Last week we noted the astronomical increase in the human population since the beginning of the industrial revolution. The world population remained below 1 Billion people for several thousand years, but around 1820 began to increase. Today the world population stands at around 8 billion. Most of that increase has occurred since 1950.Why has this occurred, and how has this been possible?

 In part it is because of the increase in human productivity due to improved technology, but mostly it is due to the development of the technology necessary for the conversion of natural gas into nitrogen fertilizer. The chart below which graphs average corn yield in the USA tells the story. In the 1930s the industrial conversion of natural gas into nitrogenous fertilizer came into its own, and with that yields began going up in the industrialized world. Until this technological breakthrough, the barrier to increased crop yield had been plant available nitrogen in the soil. This barrier was now removed.

Of course it has not only been nitrogen. There has also been insect control, weed control, disease control, other fertilizers, genetics and tillage. The yield did not shoot up immediately in the 1930s. No, yields have gone up in a steady, impressive way as scientists and farmers working together, have continually found innovative ways of combining all this knowledge to achieve these yield increases. And the curve has not yet leveled off. Yields continue to increase.

 Initially these impressive yields were limited to the industrialized world, but it did not remain that way. Beginning in 1945, and gaining momentum in the 1950s, the “green revolution” transformed Mexico, India and the countries of Asia from countries of endemic famine to countries with food surpluses. This was achieved by developing high yielding varieties that responded to ideal fertility, irrigation and excellent weed and pest control. But it's taken us 70 years to get to where we are now.

 And that's where the problem is! The end of cheap oil and cheap natural gas is in sight. “No problem,” say those most confident of our human ability to innovate. “As soon as the price of fertilizer goes up, market forces will drive the development of equally productive varieties which don't need large amounts of added nitrogen fertilizer.”

 Maybe. But it took us 70 years to develop the nitrogen dependent varieties we now have. What reason do we have to believe we can,  within a reasonable time frame, develop varieties that don't need the fossil based fertilizers? And if we can't maintain our current yields, where will the food we need come from?

As a minimum response to the prospect of high natural gas prices leading to high fertilizer prices, governments need to ensure that at least as much research goes into the development of chemical free agriculture as is going into the development of chemical dependent agriculture. And we, each, can do our part to encourage low chemical agriculture by buying chemical free produce where we can.