The worst US drought in half a century is further evidence that we are in the midst of a global food crisis. In 2007-08, there were riots in more than 20 countries, as the cost of commodities surged. After a brief respite, prices of corn and soya have in recent months risen to all-time highs. I believe this is evidence that we cannot sustainably feed a world population forecast to reach 10bn by 2050. Are we cowboy capitalists, with our love of growth at any cost, about to ride full speed into disaster?

Food prices have risen for three main reasons. Demand for meat from the expanding middle class in developing countries (especially China) absorbed corn and soya – one pound of beef carcass requires 30 pounds of grain and one pound of pork requires 12 pounds of soya. Chinese soya demand, growing at 10 per cent a year, has transformed the agriculture of the western hemisphere, which now has more acreage with the crop than with wheat. Second, the global population has continued to increase at a rapid pace. Third, the weather has become more hostile to farming, with a substantial increase in severe droughts, floods and heatwaves.

The UN has estimated that the world will be able to increase food production by 60 per cent over the next four decades. Although there is no consensus number, the academic literature suggests at least a 70 per cent increase in food production will be required by 2050. Moreover, I believe that the UN forecast is highly unlikely to be met, given the long list of farming troubles.