Global Science Report is a weekly feature from the Center for the Study of Science, where we highlight one or two important new items in the scientific literature or the popular media. For broader and more technical perspectives, consult our monthly “Current Wisdom.”
When it comes down to scaring people into accepting onerous reductions in carbon dioxide emissions, it’s always a good idea to trot out the specter of increased hurricanes, despite the lack of backing for this in the science literature.
“Bluster” isn’t the name of an Atlantic hurricane (although it would be a good one*), but rather our description of the stories about new research out of the Massachusetts Institute of Technology projecting an increase in the frequency and magnitude of hurricanes as a result of anthropogenic climate change.
Publishing in the Proceedings of the National Academy of Science, M.I.T.’s Kerry Emanuel projects a rather large increase in the global frequency of tropical cyclones as well as their intensity over the course of the 21st century.
Emanuel is the first to admit that the changes he found were largely of a different character to those in the generally accepted literature, which projects little change in the frequency of tropical systems (with perhaps even a slight decline) and only a slight increase in the future intensity.
The difference between Emanuel’s results and those from the bulk of other studies arises primarily for two reasons; 1) the future emissions scenario used to drive the global climate models; and, 2) the method of downscaling coarse climate model output to the finer scale necessary to model tropical cyclones.
When it comes to emission scenarios, Emanuel chooses to use the most extreme scenario, which more than triples the effective atmospheric carbon dioxide concentration by the end of the century, while most other studies have used a more modest scenario which leads only to about a doubling. With new technologies opening up vast abundances of lower CO2-emitting natural gas available for power generation, the extreme emissions scenario used by Emanuel seems unlikely.