Nothing is convenient to criticize like the food industry.   Environmental mullahs blame farmers for nitrogen and pesticides and greenhouse gases, though farming has actually "dematerialized" in the last 30 years and is producing the more food with only 60 percent of the land used in 1980.    Meanwhile, cultural fundamentalists decry the Utopian ideal every culture in history always sought to attain - cheap food.  So cheap people can eat a lot and choose to get fat.

But it's not a bilateral world any more, it is multilateral, and a third component has been introduced into the culture war; global warming.    A new study claims evil farmers would have made even more people fat except global warming has decreased food production.

Now, food production has not actually decreased in the last 30 years, it went up.  Way up.  But, properly framed, global warming can still be blamed if a projection is established where farmers would have produced even more without climate change.

What about the US, where temperatures have actually gone down?   Here's a sample of the odd rationalization that hurts the public's understanding of climate science:
For reasons still up for debate, temperatures largely held steady in the U.S. over the study period. So Iowa, by and large, doesn’t seem to have lost out. Rice and soybean yields have also proved resilient to rising temperatures so far, the team discovered.
I don't know what 'up for debate' means. To most people, when results are in defiance of the hypothesis, they are either outliers or the hypothesis is wrong.   30 years of outliers in the largest producer of CO2 seems a bit tough to accept.  The researchers behind the Science paper instead just say America has gotten lucky for the last three decades, which doesn't feel very scientific.   

David Lobell, assistant professor of environmental Earth system science at Stanford University and one of the authors behind the 'food has gone up but not as much as it could have' simulation (economists use those also - it is called a 'jobs saved' numerical model to prove someone did not get laid off if you redistributed wealth), says it makes sense to look into creating crops that can better withstand higher temperatures, in places where temperatures have actually gone up.

Oh wait, that introduces another group to hate farmers; the anti-genetic modification folks...

Citation: David B. Lobell, Wolfram Schlenker, and Justin Costa-Roberts, 'Climate Trends and Global Crop Production Since 1980', Science 5 May 2011: 1204531Published online 5 May 2011 DOI:10.1126/science.1204531