The chronic drought that hit western North America from 2000 to 2004 left dying forests and depleted river basins in its wake and was the strongest in 800 years and it's still going on. Scientists have concluded that those conditions will become the "new normal" for most of the coming century. As bad as conditions were during the earlier drought, they may eventually be seen as "the good old days."
This is also bad for climate change: As vegetation withers, more carbon dioxide is released into the atmosphere, with the effect of amplifying global warming. Science Daily quotes biologist Beverly Law as saying, "Areas that are already dry in the West are expected to get drier. Climatic extremes such as this will cause more large-scale droughts and forest mortality, and the ability of vegetation to sequester carbon is going to decline. And if global carbon emissions don't come down, the future will be even worse."
Ordinarily, the land sink in North America is able to sequester the equivalent of about 30% of the carbon emitted into the atmosphere by the use of fossil fuels in the same region. However, based on projected changes in precipitation and drought severity, scientists think this carbon sink, at least in western North America, could disappear by the end of the century (that would certainly explain the Mayan 2012 prophecy--NOTE: Subscribers can still listen to this show.
The new study concludes that "Towards the latter half of the 21st century the precipitation regime associated with the turn of the century drought will represent an outlier of extreme wetness. These long-term trends are consistent with a 21st century "megadrought."