The new research highlights the challenge of cultivating food on a warming planet.
Two recent studies – one history and the other forward tour – examine how the rise in temperatures has done and could continue to make agricultural production less effective, fundamentally remodeling the global food system while producers try to adapt to warmer growth seasons.
The results illuminate the link in which farmers and consumers are found. Agricultural production is a climate change engine; It is estimated that he is responsible for somewhere between a quarter and a third of global greenhouse gas emissions. But it is also hampered by changes under the weather conditions associated with climate change. While producers find it difficult to harvest the same quantities of food in the face of droughts, heat waves and hurricanes, buyers are more likely to deal with food prices.
The prospective study, published on June 18 in nature, analyzes the impact of warming temperatures on the caloric production of agricultural production. Researchers from the University of Illinois Urbana-Champaign and the Stanford Doerr School of Sustainability have revealed that for each additional degree Celsius of warming over the average 2000-2010, the global food system will produce approximately 120 calories per person per day.
In a scenario where the earth experiences 3 degrees Celsius of warming by the end of the century, it is the equivalent of everyone on the planet missing breakfast, said Andrew Hultgren, principal author of the study.
Hultgren and his colleagues have compiled a set of massive data on the production of six basic cultures in more than 12,000 regions distributed in more than 54 countries. They then modeled how different warming scenarios could have an impact on the production of cultures; They have also taken into account how farmers around the world are adapting to higher temperatures. What they found is that, even with adaptation, global warming is associated with an “almost linear drop in caloric production,” said Hultgren, who is also assistant professor of agricultural economy and consumption at the University of Illinois Urbana-Champaign.
The measurement of agricultural adaptation and its impact on production were significant, said Hultgren, because research often assumes that farmers adapt perfectly to global warming or not at all. The reality is that adaptation to all the challenges of the growth season comes at a cost, and farmers constantly weigh the trade benefits of the implementation of new techniques.
For example, a tool that producers of corn from the United States should prevent hot days from thwarting their harvest is to plant grape varieties that ripen relatively quickly. “Corn is very sensitive to extreme heat,” said Hultgren, “so a very hot day can actually be bad for all your growth in the growth season.”
But the rapid mass grape varieties also often produce lower yields overall, which means that these farmers can probably not sell as much corn as they have in cooler weather conditions, said Hultgren. “So there is literally a cost to avoid this extreme heat,” he said.
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A decrease in the global supply of crops will also increase in food prices. But Hultgren noted that the impacts of the reduction in agricultural production will not be distributed also. In richer countries such as the United States, for example, those which can afford the prices of higher foodstuffs probably eat the cost. In poor countries, these changes could worsen food insecurity.
In addition, the increase in temperatures will have an unequal impact on producers; The study estimated that in a climate scenario with high warm-up, corn producers in the United States will suffer losses of 40 to 50% yield by the end of the century. Based on these projections, “you are wondering if the corn belt continues to be the corn belt,” said Hultgren. Meanwhile, other regional producers – such as rice producers in South and Southeast Asia – will see the yields developing in the same time. “There are absolutely winners and regional losers in this world aggregate,” he said.
The historical study, published on June 20 in Nature Geosciences, examines one of the ways whose agricultural production contributes to global warming: the land clearing. When farmers want to cultivate new cultivated land, they often start by eliminating plants that are already growing there, whether grass, shrubs or trees. When the land clearing occurs in the rich carbon-rich regions of the world’s southern southern, such as the Amazon forest, it increases deforestation and carbon emissions, said Jessica Till, co-directed study author.
“Deforestation in tropical areas is one of the most urgent problems and the largest areas of concern,” said Till, a researcher at the University of Illinois Urbana-Champaign. (Till and Hultgren were not involved in the studies of the other.) “The more land you are, the more you remove the forest to create cultivated land, which will have a negative effect on the climate.”
Till and the other authors of the study examined this feedback loop between agriculture and the environment: when crop production becomes less effective due to weather conditions and extreme heat, farmers must acquire and erase more land to stimulate production. This expansion in cultivated land in turn leads to higher greenhouse gas emissions, which worsens warming and makes the production of crops even less effective.
They found that, even with improvements in agricultural productivity (due to technological improvements such as new varieties of seeds and an application of precision fertilizers), climate change was responsible for 88 million hectares, or 217 million acres, in the expansion of cultivated land in the world – an area almost twice the size of California – between 1992 and 2020.
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They also determined that this expansion was directed by large agricultural producers, including the United States, India, China, Russia and Brazil. Unsurprisingly, these countries were also the five best highest transmitters of greenhouse gas emissions resulting from climate expansions in cultivated land.
Tell and Hultgren noted that these changes can also influence world trade. When certain regions see a drop in agricultural productivity, said that Till, other regions will gain a competitive advantage in the international agricultural products market.
Erwan Monier, Codirector of the Climate Adaptation Research Center at the University of California Davis, said that he was not surprised by the results of the studies and said that they contributed to the entire research on climatic impacts on agriculture.
But he added that the two come with warnings. Monier noted that the study of nature on caloric production does not take into account possible future progress in technologies such as genetic edition which could make cultures much more resilient to climate change. He said that the document shows that “in order to really limit the impact of the climate on our ability to grow food, we will need an innovation and adaptation scale that is really substantial, and this will be a real challenge.”
Referring to the document of the nature of geosciences on the feedback loop between agriculture and the climate, Monier said that it did not take into account the way in which farmers’ behavior could change in response to global warming.
“The fact is that we have the ability to change what is developing where,” said Monier. In the United States, for example, where corn and soy production reign, farmers could choose to plant different crops if they see the yields drop in a coherent manner. These producers will not “continue to grow corn with very low yields and will invest more capital and land with very, very low yields,” said Monier. “Farmers will move away towards something that is actually more precious and develops well” – and that, in turn, could reduce the need to generate more land.
Monier recognized that this last study could appear to be quite pessimistic. But, he said, it underlines the importance of now having difficult conversations on how to cultivate enough food to feed the world population as temperatures climb.
In order to avoid serious losses in agricultural production, he said, researchers and climatic institutions must work hand in hand with farmers, helping them to understand the risks of global warming and to seek new ways of adapting. This work should be “from bottom to top,” said Monier, rather than “top down”. “We have to hire people who will grow food.”
He added that this will imply a work that extends beyond the academic sphere. “I do not know if the publication in the nature and geoscience of nature is the means of really leading the upward adaptation to the scale which is necessary.”
