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His basic premise is that, with the controls we are likely (not) to put in place, temperatures will rise 8*C in the temperate zones and 4*C in the tropics by 2100.  He notes the effect that particulate emissions are having at present in reducing solar heating and notes that it can and probably will disappear well before then.  I recall a PBS program, NOVA, I believe, that addressed the particulate emissions issue and made a comment this time last year.  Turned out poemless had written a diary on the subject the year before and I had been watching a re-run.  Most of the estimates I have seen predict 6C increases if we do little.  None of them, to my knowledge, include the present moderating effect of industrial haze on greenhouse temperature increases.

The rest of Lovelock's conclusions deal with his estimates of the impact of these changes.  I do not believe any "serious" person or organization has yet published an analysis of the impact of such changes on the carrying capacity of the planet.  I do recall a comment by asdf regarding the extenction of species as climate change proceeds faster than species can adapt.  Given our species' known aversion to bad news, I would be reluctant to write off Lovelock's analysis out of hand.  We do know that the Pentagon and the CIA are taking these issues seriously.

"It is not necessary to have hope in order to persevere."

by ARGeezer (ARGeezer a in a circle eurotrib daught com) on Fri Aug 21st, 2009 at 05:52:51 PM EST
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The effect of particle emissions is not as great as Lovelock assumes.

A 6.4 degree Celcius rise in 2100 is the top of the range of likely warming for the most fuel-intensive scenario in the fourth IPCC assessment report. I don't think it's going to happen because we're not going to get that scenario, although it could be possible if there is a runaway warming effect.

by nanne (zwaerdenmaecker@gmail.com) on Fri Aug 21st, 2009 at 06:22:01 PM EST
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But then he is only 1.6C above that worst case and he is a single concerned individual whereas the IPCC is a consensus report from a large group.  And he only refers to +8C for the temperate zones, with +4C for the tropics.  Is the IPCC +6c figure for an earth average?  If so, they could be saying the same thing.  Either way, I certainly hope we can hold the overall average to something like +4C.  That would be bad enough.

"It is not necessary to have hope in order to persevere."
by ARGeezer (ARGeezer a in a circle eurotrib daught com) on Fri Aug 21st, 2009 at 09:30:56 PM EST
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The IPCC makes its estimates by 1) setting scenarios and 2) evaluating predictions of a range of models on these scenarios. This results in a 'likely' range on its fossil fuel intensive scenario between 2.4 and 6.4 degrees celsius, with a best estimate on that scenario of 4 degrees celsius.

So this is the upper bound of the likely range for the scenario with the highest emissions. In other words, Lovelock is assuming the worst case rather than the most likely.

That's his right, of course. But it would be silly to start taking it as the most likely picture of what's going to happen rather than a worst case possibility.

by nanne (zwaerdenmaecker@gmail.com) on Sat Aug 22nd, 2009 at 04:16:15 AM EST
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But it would be silly to start taking it as the most likely picture of what's going to happen rather than a worst case possibility.

Agreed.  Yet, at this point it seems to me very unwise to minimize worst case possibilities.  People should keep in mind that such an outcome IS as possibility.

"It is not necessary to have hope in order to persevere."
by ARGeezer (ARGeezer a in a circle eurotrib daught com) on Sat Aug 22nd, 2009 at 10:09:39 AM EST
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... burn all the coal we can dig up or buy from somewhere around the world until its all finished, even if there is less oil available than assumed in some of the high fossil fuel scenarios, that's still awful close to the top end of the high fossil fuel scenario.

We are presently on track for very near the worst case, and will stay there until we show a capacity to leave coal in the ground unconsumed.


I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.

by BruceMcF (agila61 at netscape dot net) on Tue Sep 15th, 2009 at 10:15:36 PM EST
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