Climate change will change the places where many crops are grown
TOM EISENHAUER remembers walking through Manitoba, a province in central Canada, over ten years ago. Around his car were fields of winter crops, such as wheat, peas and rapeseed (rapeseed). Dense staples like corn (maize) and soybeans, which were more profitable, were scarce. The view is very different now. Over 5,300 square kilometers have been planted with soybeans and around 1,500 with corn.
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Mr. Eisenhauer’s company, Bonnefield Financial, hopes to profit from how climate change is altering Canadian agriculture. The company buys fields and leases them to farmers, both in Manitoba and across the country. Chances are, a warmer climate will steadily increase the value of its assets, allowing farmers in places where it invests to grow more valuable crops than they have traditionally selected. It is far from the only company to make such bets. Climate change could make a cornucopia of once frigid and unproductive land. It could also do great harm to areas that feed millions of people.
The amount of space used to produce food has been increasing for centuries. Since 1700, the area of cultivated land and pasture has quintupled. Most of this growth took place before the mid-20th century. From the 1960s, the widespread adoption of chemical fertilizers, the development of more productive varieties of cereals and rice, as well as better access to irrigation, pesticides and machinery, enabled farmers to make better use of the fields they were already working. In recent decades, technologies such as genome editing and better data analysis have made it possible to further increase yields.
Rising global temperatures that began in the late 20th century slowed productivity increases, but did not stop them. A recent study by researchers at Cornell University calculates that, since 1971, climate change resulting from human activity has slowed the growth of agricultural productivity by about a fifth.
The “headwind” caused by climate change will only intensify, says Ariel Ortiz-Bobea, one of the study’s authors. Their research found that the sensitivity of agricultural productivity increases as temperatures rise. In other words, each additional fraction of a degree is more detrimental to food production than the previous one. This is particularly bad news for food producers in places, like the tropics, that are already hot. Another study predicts that for every degree of increase in global temperatures, average corn yields will drop 7.4 percent, wheat yields will drop 6 percent, and rice yields will drop 3.2 percent. These three cultures provide about two-thirds of all the calories that humans consume.
In the decades to come, there will be more mouths to feed. The Institute for Health Metrics and Evaluation, a U.S. research group, estimates that the world’s population will grow from around 7.8 billion to 9.7 billion by 2064 (after which it will decline). The growing middle classes in many developing countries demand a greater variety of foods, and more.
Hence the importance of the changes that global warming brings to agricultural areas. By expanding the tropics, this will change the precipitation patterns in the subtropics. By warming the poles particularly quickly, it also quickly opens up the lands of high latitudes. The regions of northern America and China are warming at least twice as fast as the world average. As Mr. Eisenhauer’s experience in Manitoba can attest, cultures are already shifting to the poles in response.
A study by researchers at Colorado State University, published in Nature in 2020, saw notable changes in the distribution of several rainfed crops over the 40 years between 1973 and 2012, as farmers began to make different decisions about which crops were worth planting where. Corn production, for example, has spread from Southeastern America to its upper Midwest. Wheat has moved so north, with the help of new irrigation methods, that it has overtaken the warming trend: the hottest places where it is grown today are cooler than the places where it is grown. the hottest he grew in 1975.
Soybeans make up 65% of all protein supplied to farm animals. The cultivation of these magic beans has moved north and south as new breeds and other advancements have allowed it to thrive in the tropics. Rice harvesting areas in China have expanded northward since 1949. Wine grapes and fruit crops have also migrated north.
Mr. Eisenhauer says investors are increasingly looking for Canadian lands as a hedge against the climate risks they face elsewhere. Martin Davies of Westchester, a large agricultural investment firm, says he’s seeing similar trends in many parts of the world.
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The bravest investors spy on opportunities on land that currently supports no agriculture at all. At the moment, only about a third of the world’s boreal regions – a biome characterized by coniferous forests that cover large tracts of land south of the Arctic Circle – enjoy temperatures warm enough to grow the hardiest grains, such as oats and barley. This could reach three quarters by 2099, according to a study published in 2018 in Scientific reports, a newspaper (see map). The share of boreal land that can support agriculture could increase from 8% to 41% in Sweden. It could drop from 51% to 83% in Finland.
Efforts to cultivate these areas will alarm people who value boreal forests for their own good. And cutting down such forests and plowing the soils underneath will release carbon. But the climatic effects are not as simple as they seem. Northern forests absorb more heat from the sun than open farmland, because snow-covered farmland reflects light back into space (in forests, snow is under trees and not so directly illuminated). The fact that logging boreal forests does not worsen climate change, however, says nothing about the degree to which it could affect biodiversity, ecosystem services, or the lives of forest dwellers, especially indigenous people.
Some governments are already keen to take advantage of climate change. Russia has long spoken of higher temperatures as a godsend. President Vladimir Putin once boasted that they would allow Russians to spend less money on fur coats and grow more grain. In 2020, a “national action plan” on climate change outlined ways the country could “use the benefits” of climate change, including expanding agriculture. Since 2015, Russia has become the world’s largest producer of wheat, mainly due to higher temperatures.
The Russian government has started leasing thousands of square kilometers of land in the country’s Far East from Chinese, South Korean and Japanese investors. Much of the land, which was once unproductive, is now used for growing soybeans. Most are imported by China, helping the country reduce its dependence on imports from America. Sergey Levin, Russian Deputy Minister of Agriculture, predicted that soybean exports from his Far Eastern farmlands could reach $ 600 million by 2024. That would be nearly five times what they were. in 2017. The government of Newfoundland and Labrador, a province on the northeastern tip of Canada, is also trying to encourage the expansion of agriculture on forested land.
There is a way, in addition to the higher temperatures, by which the changes humanity is making to the atmosphere could help such projects move forward. Carbon dioxide is not just a greenhouse gas; it is also the raw material of photosynthesis thanks to which plants grow and eat. For most plants, all other things being equal, more carbon dioxide means more growth. The build-up of carbon dioxide over the past century has led to clearly measurable “global greening”, as the plants that benefit most from the higher levels of carbon dioxide thrive. This effect can help increase crop yields. But it is not an unalloyed good. Larger crops may not be more nutritious crops.
In addition, climate change will alter precipitation patterns. This will not necessarily benefit plans for more agriculture in northern climates. Many areas that become soft enough to be cultivated can end up running out of water, at least without intensive irrigation. Others may have too much. Crops are not the only organisms whose range expands as temperatures rise: pests and pathogens, which are often killed by cold winters, are also spread. Soil matters too. The best quality products are most often found at lower latitudes, and not at more northern latitudes.
Some emerging agricultural lands are close to established farming systems. But transforming remote areas of Siberia, to take an example, where many existing infrastructure is already collapsing and disintegrating due to melting permafrost, will be slow and costly. Border farms will also need to attract and accommodate many more workers. They will have to rely more and more on foreign migrants, an idea that voters in many wealthy countries do not like very much.
All in all, the expansion of farmland northward will only mitigate to some extent the damage climate change can cause to agriculture. The companies that will benefit are for the most part already rich. Poor regions, which depend much more on income from agricultural exports, will suffer.
A much wider range of adaptations will be needed to keep food as plentiful, varied and affordable as it is today. These will include efforts to help crops withstand warmer temperatures, for example through smart crop selection, advancements in irrigation and weather protection. Both rich and poor countries should also make it a priority to reduce the amount of wasted food (the UNThe Food and Agriculture Organization of the United Nations estimates that more than a third is wasted). The alternative will be a hungrier and more unequal world than it currently is – and could have been. ■
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This article appeared in the International section of the print edition under the title “New Frontiers in Agriculture”