There is a report out showing that global warming is already having some effect on crop yields. The main stream media that are reporting on it are not sounding too alarming; but it should be understood that global warming was supposed to be something that would effect us soon, not right now. One reason the effects have not been worse is that the crop growing regions of the United States have not been effected yet.
Hindering Harvests: Changes in the climate are already having an effect on crop yields—but not yet a very big one, The Economist, 5 May 2011.
Wheat yields are down 5.5% compared with what they would have been with no climate change, and maize yields are down 3.8%. For soya, some places saw improvements, some saw damage, with no real net effect on the global scale. For rice, warming brought a clear benefit for crops at higher latitudes and some losses in warmer places. Temperature played a bigger role than precipitation. The results seem to fit with previous studies into such effects in individual countries.
Some people will be surprised, even dismayed, that comparatively modest climate changes are already doing measurable damage. But in context, it is quite small. Yields have been going up around the world despite the warming climate—and over 29 years those increases swamp the estimated global reductions due to climate.
There is one quick fix:
Moreover, there is a simple way more or less to abolish the effect of climate change on yield to date. According to William Cline of the Peterson Institute for International Economics in Washington, DC, at least 4% of the world’s grain is used to make ethanol for fuel. Most of this is doing little good for the environment, and stopping subsidies for such fuels would boost the supply of grain for feeding people on a scale similar to the hit that the past three decades of warming have provided.
The BBC had a report as well.
Neither report comments on the fact that we need food supplies to drastically increase because we are supposed to be getting a world population pushing 10 billion people at some point and will have a lot of mouths to feed.