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Freeman Dyson’s selective vision

Filed under: — david @ 24 May 2008

In the New York Review of Books, Freeman Dyson reviews two recent ones about global warming, but his review is mostly shaped by his own rather selective vision.

1. Carbon emissions are not a problem because in a few years genetic engineers will develop “carbon-eating trees” that will sequester carbon in soils. Ah, the famed Dyson vision thing, this is what we came for. The seasonal cycle in atmospheric CO2 shows that the lifetime of a CO2 molecule in the air before it is exchanged with another in the land biosphere is about 12 years. Therefore if the trees could simply be persuaded to drop diamonds instead of leaves, repairing the damage to the atmosphere could be fast, I suppose. The problem here, unrecognized by Dyson, is that the business-as-usual he’s defending would release almost as much carbon to the air by the end of the century as the entire reservoir of carbon stored on land, in living things and in soils combined. The land carbon reservoir would have to double in size in order keep up with us. This is too visionary for me to bet the farm on.

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Tropical tropospheric trends again

Filed under: — gavin @ 24 May 2008

Back in December 2007, we quite heavily criticised the paper of Douglass et al (in press at IJoC) which purported to show that models and data were inconsistent when it came to the trends in the tropical troposphere. There were two strands to our critique: i) that the statistical test they used was not appropriate and ii) that they did not acknowledge the true structural uncertainty in the observations. Most subsequent discussion has been related to the statistical issue, but the second point is perhaps more important.

Even when Douglass et al was written, those authors were aware that there were serious biases in the radiosonde data (they had been reported in Sherwood et al, 2005 and elsewhere), and that there were multiple attempts to objectively address the problems and to come up with more homogeneous analyses. We mentioned the RAOBCORE project at the time and noted the big difference using their version 1.4 vs 1.2 made to the comparison (a difference nowhere mentioned in Douglass et al’s original accepted paper which only reported on v1.2 despite them being aware of the issue). However, there are at least three new papers in press that independently tackle the issue, and their results go a long towards addressing the problems.
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How to cook a graph in three easy lessons

Filed under: — raypierre @ 21 May 2008

These days, when global warming inactivists need to trot out somebody with some semblance of scientific credentials (from the dwindling supply who have made themselves available for such purposes), it seems that they increasingly turn to Roy Spencer, a Principal Research Scientist at the University of Alabama. Roy does have a handful of peer-reviewed publications, some of which have quite decent and interesting results in them. However, the thing you have to understand is that what he gets through peer-review is far less threatening to the mainstream picture of anthropogenic global warming than you’d think from the spin he puts on it in press releases, presentations and the blogosphere. His recent guest article on Pielke Sr’s site is a case in point, and provides the fodder for our discussion today.

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Climate Change and Tropical Cyclones (Yet Again)

By Rasmus Benestad & Michael Mann
Hurricane Katerina
Just as Typhoon Nargis has reminded us of the destructive power of tropical cyclones (with its horrible death toll in Burma–around 100,000 according to the UN), a new paper by Knutson et al in the latest issue of the journal Nature Geosciences purports to project a reduction in Atlantic hurricane activity (principally the ‘frequency’ but also integrated measures of powerfulness).

The close timing of the Knutson et al and Typhoon Nargis is of course coincidental. But the study has been accorded the unprecedented privilege (that is, for a climate change article published during the past 7 years) of a NOAA press conference. What’s the difference this time? Well, for one thing, the title of the paper: “Simulated reduction in Atlantic hurricane frequency under twenty-first-century warming conditions” (emphasis added).

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The Global Cooling Bet – Part 2

Filed under: — group @ 13 May 2008 - (Italian) (Deutsch) (Español)

Last week we proposed a bet against the “pause in global warming” forecast in Nature by Keenlyside et al. and we promised to present our scientific case later – so here it is.

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