Agroforestry is crucial to the food production challenge

The UN’s Intergovernmental Panel on Climate Change has just published the world’s most comprehensive study in seven years of the impact climate change has (and will have) on the world’s natural environment. Diversified farming, including agroforestry, may help mitigate the effects and food production, writes Patrick Worms.

Patrick Worms is the Brussels-based Science Policy Adviser of the Nairobi-based World Agroforestry Centre.

For the first time, the IPCC has found that climate change has “already affected agriculture, human health, ecosystems on land and in the oceans, water supplies, and some people’s livelihoods,”

Perhaps most worrisome is its finding that maize and wheat, the world’s most important food groups, are increasingly affected: “Periods of rapid food (…) price increases following climate extremes (…) indicate a sensitivity of current markets to climate extremes,” says its summary report. The threat of falling yields and rising prices is looming.

This is not surprising. Crop plants, like humans, have preferred temperature and humidity ranges at which they thrive. The productivity of maize, by far the world’s most important crop, falls off a cliff when it is exposed to temperatures above 38°C.  And such temperatures are already becoming more common across the globe, as droughts and heat waves become more frequent.

The bad news seemingly keeps on piling up. And yet Professor Chris Field, co-chair of the working group that produced the report, spoke of “exciting opportunities” in Yokohama last Sunday. That may seem surprising. But “understanding those challenges and tackling them creatively can make climate-change adaptation an important way to help build a more vibrant world in the near-term and beyond,” he said. Agriculture offers a key example.

Back in the 1960s, the world was also facing a food crisis. India and other countries, it was feared, would soon fall victim to giant famines thanks to runaway population growth. Hundreds of millions would die. And yet none of this ever came to pass. The Green Revolution package - hybrid seeds, chemical fertilizers, irrigation and phytosanitation - boosted farm productivity to levels previously unseen.

That revolution was based on the science of its time. Farming was optimised to produce a few crops cosseted in vast numbers on large, monotonous fields. This model still feeds the world, but is showing its limits. Chemical fertilizers are made with natural gas, a fossil fuel; tractors and irrigation pumps run on diesel. Both generate greenhouse gases. Aquifers are over-exploited. Soil microorganisms suffer from the intensive use of weedkillers and pesticides. And vast fields of single crops are uniquely exposed to extreme weather: there is nothing to protect crops from strong winds, hard rains, droughts or heatwaves.

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