A new NASA study this week shows the potential impacts of the warming climate on the occurrence of “megadroughts”, which are multi-year extreme droughts that have historically affected areas like California and the central part of the US. (Tree ring analysis has shown that the Southeast has also experienced megadroughts in the last 500 years.) Analysis of tree rings and computer simulations of future climate under a variety of conditions shows that it is likely that these long and severe droughts are likely to become more frequent in the future, leading to significant negative impacts on agriculture and society in those regions.
In the past, megadroughts in the Southwest have been linked to the migration of native people away from those areas due to lack of water. The 1930s Dust Bowl is one example of what a mega-drought might look like, although results show that megadroughts lasting 20 years or more are much more likely than in historical records based on tree rings as well as model simulations.
You can read the NASA news story with some videos here. Bloomberg Businessweek also has an article which discusses some of the implications on businesses.
In the Southeast, soil dryness is expected to increase more slowly than in other parts of the country due to our access to moisture for rain from the Gulf of Mexico and the Atlantic Ocean, but droughts are still expected to become more frequent as temperatures continue to increase.
