Under the auspices of the World Meteorological Organization’s Commission on Atmospheric Sciences, its Tropical Meteorology Research Program Panel has just issued a statement on hurricanes and global warming (here in PDF).

The statement is significant not only because it was drafted by nine prominent experts, but because it includes in its authorship Kerry Emanuel, Greg Holland (second author of Webster et al. 2005), Ton Knutson, and Chris Landsea. Frequent readers will recognize these names as people not always in agreement. That they came together to produce a consensus statement is good for the community, and also gives a good sense on where they agree and disagree.

While the statement has enough background and language to allow anyone to selectively cherry pick from it in support of any perspective, here is the take-home message from the statement

“The research issues discussed here are in a fluid state and are the subject of much current investigation. Given time the problem of causes and attribution of the events of 2004-2005 will be discussed and argued in the refereed scientific literature. Prior to this happening it is not possible to make any authoritative comment.”

Therefore, for those of us not involved in primary research on hurricanes and climate change, any conclusions, or predictions about how future research will turn out, about the role of global warming in hurricanes will necessarily be based on non-scientific factors. If you are like the IPCC, then you will assume that observed climate phenomena can be explained by natural variability unless and until the thresholds of “detection and attribution” can be achieved. This is a high threshold for identification of greenhouse gas effects on climate, and it is of course not the only approach that could be taken. But it is the approach of the IPCC.

If you are politically or ideologically motivated to use the threat of stronger hurricanes in pursuit of some goal, then you will bet that a link will indeed be established. And similarly, if you are politically or ideologically motivated to discount the threat of stronger hurricanes in pursuit of some goal, then you will bet that no link is immediately forthcoming.

The reality is that the present state of science does not allow us to come to a conclusion that global warming has affected hurricanes (e.g., see this PDF). It is suggestive, and different experts disagree about what future research will tell us. I’d bet that this condition of uncertainty about future research will be with us for a long time. Thank goodness its resolution is not of particularly large importance for understanding and implementing those actions known with certainty to be most effective with respect to hurricane impacts (e.g., here in PDF).