Extreme drought ahead for US.

From LiveScience:

Extreme drought is likely in store in the coming decades for parts of the United States and the broader Western Hemisphere, scientists said today (Oct. 19), cautioning that we should expect dry conditions unlike anything seen in modern times.

The likely culprit: warming temperatures linked to climate change.

"We are facing the possibility of widespread drought in the coming decades, but this has yet to be fully recognized by both the public and the climate change research community," said National Center for Atmospheric Research (NCAR) scientist and study team member Aiguo Dai. "If the projections in this study come even close to being realized, the consequences for society worldwide will be enormous."

Droughts can be associated with significantly reduced precipitation, dry soils that fail to sustain crops, and reduced levels in reservoirs and other bodies of water that can imperil drinking supplies.

However, Dai cautioned that the findings are based on the best current projections of greenhouse gas emissions. What actually happens in coming decades will depend on many factors, including actual future emissions of greenhouse gases as well as natural climate cycles such as El Niño.