곡창지대와 물 먹는 하마

It's estimated that global crop production will have to double by 2050 to meet the demands of a world population that will by then be more than 9 billion. Worldwide, we've gotten pretty good at growing massive amounts of food, but there are a few limiting factors and points of inefficiency that are going to make it difficult to double up the world's collective food output. The major problem is water.

In too many parts of the world, the places producing most of the food are also places that require significant irrigation. This represents about 70 percent of global fresh water withdrawal, and produces about a third of the world's crops. Many of the places we're growing our food aren’t the places getting the rainfall needed to support such growth, which has caused us to find other ways of getting the water where we want or need it. But groundwater suppliesare diminishing.

That's made very clear in this global map, co-produced by ESRI and the University of Minnesota's Institute on the Environment, which shows where most of the world's food is being produced and where the most irrigation is required.

The U.S. offers a perfect example of what's holding us back. Food production is high throughout Central California, the Great Plains and throughout the Midwest.

But as this maps shows, major crop-producing areas like the Central Valley and the Great Plains are highly dependent on irrigation -- mainly from large-scale water projects and groundwater pumping.

This problem is even more apparent in places like India and Northeastern China.

We're not likely to stop growing food in these established breadbaskets. But given the growing demand for food, we'll need to start thinking about how to get more food growing in the places with natural abundances of water and how to make the areas we irrigate produce more with less water.

Maps courtesy: ESRI. Top image: Farmers irrigating crops in the Chinese province of Henan. Credit: David Gray / Reuters