Science - Study Posits 5% Global Drop In Wheat Yields In Past 30 Yrs. From Climate Disruption - BBC

Shifts in the climate over the past three decades have been linked to a 5.5% decline in global wheat production, a study has suggested. A team of US scientists assessed the impact of changes to rainfall and temperature on four major food crops: wheat, rice, corn and soybeans.

Climate trends in some countries were big enough to wipe out gains from other factors, such as technology, they said. The findings have been published in the online edition of the journal Science.

"We focused on those four crops because they make up the bulk of calories consumed today," said research leader David Lobell from Stanford University.

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"Across the board, you see crop yields going up over the past 30 years, but the question is how much is climate modified (and) what would have happened if the climate was not changing. In some countries, we see that climate has only affected things by a few percent. In other countries, we see that yields would have been rising twice as fast. On a global average, we see that wheat production would be about 5% higher if we had not seen the warming since 1980. We see about the same for maize or corn."

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http://www.bbc.co.uk/news/science-environment-13297004