Altering livestock grazing could allow soils to store billions more tonnes of carbon each year, depending on the region. However, net climate benefits depend heavily on the source of supplementary feed.
A new Cambridge-led 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 in the journal 'Science' on 11 June, reveals that reducing grazing and then supplementing animals’ diets with feed creates additional emissions that, in some regions, can undermine intended climate benefits. The 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 maize, barley, oats, and soya beans.
“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 author Robert Powell, a PhD student in the Ecosystem and Carbon Science group at the Department of Plant Sciences. “In short, the picture is a lot more complicated in real life when you take a broader, systems-level view.”
The study found that altering rangeland grazing could sequester an additional 2.2 billion tonnes of carbon dioxide equivalent per year, or about 4% of current annual human emissions. When accounting for emissions from feed production to maintain livestock, and from the animals themselves, the net climate benefits dropped by up to 31%.
The study’s region-specific findings can help agribusinesses and countries choose rangeland grazing practices that will cut emissions and move them closer to their climate goals.
“We’ve known that feed and supply chains are important sources of emissions from livestock production, but how they interact with potential mitigation of rangeland grazing has never been shown before,” said Dr Adam Pellegrini, the study’s senior author and former Head of the Ecosystem and Carbon Science group at Cambridge, now Assistant Professor of Earth System Science at Stanford University.
A data-rich approach
For the new study, the team gathered data from more than 200 previously published studies measuring how much carbon dioxide plants at 300 sites globally transfer into the soil through their roots, decaying leaves, and other detritus.
The researchers also compiled data on what livestock eat in different areas and how different feed mixes influence the animals’ digestion-related emissions of methane from burps and nitrous oxide released when bacteria break down faeces and urine. Animals that have their forage swapped out for feed tend to produce less of these potent greenhouse gases.
Additional data included the types of feed given to animals to supplement their diet when foraging is reduced to avoid damage from overgrazing, and the supply chains for the feed. The researchers also accounted for trade policies between nations importing and exporting feed, which influence transport-related emissions.
Sustainable solutions for rangeland and livestock
The researchers used this data to develop a full systems-level emissions model. The results suggest that land-use changes tied to feed production are a major factor in how effective grazing management can be as a climate solution. For example, Europe tends to import a lot of its animal feed from Brazil, where agricultural production can involve heavy deforestation that releases large amounts of carbon. Feed produced in the US Midwest is considered less carbon-intensive, partly because the region’s forests and natural prairies were converted to cropland long ago.
“The study shows why natural climate solutions in agricultural landscapes need to be assessed as interconnected food-production systems, not just as carbon sinks,” Powell said. “Improved grazing can have real mitigation potential, but its value depends on the broader system: livestock, feed, trade, and displaced production.”
Moving forward, the researchers said they hope the findings can inform the agricultural sector, policymakers, and other stakeholders looking to reduce emissions. “Natural climate solutions are very context-dependent, so you have to take local conditions into account when implementing, as we’ve seen here with rangeland grazing,” said Dr Pellegrini.
The team would like to expand the assessment framework further to include rapidly evolving data related to the impacts of climate change and geopolitical upheaval that affects fertiliser production and other agriculture-related variables.
“The framework we use in this paper could help make natural climate solution policy more realistic and useful beyond improved grazing alone. The next step is to better understand these mechanisms at finer regional and local scales, especially how plant productivity responds to different grazing changes under different environmental conditions,” said Powell.
“This study is giving us a picture of where we’re at now, not necessarily where we’re going to be in 5 or 10 years,” said Dr Pellegrini.
“It is a snapshot,” said Powell, “but our study highlights these critical issues for rangeland grazing optimisation, now and in the decades to come.”
“Looking ahead, we need to understand the links and trade-offs between different land-use strategies, rather than looking at each solution in isolation,” he said. “This means moving towards broader approaches that balance multiple goals, managing land use not just for the climate, but also for costs, biodiversity, livelihoods, and food production. This systems-level approach is vital to ensure that climate solutions in agriculture do not come at the expense of global biodiversity or food security.”
"This research provides a rigorous framework for estimating the actual climate impact of how we manage global rangelands," said co-author David Encarnation, a PhD student from the Department of Plant Sciences. "We are moving away from simplistic assessments that only look at soil carbon storage toward more holistic, systems-level approaches."
"Taking this broader view is crucial for accurately estimating the net climate benefit of interventions like reduced grazing, which can be significantly lower than previously thought. It also helps us identify the main drivers of emissions and how they vary across the globe."
Funding: This research was supported by the Natural Environment Research Council, United Kingdom Research and Innovation, and the European Research Council.
Reference: Robert S. Powell et al., ‘Assessing the net climate benefits of improved grazing intensity in global rangelands.’ Science (2026). DOI:10.1126/science.adz4320
Image: Cows grazing at Big Sur, California, USA. Credit: Manel Vinuesa / Getty Images.
Adapted with permission from an article by Stanford University published on 11 June 2026. Read the original article.