Certainly the Clovis people in North America lived for only a very short time (about 1000 years I think) before becoming something else-- 13000 years ago.

There distinctive trademark was the large bladed stone spearhead.

It appears that at the same time a number of the North American super-mammals were extincted.

This would be consistent with the impact of the Polynesians on New Zealand-- again a wave of extinctions, including the Dodo Bird.

Current research is discounting hunting for these extinctions. Not enuf bone damage on found carcasses. It is likely that the food chain was disrupted by the turning of the mass grasslands North of 60 to tundra. Large parts of yukon and alaska known as Beringia were ice free for much of last ice age. Mammoths starved. Saber tooth had no prey. etc etc.

Jason: Your article is behind a paywall. Reading from the abstract, is it correct that the change in species composition lowers the above ground carbon sink?

I agree it is going to be damn hard to fix the problem, unless we come up with a magic bullet.

Hi Freddy,

My you do bring back the good old days of 1982 and arguing with my young wife about whether or not GW was 'a happening'...I would jump up and down and cry things like 'Hawaiian mountain tops' and 'radical CO2 increase' and she would smile and humour me, put cold cloths on my fevered brow...happy days, happy days.

You are quite right about the attitude then as a newly minted meteorologist friend of mine was not as simpatico and through clenched teeth would sternly say, "up at the Academy we consider GW just so much ballyhooo and nonsense".

I couldn't understand why no one was excited about this CO2 increase. I also did not understand why it took nearly a month after hearing about 'cold fusion' before I heard another word on the news about it. The Saviour had appeared it' seemed, and nobody give a cool god damn. So far 'they' were right about ignoring that one...win some loose some.

To muddy the waters, 1980 was clearly shown by science to be a peak in solar activity for the last 1000 years by all manner of proxies. There was no indication that "fighting GW" would not be a losing battle in light of possible very long term solar and orbital cycles.

Cite? AFAIK, there is no evidence of any sustained cycle in solar output, as long as we have been measuring it.

The price tag of IPCC 2001's mitigation effort was said to be about $600-Billion. Several g-20 Govt's were in Recession or flat growth at that time. Europe refused to identify the USA penalties that would be accessed against the USA, Australia and Canada should they not meet 2009 Kyoto Protocol targets. All three countries were already 20% higher in emissions instead of 5% below 1990 levels. There was little appetite to spend Hundreds of Billions of Dollars for an effort that was possibly agin the grain of Mother Nature's fate. Albeit we acknowledge that GHG was im play, only in the last two years has their been sufficient science to illustrate that Earth is not in a long term solar forced warming cycle.

Again a number of 'facts' that need checking, or seem just plain wrong, or need to be put in context.

$600bn *over time*. Not in one go.

$600bn in 2001 was roughly 1.7% of world GDP at that time. However GDP is a 'flow' number ie it is meaningless unless taken over a unit time (per annum).

Of course, Iraq and Afghanistan have cost the *US* alone, as much as that in the interim since then. Not to mention Homeland Defence.

On your 'only in the last 2 years' that amazes me. Where do you get those data for solar flux and forcings?

Further, as shown on the Climate venue of my website, albeit the Globe has been on this 0.6C warming trend, the USA in fact was on a cooling trend since the el nino of 1998. In 2004, it was 1.5F cooler than 1998.

Puzzled by this claim. The 11 hottest summers ever recorded in North America have all been since 1990, I believe. Now 1991 and 1992 were cold, because of Pinatubo (which Hansen's model predicted quite exactly).

So in those 16 years, you've just told us that the years, as a whole, were cooler 1998-2004. That leaves 1993,94,95,96,97?

While it is easy for leftist, socialist, liberal on-the-bandwagon, tree-hugger types to now say we coulda/shoulda/woulda ... they are plainly uneducated as to what was consensus during this timeline.

FWIW I never voted anything but the Canadian Tory Party. (I wouldn't vote for those right wing prudes though). So I resent the undertone that it is only leftists/ socialists or worse, liberals and tree huggers, that think that global warming is a problem.

In fact, the first world politician of stature to sound the alarm on global warming was none other than Margaret Thatcher.

I don't think Margaret Thatcher was a leftist, a soicalist, a liberal on the bandwagon, nor a tree-hugger.

Conservatives like trees too, I might add.

And how many on the bandwagon stopped 1949 M King Hubbert's efforts for us to go Nuclear power and hydro elec generation? How many of them wanted us to burn oil, gas and coal instead of uranium?

The governments of the world staged an accelerated programme to encourage nuclear power. See Robert Pool 'Beyond Engineering: How Society Shapes Technology' for an excellent history of the civilian (US) nuclear power industry and the government's role in 'kick starting' the industry.

I can tell you from the family experience of building CANDUs that government subsidy, not least on the question of nuclear waste, is an inextricable part of the history of civilian nuclear power (and hydro electric-- the issue of land rights and eminent domain alone, plus the time lags to finance and build).

There is better evidence. As soon as privatisation and deregulation took off in North America and the UK, the utility industry stopped building anything but gas fired stations.

And how many of the pro-GW emission cutters actually know the magnitude of cuts required in g-20 countries to meet kyoto protocol targets? Dick all. Neither politicians nor enviromentalists have been honest with that shopping list of "to do items".

Untrue. Completely untrue. Both assertions. Most environmentalists have a very good handle on how much CO2 we emit, and what our Kyoto Targets are.

What does it tell u when 98% of scientists believe in GW?? It tells me that only 2% of scientists are climatologists!!

1. you are misquoting. 99% of *climatologists* believe in global warming. I'm not sure if anyone has polled scientists as a whole.

I have little patience for recent bandwagon practioners. That is not to say that i do not appreciate the magnitude of the problem and the necessity of action plans. I am saying that very few are ready for the consequences of "today's fad of going green".

I think the problem is political. Scientists say we need to stop accumulations by 500ppm CO2, 550ppm at the worst. They have been saying that, pretty consistently, since the middle of the 90s. James Hansen has been saying it for longer than that, and whereas 18 years ago his models were seen to be 'way out there' they are now pretty close to consensus.

Economists have been saying that might be too expensive, or you cannot show that the damage is worth the cost of abatement. However the inputs have been garbage: they have assumed the base cases on global warming, without recognising the extreme costs and consequences of the highest costs.

The costs of stabilising the world at 550ppm range from minus 1 to plus 5 per cent. of GDP in 2050 (minus 1 meaning there is a net gain due to the creation of new industries to meeet the challenge of low carbon). The Stern Review credibly says it will be 1% of GDP. They do something called a Monte Carlo simulation of different possible cost scenarios.

Let's contextualise this. 5% of GDP in 2050 says that, in 2050, the world will have the GDP of January 2048, because it opted to do something about global warming, rather than pursue Business As Usual.

As an analogy, consider this. Edwards, Hillary Clinton et al have been asked for weeks why they supported the 21-day Iraq2 offensive. Each one admits to possibly being wrong, but state categorically that they made their decisions based on the "best information available at the time". The Climate Change debate is no different...

Actually the analogy is entirely false. Because you have this thing about 'liberals' you are trying to find an analogy that puts them in the worst possible light.

The Iraq decision was made on the basis of a conscious effort by the people presenting the information to filter and distort it in the worst light--that Iraq had WMD, that Iraq was somehow involved in 9-11. Difficult for a US politician to vote against war when his President tells him or her that Iraq has WMD which threaten the United States.

On global warming, the science has been in place since the early 1990s. What has changed has been:

1). there is more data (the hottest years ever recorded, plus truly alarming data on glaciation). As Hansen says, the anthropogenic global warming trend has decisively broken out of the background noise.

The best analogy I can come up with is when the hole in the ozone layer was discovered.

The political climate suddenly switched from 'do nothing, it's too expensive, it's not necessary, we don't know enough, we can't prove CFCs are doing this' to 'do something'.

You will spot the familiar conservative arguments about CFCs. When the hole in the ozone layer was discovered, that crashed.

2). the well organised disinformation campaign against global warming has begun to break up. Some of the world's leading companies (BP and Shell) abandoned it in the late 90s. Even Exxon is beginning to find it to be a political liability.

3). in the early 1990s, the public, if it thought about global warming at all, thought it was a long time away. It doesn't think that any more.

No, I mean Fig 5 (captions are below the figure).

VT - you had me going for a moment there.

It would be impossibly too expensive to do anything about it in any case.

I just wonder if this bit of your satirical rant may be perceived to be true. I get the feeling that in certain countries (like the UK) politicians are beginning to panic a bit - but without a world consenus to take drastic action, I don't think anything will happen. Equally, I don't think anyone actually knows what the consequences of GW are going to be.

I may have missed his subtle rhetorical point and I thank you for bringing it to my attention.

It seems to me the sobering lesson of this environmental crisis, as with so many previous ones (remember how Rachel Carson was treated? As an extremist, a woman without a Phd-- there was also an unsubtle undertone of anti-semitism, this was the early 1960s after all) has been that the 'extremists' usually have the right end of the stick, they are just 20 years ahead of the rest of us.

In the 30 or so years that I have been following current affairs, the 'extremist' environmentalist position has almost always become the received wisdom in the subsequent decade or two.

And the costs of meeting the 'extremist' pollution abatement have always turned out to be much lower than was feared or forecast.

20 years ago, the notion that we would ban PVC because it might be causing male sterility, would have been laughed out of the room.

And yet our studies of fish and amphibians now suggest that we will, indeed, have to ban PVC.

20 years ago, the notion that ground level atmospheric ozone was a serious pollutant was certainly a fringe one. Yet now, we have decent links to the rising incidence of asthma-- one of the most serious chronic ailments in the industrialised world.

Your problem in the usa with social security balancing is easy. Raise payroll deductions 2% and it balances 'til 2075 instead of 2045.

Same with gasoline taxes. Raise them to where Canadians are and join the rest of the world. Like metric! Phase in over five years if u wish.

But as with so many other unimplemented long term strategies, usa Elections get in the fricken way. Mid-term Elections were imminent. Let's hold off. Now we see that instead of rushing out and doing the "right thing" non partisan committees are going partisan 'cuz of the Presidential Primaries jockeying; and we will shortly hear that the 2008 Elections are again "too close" to make voters angry. The public is primed presently. But the politicians, imho, are afraid of the blowback of sticter regulations and restrictions on both the consumer and businesses.