Famine may be the biggest trial of our common humanity. MUCH has been said about how BHP Billiton's bid for Potash Corporation and Canadian fertilizer company Agrium's play for AWB fit in with the growing issue of food security and food shortages. The corporate activity is a storm warning of how food shortages and famine will reshape the world and corporate strategies.

The Economist notes that by 2050 world grain output will have to rise by half and meat production will need to double to meet demand at a time when growth in grain yields is flattening out, there is little extra farmland and renewable water is running short.

Similarly, rising food prices are a poke in the eye that the world needs to remind us of how fragile the food production chain has become. The drought and bushfires in Russia, combined with limits on grain exports, have resulted in a 70 per cent price spike in wheat futures, which has caused prices for soy and barley to go up by 10 per cent.

The world is running out of farmland. Advanced farming depends entirely on fossil fuels likely to become scarce, supplies of nutrients for farming have peaked and fresh water resources are finite. With global warming, up to half the planet faces regular drought by the end of the century. Storms and the kinds of floods that have devastated Pakistan are tipped to become more frequent and intense.

The looming food crisis calls for us to better manage water, land, nutrients and other inputs. Green cities that grow food will need to be established and the real costs of food to the environment and society might be passed on consumers.

If Cribb's warnings are correct, the prospect of famine, the third horseman of the Apocalypse, will be the biggest trial of our common humanity. BHP and AWB are footnotes to a much bigger story of how it will reshape business and society.