Photograph by Bob Nichols/U.S. Department of Agriculture
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A field of dry cornstalks shows the affect of the drought in Texas in August 2013.
Photograph by Bob Nichols/U.S. Department of Agriculture

Changing Climate Will Create a Warmer, Hungrier World

Earlier this week, the Intergovernmental Panel on Climate Change—a multinational expert group chartered by the United Nations, known as the IPCC—issued its latest report, and its predictions for how changing climate will affect food production are dismaying.

The panel made its Synthesis Report available now because a new international treaty on climate will be attempted next year. (The report is here and a very short summary is here.) It is a “synthesis” report because it sums up several previous reports, but the language in this new one may be more stark than any of the publications that have come before. Among its warnings: The impact of warming is already being observed around the world. Levels of greenhouse gases in the atmosphere are higher than they have been at any time in 800,000 years. Burning fossil fuels without attempting to limit their carbon impact must end by 2050 or damage to climate will be irreversible.

But the IPCC’s most blunt statements may be reserved for the current impact—and unnerving future—that a warming climate and its weather effects have in store for food raised on land and harvested from the sea. Its observations, contained mostly in this section of the report, put together the effects of warming temperatures, changing amounts of rain, and increases in gases such as ozone. Here are some of its observations:

Yields of the most important edible grains—wheat and corn, and to a lesser degree rice and soybeans—have already been harmed by rising temperatures in most growing areas, offset only by some gains in higher latitudes such as far northern Europe and northern China.

Warmer ocean waters are forcing major fish species—already reduced from overfishing—away from the areas where fishing fleets operate and toward the poles. In the tropics, warmer waters are killing coral reefs, destroying fish habitats.

Higher temperatures and increased rainfall are also forcing down wild fish populations in lakes and rivers in Africa and India, and affecting the yields of aquaculture projects in those bodies of water too.

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Graphic courtesy U.S. Department of Agriculture via Creative Commons 2.0

The occurrence of diseases that harm livestock—such as bluetongue, a cattle virus—is rising. So are pests that affect land crops, while warmer temperatures provide friendlier conditions for dispersing weed seeds.

Those are the things that are already happening. Without curbs on greenhouse gas accumulation, the report warns, effects on food production will be more dramatic: Food and fodder crops will contain less protein, starch and minerals, making them less nutritious. Livestock will experience heat stress, reducing their growth and reproduction and the amount of meat and milk they produce. Flooding will destroy the near-shore fishing and aquaculture that are major food sources especially in South and Southeast Asia, and ocean acidification will harm seafood and shellfish in more temperate areas. Rising winter temperatures will reduce the yield of fruit and nut crops that require a period of cold as part of their growth cycle, and encourage the spread of plant diseases that now are curbed each year by winter temperatures.

It’s important to note that the worst effects of rising temperatures and their after-effects, such as extreme weather, flooding, and drought, are predicted to hit hardest in the tropics and subtropics. Those are also the poorest areas of the globe, and so they are most likely to be affected by a predictable follow-on to changes in food production: rising prices.

“Climate changes are expected to result in higher real prices for food past 2050,” the report observes. “Without accelerated investment in planned adaptations, climate change by 2050 would increase the number of undernourished children under the age of 5 by 20 to 25 million (or 17 to 22 percent).”

Embedded in the warnings about reduced food production is a concern about the social effects that would follow. If people cannot feed their families in a place where they formerly did, they are likely to leave it, contributing to refugee movements, overcrowding in cities, and social unrest that in the worst cases can be exploited by extremist groups. The report also underlines an issue that so far has gotten little attention in the debate over the extent of climate change: the degree to which food production supports local economies. If sugar cane or rice are no longer successful in the areas where they have historically been grown, then the webs of commerce that grew up around them—cane mills and sugar factories, rice processing and packaging plants, transport hubs—come apart as well. That leads to jobs being lost and income no longer going into local economies, which destabilizes societies while also forcing people to relocate for income as well as food.

A striking aspect of the report is how pessimistic it is, using terms like “high confidence” and “virtually certain” for many of the predicted effects. It assumes that the negative impacts—some of which can already be perceived—will occur much faster than any strategies can be put in place to mitigate them. For food production, that would include converting large areas historically devoted to one type of crop or livestock over to another or breeding and introducing crops more tolerant of heat and drought.

Climate change is a political hot-button, and given the results of the U.S. election this week, it’s difficult to imagine that the report and the forthcoming treaty negotiations will be welcome in Washington, D.C. But the tone of the officials releasing the report was not just determined, it was almost fatalistic. Ban Ki-moon, the U.N.’s Secretary General, said as the report was released:

“Science has spoken. There is no ambiguity in their message… Leaders must act. Time is not on our side.”

This story is part of National Geographic’s special eight-month Future of Food series.