A new study offers the most comprehensive assessment to date of how altering livestock grazing practices across the world’s rangelands could help reduce climate-changing greenhouse gas emissions.
Rangelands, which include grasslands such as prairies and savannas, cover about half of Earth’s surface. Generally poorly suited for crop farming, these lands host native vegetation that supports around 500 million people worldwide, feeding their herds of cattle, sheep, goats, and other animals.
Scientists and policymakers are seeking ways to improve how rangelands are grazed to address climate change by boosting plant growth and capturing more carbon dioxide, while maintaining livestock production. This strategy typically means preventing overgrazing, which damages root systems and causes erosion.
The new study, published June 11 in Science, reveals that reducing grazing and then supplementing animals’ diets with feed creates additional emissions that, in some regions, can undermine intended climate benefits. Researchers reached this conclusion by accounting for livestock feed supply chains, international trade networks, emissions from the livestock themselves, and land-use changes associated with growing feed crops such as corn, barley, oats, and soybeans.
“Our study adds important new context to estimates of how much carbon can be stored in soils through improved grazing practices in rangeland regions,” said lead study author Robert Powell, a PhD student at Cambridge University who is affiliated with the Fire Ecology Lab of Adam Pellegrini at Stanford. “In short, the picture is a lot more complicated in real life when you take a broader, systems-level view.”
Source : stanford.edu