Climate change, food supply and the role of genetically modified crops

I think higher food prices--the kind the poor will see much more than anyone reading this blog post--are one of the biggest risks from global warming.   If you don't care about whether the poor eat or not, I think you will care about the civil conflict that would accompany their hunger.  If GMOs solve the problem, great.  But I'm kinda skeptical that they will...
Here I am live at the New York Times Room for Debate:

About 30 years ago Julian Simon, an economist, made a famous bet with Paul Ehrlich, the entomology professor and author of “The Population Bomb.” The bet was about the future direction of resource prices.

Where Mr. Ehrlich saw population growth leading to scarcity in resources and higher prices, Mr. Simon saw an impending resource boom that would easily compensate for population growth. Mr. Simon handily won the bet.

Staple commodity prices — from food to oil to metals — have all trended flat or downward over the long run. Technological optimists point to this fact and believe resource scarcity is of little concern to our post-industrial society. In a sense, they’re right. But what about the part of the world that isn’t industrialized?

I am mindful of arguments coming from technological optimists who believe crop yields will continue to rise, that there is plenty of oil still left to find and that geo-engineering will solve global warming.

But I don’t think today’s doomsayers are a few voices in small corners of the scientific community. There is a real threat to worldwide food security over the next 10 to 40 years. The threat comes from global income inequality combined with projected global warming, which could cause tremendous declines in crop yields.

For the United States — by far the world’s largest producer and exporter of food commodities — my own statistical research with Wolfram Schlenker predicts yield declines of 18 percent to 35 percent for corn and soybeans due to global warming, and more than twice these losses by the end of this century.

A recent, far more comprehensive study by the International Food Policy Research Institute predicts large food production declines and higher prices for the whole world.

For people in the United States these dramatic predictions are actually of little direct concern. Raw commodities make up such a tiny share of retail food prices we would hardly notice a 10-fold increase in corn prices. The price of a quarter-pound hamburger (produced from corn-fed beef) would probably go up by less than a dollar. It’s hard to believe we’d buy much less meat as a result. Indeed, demand growth today comes less from population growth and more from rising incomes and meat consumption in China. (Keep in mind that it takes five to 10 calories of staple grains to make one calorie of meat.)

But three billion people — nearly half the planet — live on $2.50 per day or less. The poor typically spend a third to half of their income on food, composed mainly of staple commodities. If food quantities go down and prices go up, it’s the world’s poor who consume less.

If incomes were more equal around the world, prices would rise much further and we would buy less meat, but there would be little risk of famine.

Still, it could be that new genetically modified seeds will accelerate yield growth and offset projected damages from global warming. So far, genetically modified crops have shown yield gains in developing nations, but only modest gains in rich countries. And though yields have grown, my research shows no growth in tolerance to extreme heat, which is the key challenge going forward.

The green revolution didn’t come about from a wondrous market. It came from public investments in crop science that people like Norman Borlaug then spread around the world. But public funding of crop science research has diminished over the years. Now seems like a good time to increase that kind of investment.

 Update: I put a few further policy recommendations here.