Climate change likely to magnify ag’s environmental difficulties

Today, the journal Science has published what is believed to be the most comprehensive scientific review ever undertaken into how climate change is likely to exacerbate the environmental impacts that agriculture already makes. The study catalogues the extent to which the long-term health of people and nature depends on the resilience and sustainability of food production systems in light of ongoing climate change.

“The paper highlights where agriculture’s negative environmental impacts could be further magnified as the climate crisis deepens, exacerbating greenhouse gas emissions, nutrient pollution, and habitat and soil loss,” said lead author Yi Yang, professor at Chongquing University, which worked alongside numerous international institutions, including The Nature Conservancy, on this research.

The review comes as world leaders grapple with the challenge of feeding a growing population against an increasingly unstable backdrop. It predicts that climate change is likely to compound difficulties in agriculture by shrinking harvests, reducing the effectiveness of synthetic inputs like fertilizers, and accelerating the damage caused by crop pests and soil erosion. 

One concern is that these declining yields and fertility loss could lead to increased clearing of land for food production, causing the loss of wildlife habitat and biodiversity, while also necessitating increased application of fertilizer and pesticides to maintain productivity, with knock-on effects for surrounding ecosystems. The research also suspects that environmental impacts would worsen, even as the sector pivots to respond to climate-driven demands: from rice paddies emitting increasing levels of greenhouse gas methane and degraded soils releasing higher levels of nitrous oxide, to land clearance, chemical runoff, and soil tillage also accelerating the release of carbon emissions.

“There is already ample reason to fight climate change, but this paper highlights an additional reason — that it makes it harder to achieve sustainable agriculture,” said Joe Fargione, TNC’s science director for North America and a co-author of the report. “To feed a growing world, we need to continue to increase agricultural yields, rather than cutting down remaining rainforests and plowing up remaining prairie to expand agriculture. But that means conserving soils, weathering droughts, and controlling pests — all of which will be harder in a warmer world with bigger storms, deeper droughts, and longer growing seasons for pests.”

David Tilman, Regents Professor and McKnight Presidential Chair in Ecology at the University of Minnesota, believes there is hope. He noted that approaches that promote soil health — such as cover crops, no-till, and crop diversification — can also increase the ability of agricultural soils to store carbon. Agroforestry can diversify farmer revenue, provide shade for livestock, and serve as windbreaks while also sequestering further carbon. More efficient fertilizer use reduces water pollution as well as emissions of nitrous oxide — a greenhouse gas 300 times as powerful as CO2.

“Fortunately, many of the practices that make agriculture more resilient can also help slow climate change,” Tilman said.

But he warned that the longer we wait to mainstream these practices — alongside reducing emissions from energy, transportation, construction and other economic sectors, which have a far greater climate effect than agriculture in the U.S. — the harder it will be to make agriculture sustainable.