After 2008's spate of deadly hurricanes - Gustav, Hanna, and Ike - massive flooding in the Midwest, and severe droughts in the Southeast early in the year, you may be wondering whether these extreme weather events have anything to do with climate change.
If so, you're not alone.
Global warming causes both floods and droughts
Flooding
In June, the U.S. Climate Change Science Program issued a report predicting an increase in extreme weather in North America, including both floods and droughts, as a result of climate change. There is strong evidence that that heavy downpours, such as those that affected Missouri and Iowa this year, will become more common and more severe along with the rise in global temperature.
Droughts
But what, you might ask, does this have to do with droughts? As director of the National Climatic Data Center Thomas Karl explains, "When it rains, it rains harder and when it's not raining, it's warmer - there is more evaporation, and droughts can last longer." [1]
The effect on hurricanes
The evidence on hurricanes is more mixed. Some scientists have hypothesized that warmer ocean surface temperatures will lead to an increase in hurricanes and tropical storms, but this may not actually be the case.
Hurricanes may become less frequent as the temperature of the Atlantic Ocean rises, suggests a recent study in Nature Geoscience. However, the study, which relies on historical weather data and computer simulations, does suggest that heavy rainfall may increase from storms that do not reach tropical storm status. [2]
