“The world’s grasslands are an essential carbon sink, and may even be more efficient at capturing atmospheric carbon than trees. But thanks to animal agriculture and fertilizer use, they’re now producing as much greenhouse gas pollution as they sequester, according to a new study published in Nature Communications on Tuesday.
Grasslands themselves are exceptionally resilient to the climate crisis. As the world has warmed, for instance, wildfires have become more frequent and more severe; when these fires strike forests, trees release the carbon they’ve sequestered over their lives. But when prairie land burns, carbon tends to stay safely trapped in the soil. Previous studies have also found that grassland plants and soil have adapted to increased greenhouse gas pollution in the atmosphere by sequestering more carbon, methane, and nitrous oxide.
But around the world, grasslands are also being converted into pastures to raise livestock for meat, eggs and milk, which is a problem for the climate, since cattle digestion produces planet-warming methane, and cows’ excrement also releases nitrous oxide, another greenhouse gas. The introduction of nitrogen-based fertilizers to grasslands’ soils has also caused them to emit more nitrous oxide into the atmosphere. According to the Food and Agriculture Organization, animal agriculture is responsible for a whopping 14.5% of global greenhouse gas emissions. At the same time, breeding cows and other livestock degrades soil health and causes soil erosion—both of which inhibit the ground’s ability to store carbon.”