Thursday, November 14, 2013
Limits to Agriculture in the 21st Century
Two key twentieth-century inventions have made it possible to feed the current human population on this planet. The first, which Alan Weisman (Countdown) calls the most important invention in the modern era, is the Haber-Bosch process (1909), which has enabled modern farmers to fix atmospheric nitrogen, vastly increasing the amount of nitrogen available to plant growth from what Nature has bequeathed us through the use of legumes. The second is Norman Borlaug's research (Nobel Peace Prize, 1970) leading to a dwarf disease and mildew-resistant strain of wheat, ushering in the Green Revolution, which has enabled poor Third World farmers to vastly increase their yields. India has gone from being a big importer of food in the 1960's to a net exporter now, thanks to the new strains of wheat. These two developments have extended our numbers from 1.75 billion in 1910 to 7 billion today.
It would be truer to say that these processes temporarily enabled farmers to maximize fertility without recycling the urine and feces of the animals and people that consume their crops, and controlling soil-depleting runoff, the way that nature does. The urine and feces, which contain the nitrate, phosphate, potassium, and other nutrients, are instead “thrown away” into sewers and streams, to eventually wind up in the ocean where they cannot be effectively recovered.
Nowadays, we compound the problem by mixing our human and animal wastes with toxics from our industries and households, thus guaranteeing their uselessness to agriculture.
Farmers’ reliance on commercial nitrates adds seriously to the rate of CO2 build-up in the atmosphere. But a very-probably-more-serious near-term threat to the world’s artificial-fertilizer-dependent agriculture is the phosphate issue. The mining industry has said there is still enough phosphate in the ground for humans to go on extracting it for centuries to come. It is in their commercial interest to say so: the equivalent of global warming denial by the petrochemical industry. But many scientists have been saying for decades that the readily-minable phosphate, like the easily-extractable petroleum, is fast running out.
I spoke about this to Friends back in the late 1980s, but there is more up-to-date data available now.
U.S. domestic phosphate production is expected to peak just twenty years from now, after which the U.S. will be as much at the mercy of phosphate exporters, mainly China, just as it is presently at the mercy of petroleum exporters.
Cordell, Drangert and White, writing in the May 2009 issue of Global Environmental Change, predicted that global “peak phosphorus” would arrive around 2040 AD. Jeremy Grantham, a business investment strategist who has compiled a very nice track record, especially in the prediction of economic crises and crashes (he can be Googled) takes the Cordell et al. forecast seriously and worked with Business Insider to create a pictorial presentation for dummies which you can look at and share as you feel moved.
Natasha Gilbert, reporting on the topic in the November 9, 2009 online issue of Nature, consulted with a wider range of scientists and gave a wider range of predictions. What she has is important because it underscores how little we know for certain.
If the Cordell et al. forecast is right, then forecasts about how humans will be affected by greenhouse warming after about 2035 are rather beside the point, because by then we will probably be using chemical, biological, and thermonuclear weapons on each other in real-life hunger games. We may fervently hope Cordell et al. are wrong!
But either way, it is clear that there is much more involved in the future of agriculture than nitrates, hybrid seeds, and accelerating climate change, and that the transgression of boundaries is a far more serious issue than Lynas imagines.
Soil erosion, topsoil carbon and mineral depletion, and soil structure destruction are big parts of the overall agricultural picture, too, but that would require a much longer discussion, and I don’t know that I can manage one right now.
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