Warming Is Increasing Hurricane Activity
Illustration by:Matt Mahurin
A paper published yesterday in Nature for the first time measures the contribution of rising sea surface temperatures to changes in hurricane frequency and intensity. The authors found that about 40 percent of the increase in Atlantic hurricanes between 1996 and 2005 –in comparison to the average over the 1950-2000 period–is due to the heat of the sea surface–about 0.5 degrees centigrade on average. In the past, it’s been argued that changes in near-surface trade wind speed were the cause of increased hurricane activity. The British authors of the study, Mark Saunders and Adam Lea, do not claim that their analysis can establish whether global warming is responsible for the increase in sea temperatures. But it seems likely that it is, at least partly. The only other explanation is something called the Atlantic Multidecadal Oscillation. The latter is a hypothetical natural cyclic shift in the ocean’s temperatures.
According to the 2007 Fourth Assessment Report of the Intergovernmental Panel on Climate Change, it is “more likely than not” that manmade climate change has contributed to hurricane intensification since the 1970s. The IPCC also predicted that as the earth and seas continue to grow warmer, hurricane winds and rainfall will continue to grow more intense.
Worldwide, the number of strong hurricanes and cyclones has increased by 75 percent since 1970.