricity of $200 per ton of coal used, so a cost of $10/ton for coal represents only 5% of the overall retail price.

".... Low-sulfur coal in the US travels roughly 1,000 miles before being used (high sulfur coal travels much less). Dividing these tells us that transporting US coal requires roughly 2 gal/ton. "

Nick, your calculation is off by a factor of at least 2. The coal train may run 1000 miles to the power plant, but then returns empty, so the train makes a 2000 mile round trip for each load. That fuel use would be more like 4 gallons per ton.

Because coal trains wear out the track structure much faster than passenger trains and intermodal (container) trains, the cost per mile to operate such is the highest of any type of train. As railroad maintenance and operating cost increase, coal traffic will get a larger share of these costs. I know what rail industry cost drivers are as I worked for Burlington Northern and Santa Fe railways in the years prior to their merger. The successor company, BNSF Railroad, is the largest coal hauling RR in the western hemisphere.

We might need more data.

We don't have coal-specific fuel consumption data; we don't know what % of coal trains must return empty ("dead-head"); we don't know exactly how much consumption declines when a train is empty.

Fuel consumption is driven by 1) acceleration and climbing; 2) drive-train friction; 3) wheel friction; 4) wind friction. 1 and 3 will rise (and fall) with weight, but not the others. If coal trains wear out the track structure much faster than intermodal (container) trains, then they must weigh much more, and be substantially more efficient on average. Conversely, dead-head trains would consume less fuel, but the decline won't be 100%.

If the industry stat is 440m/g, we can assume that coal gets at least 600 miles/gallon one way (1.52 gallons per 1k miles). The empty train might use 50% as much the industry average for fuel on the dead-head leg (or, in effect, 880m/g, or 1.14 g/kmile). 1.52 + 1.14 = 2.65 gallons for the 2,000 mile roundtrip.

The 440m/g industry stat must include dead-heading: IIRC coal is roughly 1/3 all US train traffic, and it's not the only freight with this problem, so the above calc (which allocates this overhead cost only to coal) is conservative.

Because coal trains wear out the track structure much faster than passenger trains and intermodal (container) trains, the cost per mile to operate such is the highest of any type of train.

That makes sense. OTOH, that means that cost per ton of freight will be much lower than average.


So, do you happen to have better data for these calculations from your railway days?

Railroads can be nationalized, or regulated to such an extent that they might as well be nationalized.

I don't expect to see this happening within the near "near term" but I wouldn't be suprised if rail nationalization or something effectively equivalent were to be part or a major political party's platform by twenty twenty.

Yair...on the other hand our government has just sold off the largest narrow gauge coal hauling operation in world.

When Dave first posted here 3 years ago I was very much on the side of Heading Out, believing that the death of the UK coal industry was down to Thatcher, politics, economics and Norwegian trout that reportedly did not like the acid from our S rich coal. But I see things rather differently now, in no small measure to Dave's work.

First part of learning curve is to see where Thatcher and the miner's strike (1984 - 85) fits into the long-term decline of UK coal, that began sometime around the decision made by Churchill (then first lord of the admiralty) to convert the Royal Navy from coal to oil - the rest is history.

The rest of the debate is rather more complex. 19th and 20th Century infrastructure - cities, railways, docks, power stations etc. got built close to the most easy to access supplies of energy. Now infrastructure is in the wrong place for what remains.


Have you seen any price history for coal, before WWII and in the UK? I've looked, and I can't find it. Surely a price history would be an essential part of a "peak" analysis?

So the correct causal relationship is that North Sea oil provided the basis for a new economic prosperity, enabled the government to take on the coal miners and other unions, and made Maggie Thatcher and her policies possible -- rather than the other way around?

Exactly. EJ = E£.

Its a broadly held view that NSO revenue allowed Thatcher to stick everyone on the dole and discipline wages/smash the unions. The irony being that NSO was a stop gap during the Iran Iraq war and was sold off on global markets at a depressed price during a global recession.

substantial amounts of the dole(welfare)money was spent buying drugs which in turn funded the war in Lebanon

not sure where the money is coming from this time round

so its time to dig up the coal is it?

the long-term decline of UK coal, that began sometime around the decision made by Churchill (then first lord of the admiralty) to convert the Royal Navy from coal to oil

The Navy's conversion affected consumption, not production. I was interested to find out recently that UK consumption didn't start declining until much later. Instead, declining production was reflected in declining exports.

It would be interesting to extend the consumption curve in your chart back to, say, 1900.

Consumption: - Yes. I've been meaning to write to DECC to see if such data exists for ages. Will do tomorrow.

I'm sure long term coal price data exists, maybe even on my hard drive, but no means of accessing it right now.

Thanks for your chart.
I recently found this, which is where I got my figure (my comment higher thread) that nearly 90% of UK primary energy consumption was still supplied by coal in 1950.
(Was touch and go for Thatcher in 1980s - early severe recession - UK couldn't hack it on coal after oil shocks? - then lucky Falklands. Most gas came ashore after she was gone IIRC?)

From Pearson 1998 The Energy Journal
Accessed online October 22, 2010

An amazing paper - maybe make some charts from that data - pity they use tons coal equivalent, some conversions required.

Glad it might be of use.
Sorry I did not check the link myself this morning and say that the immediately relevant table was page 33 of the format I was looking at - saves time for busy people, but I too thought the preceding text has a lot of value.
Yes, pity about the conversions from coal equivalent - I am helluva slow at that kind of thing!

For another interesting article see:
Seven Centuries of Energy Services: The Price and
Use of Light in the United Kingdom (1300-2000)

Roger Fouquet who worked seven centuries of light paper above has expanded this into a book 'Heat, Power and Light'see

This discusses a whole range of energy services. In the back are a set of tables which include real costs £(2000)per toe for different energy sources from 1300 to 2000. The book has made it to paperback and is a good read for data nerds (I've had my £24 worth).

The time series for 'heating fuel' I would presume means 'coal' from about 1870 to 1950.

Here's some sample figures for domestic heating fuel £(2000) per toe:
1870 113
1880 112
1890 141
1900 167
1910 242
1920 161
1930 269
1940 286
1950 279

If anything I wish that the book was longer and explained a bit more carefully about how all the figures in it were calculated.

I suspect that part of the rise in real costs between 1870 and 1950 is due to the fact that coal mining is labour intensive and as 'real' wages (relative to food) increase, so the cost of coal goes up.


So production peaked around 1915, but prices fell from 1910 to 1920?

Those figures aren't adjusted for inflation, right?

UK coal production peaked around 1913 but by the end of the First World War other countries had taken much of the UK's coal export market. 1920 seems to be a low point in Fouquet's price time series (which is inflation adjusted).
In the following year 1921 there seems to have been a big coal strike with UK production well down and then in 1926 there was the General Strike when some miners stayed out for 6 months,

Not a happy time.

Roger Fouquet has written a number of articles which look interesting, unfortunately there are mostly behind paywalls.

For example this looks like the type of article many of us would be interested in as a TOD post:

The slow search for solutions: Lessons from historical energy transitions by sector and service

Roger Fouquet,
a Basque Centre for Climate Change (BC3), Gran Via 35-2, 48009 Bilbao, Spain

Available online 6 July 2010.


This paper reviews past energy transitions by sector and service to identify features that may be useful for future transitions. Although often considered a single event, the transition from traditional energy sources to fossil fuels involved numerous services and sectors at different times between 1500 and 1920. The main economic drivers identified for energy transitions were the opportunities to produce cheaper or better energy services. The existence of a niche market willing to pay more for these characteristics enabled new energy sources and technologies to be refined gradually until they could compete with the incumbent energy source. Nevertheless, this implied that, on average, the whole innovation chain took more than 100 years and the diffusion phase nearly 50 years. In the same way, low-carbon energy sources and technologies offer an additional characteristic (i.e. low carbon impact), which might be able to develop gradually in a niche market until they can compete with fossil fuels. However, because of consumers’ tendency to free-ride, a successful transition will need governments to provide protection of this niche market—possibly for decades. Based on past experiences, a complete transition to a low carbon economy is likely to be very slow.

Thanks for the links.
This paper:

has lots of nice diagrams of the transition from one fuel to another for different purposes over time.

It's the kind of thing that might make a good TOD guest post.

Definitely interested in guest post on this - who do you suggest writes it?

Heading Out's point about Botswana is a good one. In Africa at least, the coal isn't there because it hasn't been looked for. Or, someone knows where it is, but circumstances haven't been right to make it economic. As Africa urbanises and develops over the coming century, I guess that its reserves will increase greatly, at least for a few decades.

This is by way of introduction to a larger point. Statistical regularities are where science begins, not where it ends.

Dave's statements that he became dissatisfied with Hubbert linearization because of fluctuations and that "Hubbert linearization is based on the logistic function, and a cumulative normal is a better fit for some regions" set off a warning bell in my head.

The first rule of applied statistics is, don't change your model just to get a better fit. There has to be an underlying reason to do so. What physical and social processes are going on, that mean that a cumulative normal is a better model than the logistic?

I fail to see how any prediction can be made with confidence, without being reasonably sure about the underlying physical and/or social mechanisms. Simple extrapolation of an observed but not explained regularity is the way to go badly wrong. Changing your model "to get a better fit" is a way to go worse wrong.

TOD would gain by having more exposition, and more careful discussion, of these underlying mechanisms and their interaction -- or what we believe them to be. Without a plausible underlying model, statistical extrapolations are, and should be, easily dismissed. The model must be made more explicit.

Interestingly the statistician here, WebHubbleTelescope, has a model - the dispersive discovery model. It seems to me to have great power even though it is very abstract. The question is, can others do better with more detailed, less abstract abstractions?

Large coal deposits discovered in north-western Mozambique

APA-Maputo : (Mozambique) Australian Riversdale mining firm has discovered four billion tonnes of coal deposits at the site of the Mozambique’s domestic Chingodzi airport in north western Tete province, state-run Noticias newspaper reports here on Friday, quoting company officials.

One of the reasons that South African deposits were explored and developed was that the fairly short steaming range of British dreadnoughts required a fairly dense network of strategically located coaling stations.

These guys didn't have to explore very hard, did they?

I mean, the discovery was at the airport.

How much more are they going to find when they check in at their hotel??

Hi Gregvp,

Thank you for your comment. That horse is out of the barn when any parameter that is not derived from first principles is introduced into a model. From this perspective, every possible choice of long-term production represents a different model, and we are simply choosing the one that gives the best r^2. Similarly, the choice between logistic and cumulative normal is not determined by first principles; they are just two different s-curves. The difference between the two for estimating coal production is that the underlying distribution for the logistic has a higher kurtosis (peakedness) than the the normal. We do not have a reason ahead of time to prefer one to the other, so we simply choose the one that gives the best r^2. In principle, we could have a family of models with a continuous range of kurtosis and make an explicit fit for the kurtosis, but this is simple, and life is short.


I was wondering about this as well.

The Lotka-Volterra equations, predator-prey relationship, is based on the logistic function and can be used to model the economy preying on resources, as Ugo Bardi and Alessandro Lavacchi have shown in
A simple interpretation of Hubbert's model of resource exploitation
. So the good fit to the logit transform makes sense. But I don't know what drives the probit fit. Clearly it fits well so you must be onto something. Any ideas on what that something is?

Also, the change in cumulative production fits for South African coal, Western US coal, Chinese coal, and world oil due to the Apartheid embargo, Clean Air Act, Civil War, and OPEC make one wonder what will happen to coal production when oil peaks? Do you expect an increase in coal production rates to offset oil declines?

I read your paper and the one by Patzek and Croft prior to this post in an attempt to model how the economy discovers, produces, and consumes energy. The end goal is to model the renewable and nonrenewable energy sector inputs to the economy then fit the model to get a rough idea of what the consequences of fossil fuel depletion are going to look like.


Lotka-Volterra only works on entities that obey a carrying capacity law. When you solve these equations and you reach some asymptotic steady-state, it means that the population has stabilized to the carrying capacity.

Non-renewable resources have no sense of a carrying capacity and so the equations can't work. They deplete to zero, not some steady state population level.

It only looks like it works because you get an S-curve.

Since Prof. Rutledge comes from the world of physics, he will be able to appreciate that the Fermi-Dirac distribution is also a "Logistic" function in form, yet no one would dare try to derive it using the Lotka-Volterra equations. You would get laughed out of academia if you dared go that route.

It doesn't mean that some other routine statistical approaches can't produce profiles have a Logistic shape. The analysis known as Dispersive Discovery can easily generate a family of distributions that includes a Logistic as a special case.

Thanks for the response, Dave.

Gergyl's comment below mine expands on the issues. The logistic models an underlying physical process, the preconditions for which seem to be satisfied for oil; he says probably not (yet) for coal. The Gaussian is the central limit theorem in action, and needs several independent variables, more where some of the variables are not distributed in a Gaussian themselves. How independent are the parameters for coal?

What I was saying, in essence, is that I would like to see a physical interpretation of the posited exhaustion function. The statistical fit, whatever its r-squared, is just a temporary coincidence without an underlying physical model.

As Euan said in his post "The Chinese Coal Monster - running out of puff":

Figure 6 A Chinese coal production scenario produced by The Energy watch Group in 2006 (page 28 of report linked to above) illustrating how difficult it is to forecast production scenarios, especially pre-peak.

The Energy Watch Group was using a curve fit without any underlying model of what's going on. I'm concerned that you appear to be doing the same, although with better data and better judgement.

WebHubbleTelescope's oil analysis is based on the physical idea of successively more intense search sweeps through a space containing a random distribution of deposits. Other have made less formal presentations saying that energy return on investment drives the decisions and thus the behaviour that we see. What's the real-world basis of the exhaustion function? That's what I'd like to see here on TOD.

Hi grefgvp,

The Energy Watch Group was the first to recognize that the current world coal reserves are likely to be an over-estimate of future production, and they deserve great credit for this. However, they did something completely different from my paper. They were making projections for annual production. I have not done that, because the annual production variation in the four mature regions (UK, France and Belgium, PA anthracite, and Japan and South Korea) was too large. They were using reserves to estimate total future production. I do not do this unless my curve fits fail, because the reserves for the four mature regions have been large over-estimates of future production.

What I have done is to estimate long-term production (total production, past and future). The real-world basis is that the curve fits provided appropriate estimates for the four mature regions, better than ones based on reserves.

I would be cautious about a discovery model for coal. Coal is a rock, and many of the major coal fields can be identified from outcrops. A map of US coal fields made 100 years ago looks similar to one made today. Often the follow-up detailed surveys have had the effect of reducing reserves because it is found that seams have eroded away or have gone too deep to mine. This is one reason that US reserves have trended down over the last one hundred years.


Dave (or anyone),

I had a quick look at your excellent paper and saw that you don't give estimates of Peak Coal (t50's) presumably because of uncertainties and irregular production curves.

Yet many of us are used to thinking that peak dates are relatively important as they indicate a rise in prices (and economic effects) as demand starts to exceed supply. Are you at all able to tell from your analysis (by making a cumulative plot of all the regions, for instance) when world demand starts to exceed supply? Or do you just reckon we'll, more or less, just see a monotonically increasing price over time?

Hi Colin,

Thanks for your comments. For the mature regions, the peaks have come at different parts of the production cycle, 41% exhaustion for the UK and 73% exhaustion for France. This has made me reluctant to predict peak years. On the other hand, the 90% exhaustion year seems to be well behaved for these regions, so I quote that. Part of the reason for this is likely that 90% exhaustion is an integrated quantity. The year of 90% exhaustion might also represent the time of maximum stress, because of rapidly falling production. This was when the confrontation between Margaret Thatcher and the United Mineworkers took place in the UK.


On a minor point that doesn't effect your main point; it was Thatcher v the NUM or National Union of Mineworkers. There was a breakaway union largely based on Nottinghamshire collieries called the UDM or Union of Democratic Mineworkers that was formed and which kept on producing coal while the NUM dominated collieries stayed out on strike for almost a year.

Hi Newbonic,

Thank you for calling attention to the slip. United Mine Workers is the name of the largest American miners' union.


Are you at all able to tell from your analysis....... when world demand starts to exceed supply?

My understanding is that supply and demand are kept in check by price, hence upwards pressure on price last decade suggests demand running ahead of production. I used to think we would see price rising exponentially with falling production as a sure fire sign of passing peak production, but now realise that high price kills demand. There is a very complex set of socio-economic factors linked to configuration of economy, politics, infrastructure, , demographics, geology and technology that determines Man's ability to increase production of any of these resources year on year. Building a bottom up model for the world is a formidable task. Hence the need to fall back on curve fitting techniques such as Dave's. But it is absolutely right that we continue to question and examine the validity and reliability of these models and to never accept them as 'truth'.

upwards pressure on price last decade suggests demand running ahead of production.

I don't have the sense that there is a generally accepted benchmark for world coal prices, like WTI. What do you rely on?

You can look at coal prices in the BP stat review that publish data for Europe, N America and Japan - all are on rising trend last decade.

The magnitude and causes of rising coal prices would be worth some serious analysis. That's the key 2nd element to any peak analysis.

NYMEX Central Appalachian Coal Futures history
NYMEX Coal Futures Near-Month Contract Final Settlement Price 2010
The New York Mercantile Exchange (NYMEX) Report provides settlement price data for Central Appalachian (CAPP), Western Powder River Basin (PRB), and Eastern CSX Transportation (CSX) coal futures.

Thanks for the replies, Euan and Dave,

I'm guessing then that we wouldn't see a particular year for global coal peaking with a concomitant price spike.

Presumably oil tends to spike more, sending the world into recession time and time again because there just aren't substitutes and it is so crucial to running economies. On the other hand, higher coal prices just tend to send utilities after natural gas and wind (more elasticity with coal?).

I'm simplifying a bit here because (U.S.) coal prices did rise quite steeply during the last oil spike, perhaps contributing to bursting the housing bubble and bringing on the recession? As one commodity goes, so do the rest it seems. But coal would be a lagging as opposed to a leading indicator, I'm guessing.

This analysis is deeply flawed.

There are good reasons why Hubbert linearisation may provide useful estimates of ultimate recoverable oil and gas. The logistic function is a simple (the simplest) representation of a unique, continuous scarcity process constraining growth. In global O&G, we understand the process well - most production is from giant fields that are geologically rare and unlikely to be replicated in future discoveries; scale is such that multiple smaller fields cannot replicate giant field production; most production is by straightforward multi-phase fluid flow to isolated well points, which cannot be greatly enhanced beyond physical limits. There are even decent arguments why a Gaussian linearisation might sometimes be superior (aggregation of multi-site production curves may be loosely analagous to the aggregation of the central limit theorem).

But coal is not like that. Sure, in certain regions, at certain times, scarcity processes will be at work that we should expect to result in behavior approximating a logistic (or Gaussian) model. But it is wrong to assume that those processes are stationary and immutable (as we think they are for conventional O&G). As I've argued before, the coal resources of this planet are poorly known and probably gigantic. It is naive to assume that, in the absence of meaningful energy alternatives (and in the absence of economic collapse*), they will not be exploited; exploited following scarcity processes very different to today's. Of course, Work Return on Work Invested (not EROEI) needs to be significantly > 1, but that is not an issue at the depths in my example (typically < 500-1000 m).


(* The only really likely reason, given what we know to expect from conventional O&G depletion.)

the coal resources of this planet are poorly known and probably gigantic.

Heck, Alaska has 2-5 trillion tons of coal, and very likely has at least 200 billion which are "technically recoverable" (a 200 year supply for the US). And, yet, it's not being used at all right now, because it's significantly more expensive than lower-48 coal. I think David Rutledge agrees:

Stuart Staniford: "Here's a link on the North Sea -
3 trillion tons down there, none of it currently counted in proven reserves (itself 800 billion tons of coal according to BP). Humanity currently emits about 8 ish GT/year of C. So the near term peak coal thing requires making assumptions like no-one will ever figure out how to get any appreciable fraction of that stuff out of the ground, and to me that's a very questionable assumption. "

Closer to home, the Illinois Basin has 150 billion tons which are being ignored right now because of a relatively small cost differential due to sulfur content. Analysts like the Energy Watch Group take a superficial look at production statistics, and declare that Illinois coal has peaked - that's unrealistic.

Furthermore, there's a lot of stuff that can and will be burned to generate power, if needed. We often dismiss "oil shale" as a source of oil, but it's an enormous source of easily burned fuel for electrical generation.

Unfortunately, we have enormous amounts of burnables, and we won't run out any time soon. We will have to make a conscious choice to leave them in the ground.

Fortunately, I think this is both possible and likely. For instance, coal consumption in the US dropped 10%in 2009 ( ) due to a combination of reduced electrical demand and increased wind and gas generation.

You have to base arguments on a discovery model first and foremost. Production only happens after discovery and since coal grades can range from lignite to anthracite (some people even claim peat is a form of very low-grade coal), we have a lot to pick over.

You mean that, for O&G, we should come to ultimate recoverable via a discovery model first, and look to build depletion models (logistic or whatever) around that. Fair enough. We can't produce what isn't discovered, and discovery vs. time seems to be pretty well-behaved (and so arguably predictable), despite massive technological change. The point is that for O&G, discovery is seriously difficult, because only very special combinations of geological circumstances result in significant producable accumulations. The rarity of suitable accumulations governs the answer.

Again, coal isn't like that. In developed countries at least, we know where the coal is, geologically speaking. Even where a given seam isn't specifically "discovered" yet, we know that rock unit x typically contains y percent coal distributed in seams of a certain thickness and character. And we know pretty well where that rock unit occurs, at what depth, in what stratigraphic and structural arrangements. We also generally know what grade of coal it'll contain, and what typical ash and sulphur contents to expect. All before that coal is actually "discovered".

So while I'd concur that arbitrary depletion curve fitting (logistic, Gaussian, multi-stage, whatever) isn't the right way, the discovery models of peak oil practice aren't it either. Actually, I'd suggest that the sort of geological models that have been much-derided in peak oil theory are likely to give the best answers in coal.

It would be nice if you had some references to your own or someone else's work.

Which is fair enough. "Extraordinary claims require extraordinary evidence" (Sagan). But it ain't me here claiming that the seminal multidisciplinary scientific effort of our time is fatally flawed (the IPCC, via the SRES scenarios). That is our good Professor of Electrical Engineering; the one doing arbitrary curve fitting apparently sans physical understanding. And the one with the obvious "sceptic" axe to grind (slide 39 onwards).

Nick has given a couple of North American examples. I can't help with that, but I can with my example. One needs a basic understanding of modern coal geology, which isn't available from a few blog-friendly refs. I'd start with a couple of these:

Great Artesian Basin: here
(There is a better one, can't locate right now.)

Queensland coal: here
(Around a third of the GAB is in this state; ref has a good discussion of what "reserves" actually means for coal.)

Walloon Coal Measures: here
(A major coal-bearing unit. Note that the Surat and Galilee Basins are sub-basins of the GAB)

Local coal seam gas background: here
(What the CSG industry is up to; the best recent source of information on sub-economic steaming coal occurence, not all public.)

...and it really does extend all the way to South Australia: here
(The coal-bearing unit they're studying is named after a town where it outcrops, 1500 km away in Queensland.)

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I am actually open to a debate about global coal resources / reserves, and am not 100% convinced that Dave's analysis provides the full picture. Its a pity that you and some others here don't know how to conduct civil discourse.

Wise counsel as always Euan. You have chided my rudeness before. It seems that our cultures differ.

I ask you just this. Is it not reasonable that TOD readers should know of your poster's publicly-stated sceptical position vis a vis global warming, to which I linked?

Every continent seems to have large deep and remote coal deposits. Some think in situ gasification will extract that carbon when conventional mining is unviable. However UCG is not going so well in places and the prospects don't look good.

In some countries there is talk of serious financial penalties for CO2 release. Suppose minemouth sub-bituminous coal cost $20 a tonne to produce. Now suppose carbon tax was $25 per tonne of CO2. Using a factor of 2.4 (not the 2.86 mentioned upthread) that tonne of coal will cost another 2.4 X $25 = $60 of carbon tax. That quadruples the effective cost from $20 to $80. Some say much higher carbon taxes will be needed to make carbon sequestration economic or to give a clear advantage to gas generation. That's combined cycle gas without carbon capture and storage CCS. This is why there is no chance of serious carbon taxes in coal dependent nations like Australia.

However even the talk of carbon taxes has created paralysis among utility companies. If they build a coal plant now without CCS they could be financially crippled if the carbon tax comes in some years later. In Australia Big Coal seems to be saying let's build now and add CCS later while cleantech is saying we want carbon taxes now. I think Big Coal will win this round only to find Asian demand makes coal expensive anyway.
Mines hit hard by heavy rainfall
By Debra Nowland
Updated Tue Dec 7, 2010 9:56am AEDT

"The early start to this year's wet season could put mines at risk (ABC News: Paul Robinson)

In central Queensland, coal mines look more like dams, and in some cases flooding has disrupted operations since September.

Mining companies say they are now re-assessing whether they can meet their export orders, but the mining union is accusing them of poor planning....
In recent years, coal companies have been living in a bit of a fool's paradise, we've had more than 10 years of drought," he said. "The older, wiser heads, that knew about how to set open cut mines up with water management ... have retired," he said.

"The double whammy is that they don't have their mining operations set up to deal with the wet weather," he said.

"So they not only lose production, but they also lose time having to clean their operations up and get them back into running order before they can get back into production mode."

A major environmental risk is the run-off from flooded mine sites.

Mr Roche says the water has nowhere to go and wants authorities to be flexible with its release.

"Not to introduce any environmental harm to the state but to deal in a pragmatic way with huge amounts of water built up in dams, which could be perhaps put into flowing water courses without any environmental harm," he said.

If the rain is partly due to AGW this could be blowback from Mother Nature.

Let me see now we have had 10 years of drought because of AGW. Now we have to much rain, because of AGW. I think I will apply for a grant of say $250,000 to study this dangerous phenomenon, and it if I can show that AGW is causing these weather disasters maybe I can get another $250,000 grant to find ways the government can mitigate these disasters. Great business plan : ).

Part of the funding for my PhD (a long time ago, I am retired now) came from the gas industry who were worried than the conversion of the domestic gas supply from town gas to natural gas was irreversible and that they needed to be able to make methane from coal after the North Sea reserves were exhausted.

Their opinion at that time was definitely that the reserves were still there, and could be brought into production if there wasn't a cheaper source of energy. The coal industry (also nationalised at that time) definitely considered itself to be in decline and my dealings with them were more along the lines of technology that could be used with imported coal, rather than british coal.

So I think the characterisation of Britain as being pretty much mined out is fair, and it is ineresting to see just how close the estimates made 150 years ago were. I would say a 3-fold overestimate, when the context required an over rather than an underestimate, was an extremely good prediction to make in 1861.

I am curious to know how good a curve fitted to the pre-1861 data would be. Dropping back 15 years and seeing no great variation isn't all that compelling because that is still well after the decline had set in. A good fit with the eventual outcome based on the pre-1861 data would be. The basic problem with curve fitting techniques is always that they are fine for interpolation, but extrapolation fails unless the decline is already obvious.

Also, while it is reasonable to treat oil as independent from coal, I doubt the reverse is true. Oil has a large demand that cannot be easily substituted by other energy sources, so analysing it in isolation is reasonable. Coal doesn't. Its production depends not only on the availability of coal, but also on the availability of other fuel supplies. I think you need to consider the reserves of coal plus all more easily utilised fuels together, rather than coal on its own. Going back where I started, coal use was run down in Britain because gas became available, and the contingency plan then was to manufacture gas from imported coal after the local gas reserves were exhausted.

Finally, once again going back to 1861, the estimates made then assumed deeper and thinner seams would eventually get mined, than actually have been. What happens if the experience of the geology that actually did get mined in a depleted region like Britain, is used to refine global estimates of reserves? How does the figure that gives stack up against the curve extrapolation?

Hi hot air,

Thank you for your thoughtful comments. The curve fit for long-term production for the UK does not really stabilize until around 1890. For most regions, it goes off the graph on the high side if you push back to far. You have to let enough of the s-shape develop before you can really do the fit.

Your final question is very interesting. I do not know the answer. I agree that the early reserves study in Hull's "The Coal Fields of Britain" was of high quality. The only conclusion I have been comfortable drawing is that we should be able to take the reserves as a loose upper bound for future production, and this is consistent with the current curve fits. There may be a region or two that will bust through the reserves, but I think it is quite unlikely that the world will ovrrun its reservs.


Also, while it is reasonable to treat oil as independent from coal, I doubt the reverse is true. Oil has a large demand that cannot be easily substituted by other energy sources, so analysing it in isolation is reasonable. Coal doesn't. Its production depends not only on the availability of coal, but also on the availability of other fuel supplies. I think you need to consider the reserves of coal plus all more easily utilised fuels together, rather than coal on its own.

The portability of energy dense oil is astounding, but electricity transmits well is becoming portable as well. It is not easy to substitute for the immense amount of generation that is powered by coal in 'little' markets such as the US and China. The availability of other fuel supplies to keep the oil flowing is taken as a given--coal is the biggest single such fuel supply. See how well treating oil as independent from coal works out if all coal generation ceased with the flick of a switch. The interdependence is strong and treating oil in isolation is probably more convenient than reasonable.

So we have two issues: essentially how much recoverable coal there is, and how much is point of no return or at least very serious damage from climate change perspective. It seems that the latter number (as currently known) is lower or similar to the former. If we recover recoverable coal (and add gas and oil), we will simply cook the Earth? Prettty much regardless of the model?

So we have no choice but to leave carbon underground in any case. Yes, from scientific,geologic and economic standpoint it is good to know, but from practical standpoint we already have all we should use?

As they say the discussion is academic?

No, the discussion is not "academic." We are going to burn the coal and cook the planet. The desire to maintain economic growth (especially in China) will trump concerns about greenhouse-gases causing global climate change. I do not like this situation--but that is the way it is.

Actually, China is the one place where geological Peak Coal in the near term seems possible to me: they're producing a much, much larger % of their official reserves, and we don't have very good info on their reserves.

I think that we could burn a lot more coal in the rest of the world, and we would if necessary.

On the other hand, Dave Rutledge is documenting coal Peak Demand. Given the availability of reasonably priced NG, wind, solar and nuclear, I think he may be reasonably on target.

Would have been better had you said. "We are going to burn the coal and raise CO2 to 450 ppm". The rise from 280 ppm (pre-industrial) to 455 ppm = a rise of 0.017%V. Cooking is conjecture.

Here's a pic from earlier this year outside of UK MET office (where the Hadley Center is). That's me on the right, Dave centre and Chris Vernon left - Dave and Chris are both very tall! Dave and I had both given talks on emissions scenarios, climate change and energy policy. Chris came along to listen.

I sit corrected; you are right, cooking is just a conjecture. My big point, however stands: Concerns about the environment are not going to curtail the further exploitation of coal. I also expect CTL to greatly increase the demand for coal over the next twenty years. Sasol has been making good profits for decades; there is no reason why other countries (such as the U.S.) cannot go to CTL on a large scale--provided that environmental concerns are brushed aside.

I agree with your big point which is that no matter what great aspirations the UN has in its "climate negotiations" that global economics will rule the day and we will burn what we can burn subject only to the rules of evolution.

I'm very concerned though by wrong thinking. There are rafts of data there to be interpreted. I'm concerned at present how wrong interpretations are cast upon data sets and how this leads to wrong energy policies?

Would have been better had you said. "We are going to burn the coal and raise CO2 to 450 ppm". The rise from 280 ppm (pre-industrial) to 455 ppm = a rise of 0.017%V. Cooking is conjecture.

So are Dave's estimates.

I'm very concerned though by wrong thinking.

As am I and others, namely that of Rutledge, Aleklett, et al. From CuriousCanuck below, "But if we emit 8GT of carbon, per year, and each ppm is 2GT, that means that 500GT of coal is equivalent to 130ppm. That puts the atmospheric CO2 above 500 ppm (minus absorption mechanisms). But there is also gas an oil, so for practical purposes we can't burn even half of these reserves."

If his/her numbers are correct, then 520 ppm would be achieved from coal alone. CO2 largely stays in the atmosphere for thousands of years, so the effects are very, very long-lasting. Hansen and Karecha (2008) found that just 110 gigatons of additional coal use would lead to @450 ppm CO2 and that that was excessive. Yet, you and Rutledge are saying we could burn all the coal and still have no problem.

By what logic or rationale do you dismiss Hansen's work?

I challenge you and Dave to step away from climate scenarios and rationalize your argument that the actual physical changes we are seeing at CO2 levels well below those you are stating are not dangerous.

You are basing your arguments that climate cannot be changed enough to really worry about on what you perceive models to be saying, but that is not climate science. To properly assess the risk of burning fossil fuels one must look at the changes we see already, understand there is about 1C still going to happen regardless of emissions, then add any additional heating brought by future emissions.

What all this means is a rise in temps of @ 3C from pre-industrial if all reserves are used, and that is conservative.

By whose analysis do you consider 3C to be a safe bet given all the effects of the worst case scenarios are already being measured?

And this:

“During the Middle Miocene (the time period approximately 14 to 20 million years ago), carbon dioxide levels were sustained at about 400 parts per million, which is about where we are today,” Tripati said. “Globally, temperatures were 5 to 10 degrees Fahrenheit warmer, a huge amount.”

Tripati’s new chemical technique has an average uncertainty rate of only 14 parts per million.

“We can now have confidence in making statements about how carbon dioxide has varied throughout history,” Tripati said.

In the last 20 million years, key features of the climate record include the sudden appearance of ice on Antarctica about 14 million years ago and a rise in sea level of approximately 75 to 120 feet.

“We have shown that this dramatic rise in sea level is associated with an increase in carbon dioxide levels of about 100 parts per million, a huge change,” Tripati said. “This record is the first evidence that carbon dioxide may be linked with environmental changes, such as changes in the terrestrial ecosystem, distribution of ice, sea level and monsoon intensity.”

Yes, 450ppm leading to runaway warming is conjecture, and scare mongering at that.

But if we emit 8GT of carbon, per year, and each ppm is 2GT, that means that 500GT of coal is equivalent to 130ppm. That puts the atmospheric CO2 above 500 ppm (minus absorption mechanisms). But there is also gas an oil, so for practical purposes we can't burn even half of these reserves. So even if there are trillions of tons of does not matter. We can't touch it.


But, this puts the problem with coal in the area of AGW, not freezing in the dark.

"We can't touch it."

Well, yes we can touch it. But we are told that we really shouldn't touch it for our own good. If we do touch it, it will be really bad, like eating that first apple. So, it would be really nice to be able to believe that the coal isn't really there at all. But we also can't talk about why we would like to believe it isn't there, which kind of clouds the issue of what the issue under discussion is. My sense of human nature is that we will touch it, and rational discussion will not delay this future.

I give you the following prophecy. You could write down the date if you wanted, but I am not the first to say this:

Peak Fossil Energy will happen.
Economy will go down the sink.
People will blame enviornemntal regulation.
People will stop to believe in climate/enviornmental sciences.
We will burn everything we can afford.
Then we enter climate spiral collapse.

This prophecy is based on one rule of human behaviour: "When a man has to chose between a loaf of bread and a soap, he choses the loaf". Base needs have a higher priority than luxury. Worrying about the future is a luxury we presently can afford, but in the future wont.

Dave's estimates for CO2 emissions include coal, oil and gas.

As indicated up thread I am not going to permit a debate here about the impacts of CO2 on climate change. Some may want to allege links between CO2 and what are viewed as anomalous climatic events. Personally I'd point to the geological record for the last 10,000 years which shows cyclic, rhythmic shifts in the pattern of the Indian Ocean Monsoon - and as a geologist I have faith in what the geological / isotope geochemical record tells me.

Discussing fossil fuel constraints on CO2 emission scenarios is on limits, speculating about the impact of CO2 on climate is not. If you want to discuss climate change please go do it on another blog.

Some readers might get the impression that a post that calls someone else's position as "conjecture" as an invitation to debate. If you do not want AGW comments, state so explicitly up front, and don't take a position yourself.

Now back to coal resources. "The stone age did not end for lack of stones." Neither will the "coal" age.

Natural gas is thrashing coal in several markets, and will likely continue to do so the next 10 years or more. This is easy to explain. Natural gas is now very low-price, there is now a global trade in LNG, a natural gas power plant is cheap and fast to build, and there is every indication of natural gas abundance the next 10 years or more. And natural gas has none of the criteria pollution of coal, apart from a bit of NOx. So watch now as the EPA turns the pressure on coal:

...New and emerging EPA regulations are going to force a huge wave of coal-plant retirements.

"The EPA regulations will tighten limits of emissions for sulfur dioxide, nitrogen oxides, mercury, and other toxics, possibly restrict coal ash for the first time, and possibly require cooling towers (so that wastewater discharge doesn't fry river and stream ecosystems). Oh, and there's also those pending greenhouse gas rules, though their influence will be somewhat less in the short term.

A couple of new reports have filled out more details on these coal-plant closures. Here's a sampling of recent MSM headlines:

The New York Times: "Utilities shift to gas-based plants as alternative to coal"
Wall Street Journal: "Utilities are increasingly looking to natural gas to generate electricity"
Financial Times: "Wave of closures set to hit U.S. coal stations"
Denver Daily News: "PUC approves retiring Denver-area coal-fired plants, switching to natural gas"
Reuters: "Xcel to shut or convert Colorado coal power plants"
Chattanooga Times Free Press: "TVA to shutter coal plants, turn to nuclear"
Times Daily: "TVA to idle coal plants to cut emission output"
Charlotte Observer: "Duke considers closing old coal plants"
I could go on.

Two new reports investigate just how big the wave of closures will be. One is from the investment bank FBR Capital Markets, which Reuters covers in a press release. Another is from consultancy The Brattle Group. Brattle's report digs into the upgrade-or-retire decision every coal plant in the U.S. will soon face, using a "retirement screening tool," and concludes that ...

... emerging EPA regulations on air quality and water for coal-fired power plants could result in over 50,000 MW of coal plant retirements and require an investment of up to $180 billion for remaining plants to comply with the likely mandates...

Some readers might get the impression that a post that calls someone else's position as "conjecture" as an invitation to debate. If you do not want AGW comments, state so explicitly up front, and don't take a position yourself.

I think this is fair comment. But what is the main point you are trying to make in the remainder of your post? In the UK, many large coal fired power plants are due to close. There is no serious plan as yet that will assure the stability and availability of our future power supplies. Wide spread suffering of the population, in particular the poor and elderly is just around the corner.

Decarbonizer is looking at it from the perspective of the US, which now has a large surplus of shale gas as a result of recent technological innovations. So, despite the fact that the US has the world's largest reserves of coal, it is economic for the power utilities to switch to natural gas as their coal-burning plants get old. This can be done very cheaply and quickly because NG fired power plants are cheap and quick to build, and existing coal burning plants can be converted to NG relatively easily. However, the whole transition hinges on the availability of large quantities of cheap gas.

For the UK, the situation is completely different. Its coal reserves are largely exhausted and its coal production peaked generations ago. Now that its North Sea gas reserves are half-exhausted and production has started to decline, it needs a new source of energy. It should have seen this coming and started to plan for it 10-20 years ago. I can't see "renewable" sources coming on-stream fast enough and cheaply enough to make much difference. So, apparently the people are just going to have to suffer through shortages and blackouts. They've had to do this before, but there was a war involved that time.


So you are not going to permit climate debate but you would put forth your belief that natural climate cycles are responsible for the erratic weather events?

Why such a huge disconnect there? You love to analyze climate changes -- it may be your one true passion in life.

It is interesting to consider your regression (or progression depending on your ideological worldview) from this earlier comment of CryWolf:

Today we are in a new ball game where man's combustion of fossil fuels has uppset the equilibrium - forcing climate change at a time in the cycle that is already a warm inter-glacial phase.

Since that time it is like you have found a religion in denialism -- exactly like that of Christians that I have personally watched being born again. Evolution and the greenhouse effect have so much in common in that respect.

I am a doomer because of mass delusion not because of finite resources.

Its amazing how folks manage to recall and dig up these old comments:-) Its true that before i began to read quite widely on climate related topics that I simply accepted what I was told. Now I have formed an independent view based upon what I regard as evidence.

And yes its true that my view is that natural climate cycles play a more significant role than currently accounted for in GCM's and what I would like to see is more work done examining the impact of Man upon this natural rhythm.

Much as I would enjoy a reasoned debate on this topic its just not possible to have that here as the language you choose to use clearly demonstrates.

Its near the end of this post's active life so I will ask a climate question almost straight out but will tie it to energy just a little. I've looked about some to see what I could find on how often and how recently the arctic ice cap has disappeared in the summer--this does affect what is classified as coal reserves so it actually is kind of on topic ?- ) Nothing that I'd call concrete has come to my eyes. I was wondering if you have found any good work on that specific topic? I'd appreciate some good leads-emailed if including them here is out of line. Thanks for the post--I can't even imagine how much time being a regular contributor, much less editor, at TOD takes.

A good source for such info:

This could be what you are asking for

The current reduction in Arctic ice cover started in the late 19th century, consistent with the rapidly warming climate, and became very pronounced over the last three decades. This ice loss appears to be unmatched over at least the last few thousand years and unexplainable by any of the known natural variabilities.


Persistent Solar Influence on North Atlantic Climate During the Holocene
Gerard Bond,1* Bernd Kromer,2 Juerg Beer,3 Raimund Muscheler,3 Michael N. Evans,4 William Showers,5 Sharon Hoffmann,1 Rusty Lotti-Bond,1 Irka Hajdas,6 Georges Bonani6


The history of sea ice pulses in the North Atlantic over the last 10,000 years is extremely complex, but is written into the geological record for those who have been trained to read it.

I apologise.
I should have made it clear to Luke and to anybody else that I have no personal expertise relevant to the subject of the history of arctic sea ice. It is not my area of science. Nevertheless I am interested in the science in the article that I pointed to, History of sea ice in the Arctic, published in Quaternary Science Reviews 29(2010)1757–1778. I hoped Luke would also find the article, and the apparently recent evidence, interesting.
I must agree with you of course in general, that in complex areas such as this, one must continue to live with uncertainty.

1. Research is 10 years old. There is better info on solar forcings.

2. Research is regional.

3. Solar forcing are accounted for in GCM's and are an important, but small percentage and well-known.

4. There is nothing in that paper that is inconsistent with current conditions.

5. Nothing in that paper explains away even one of the many, many changes we see. Shall I list the dozens, even hundreds of changes we are seeing? The glaciers, out-of-sync ecosystems, declining ice - everywhere, polar amplification, acidification, plankton die off.... and so much more.

The evidence is there for those who will look at it. Picking one metric and pulling up one out-of-date paper that doesn't even say what you seek to imply it does is not convincing.

Thanks Phil, quite recent, very much what I was looking for--after I get through this one I'll look into the 2001 article Euan suggested.