_smoke on the Water: Freshwater Shortage Will Double Climate
Change’s Impact on Agriculture (Study)
-- a _kt75 | reprint 
_Experts expect global warming to have a negative impact on crop  yields, but shortages of water for irrigation could make for double the  trouble, according to a study published yesterday.
As described in ScienceDaily,  “given the present trajectory of greenhouse gas emissions, agricultural  models estimate that climate change will directly reduce food  production from maize, soybeans, wheat and rice by as much as 43 percent  by the end of the 21st century. But hydrological models looking at the  effect of warming climate on freshwater supplies project further  agricultural losses, due to the reversion of 20 to 60 million hectares  of currently irrigated fields back to rain-fed crops.”
The study’s lead author, Joshua Elliot, said the analysis is the  first of its kind to feature an in-depth comparison of agricultural and  hydrological models, which resulted in dramatically different results  from other research.
“It’s a huge effect, and an effect that’s basically on the same order  of magnitude as the direct effect of climate change,” Elliott, a  research scientist with the Computation Institute’s Center for Robust  Decision Making on Climate and Energy Policy (RDCEP), Argonne National  Laboratory, is quoted as saying. “So the effect of limited irrigation  availability in some regions could end up doubling the effect of climate change.”
The “good” news, if any, is that some areas will most likely see more  precipitation, which could mitigate some of the effects of shortages,  the study says. Read on ...