The impact of global warming on food security

As extreme weather events increase around the world, the impacts of global warming on daily life are becoming more and more apparent. Rising temperatures are also having an impact on critical food crops, with 2021 estimates from Aalto University indicating that a third of global food production could be at risk.

Now, researchers from the university have developed a more precise model of where and how warming will affect our ability to grow food. Their findings have been published in Nature Food.

The study examined how future changes in temperature, precipitation and aridity will affect growing conditions of 30 major food crop species across the globe. An important finding was that low-latitude regions face significantly worse consequences than mid or high latitudes. Depending on the level of warming, up to half of the crop production in low-latitude areas would be at risk as climate conditions become unsuitable for production. These regions would also see a large drop in crop diversity.

“The loss of diversity means that the range of food crops available for cultivation could decrease significantly in certain areas. That would reduce food security and make it more difficult to get adequate calories and protein,” said Sara Heikonen, the doctoral researcher who led the study.

Up to half of the world’s food crops potentially affected

The study indicates that warming will severely decrease the amount of global cropland available for staple crops like rice, maize, wheat, potato and soybean, which account for over two-thirds of the world’s food energy intake. In addition, “tropical root crops such as yam, which are key to food security in low-income regions, as well as cereals and pulses, are particularly vulnerable. In sub-Saharan Africa, the region which would be impacted most, almost three-quarters of current production is at risk if global warming exceeds 3°C,” Heikonen said.

In contrast, mid- and high-latitude areas will probably retain their productive land overall, although zones for specific crops will change. These areas will also likely see an increase in crop diversity. “For example, the cultivation of temperate fruits, such as pears, could become more common in more northerly regions,” Heikonen said.

However, other factors could hamper agriculture in these areas, cautioned senior author Professor Matti Kummu.

“We showed that there’s climatic potential, but, for example, warming might bring new pests and extreme weather events, which our model doesn’t include. So the situation isn’t really that black and white,” he said.

Adjusting and adapting

Many of the low-latitude regions threatened most by warming are already vulnerable in numerous ways. They face problems with food sufficiency as well as economic and systemic forces which make them less resilient than northern countries. In spite of this, Kummu said there are ways to partially manage such challenges.

“In many low-latitude areas, especially in Africa, the yields are small compared to similar areas elsewhere in the world. They could get higher yields with access to fertilisers and irrigation as well as reducing food losses through the production and storage chain,” Kummu said.

“However, ongoing global warming will add a lot of uncertainty to these estimates and probably even more actions are needed, such as crop selection and novel breeding.

“But I always say that the modelling and analysis is the easy part –– understanding how to make the changes happen is the hardest part.”

While policymakers in low-latitude countries should work to close those gaps, in mid- and high-latitude regions farmers and policymakers need more flexibility, Kummu said. Warming will likely change which crops are grown in those areas, and further changes will come from the array of pressures on the global food system. Coping with those changes will require the ability to adjust and adapt as the consequences of climate change unfold.

“If we want to secure our food system in the future, we need to both mitigate climate change and adapt to its effects,” Heikonen said. “Even if the biggest changes are in equatorial regions, we will all feel the effects through the globalised food system. We need to act together to address these problems.”

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