Friday, May 06, 2011

Climate Change Stunting World Grain Crops

Scientific American uses the term "Cereal Killer" to describe the impacts of climate change on efforts to increase production of cereal grains to feed the planet' s burgeoning population.

A recent study into already happening impacts of global warming found that it has cut "harvests of wheat 5.5 percent and maize 3.8 percent from what they could have been since 1980."

"On a global scale, we can see pretty clearly significant changes in the weather for most places where we grow crops ," explains agricultural scientist David Lobell of Stanford University's Woods Institute for the Environment, who led the analysis published in the May 6 issue of Science. "Those changes are big enough to sum up to pretty big losses for wheat and corn ."

U.N. Food and Agriculture Organization data going back to 1980 for crop yields in all major crop-growing regions of the world, and pairing that with temperature and precipitation data for their growing seasons, Lobell and his colleagues found that warming temperatures were reducing yields—although changes in precipitation did not appear to be having an effect, yet.

"Those temperature changes are the result of increasing
concentrations of atmospheric greenhouse gases, such as carbon dioxide (CO2), largely as a result of burning fossil fuels and agricultural practices. But CO2 also helps rice, soybeans and wheat grow. In fact, the researchers suggest the extra CO2 boosted yields for these crops by roughly 3 percent during the period studied ."

The study found that despite some CO2-driven crop increases, the temperature-caused decreases already outweigh them.   The researchers were also able to cost out the declines.   They found that climate change driven reductions had boosted the price of grain crops 18.9%.  They noted that companies like Monsanto are now busy developing plants that will be tolerant of higher temperatures.  Wait a second, isn't that Disaster Capitalism?   Isn't this the very sort of thing governments ought to be doing for the public good, not the private sector's?


Sixth Estate said...

I'm glad to see an accurate summary of this research. One of the Post's columnists yesterday claimed this paper's conclusion was that there had been no effect in North America and that the consequence of its publication would be greater recognition that we don't need to do anything about climate change.

I'm beginning to wonder whether the human species is intelligent enough to deserve survival.

The Mound of Sound said...

To answer your query - no. Every earth science type I know is utterly two-faced. They have an optimistic, "don't give up the ship" face they wear in public and a "we're screwed" face when we sit down over a couple of beers.

We're all Easter Islanders now.

BTW, the Post really did spin that study. In dealing with North America it found that the impacts haven't arrived here - yet. It also notes that our time will come, fairly soon.

sharonapple88 said...

Maybe it's already starting. Higher temperatures are connected with higher amounts of rainfall.

Wheat harvests were down 17% last year in Canada because of the flooding in the prairies.

The Mound of Sound said...

It certainly is starting, Sharon. The atmospheric warming has, as physics prescribes, increased water vapour saturation levels. This is more liquid water evaporated and taken from the surface. It is also a powerful greenhouse gas in its own right.

That extra atmospheric warm water vapour alters normal, pre-warming precipitation patterns. Some places get deluges instead of steady measured rainfall needed for agriculture. Others get drought. And that warm, moist air provides 'fuel' for severe weather events of increasing frequency and severity.