Tuesday, March 02, 2010

Now come the hurricanes

Nature Geoscience came out with findings that differ from the 2007 IPCC Report (and differ then with Al's) on the link between hurricanes and anthropogenic global warming. Slowly but surely.

Here's a summary from Nature:
Whether the characteristics of tropical cyclones have changed or will change in a warming climate — and if so, how — has been the subject of considerable investigation, often with conflicting results. Large amplitude fluctuations in the frequency and intensity of tropical cyclones greatly complicate both the detection of long-term trends and their attribution to rising levels of atmospheric greenhouse gases. Trend detection is further impeded by substantial limitations in the availability and quality of global historical records of tropical cyclones. Therefore, it remains uncertain whether past changes in tropical cyclone activity have exceeded the variability expected from natural causes. However, future projections based on theory and high-resolution dynamical models consistently indicate that greenhouse warming will cause the globally averaged intensity of tropical cyclones to shift towards stronger storms, with intensity increases of 2–11% by 2100. Existing modelling studies also consistently project decreases in the globally averaged frequency of tropical cyclones, by 6–34%. Balanced against this, higher resolution modelling studies typically project substantial increases in the frequency of the most intense cyclones, and increases of the order of 20% in the precipitation rate within 100|[nbsp]|km of the storm centre. For all cyclone parameters, projected changes for individual basins show large variations between different modelling studies.

Full report needs subscription though. But read here and here; all the same, the UN IPCC is fast losing more credibility.

“We have come to substantially different conclusions from the IPCC,” said Chris Landsea, a lead scientist at the American government’s National Hurricane Center, who co-authored the report.

He added: ”There are a lot of legitimate concerns about climate change but, in my opinion, hurricanes are not among them. We are looking at a decrease in frequency and a small increase in severity.” Landsea said he regarded the use of hurricane icons on the cover of Gore's book as "misleading".
Of course they've said an independent review will take place. Ya sure.

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