Climate warming from managed grasslands cancels the cooling effect of carbon sinks in sparsely grazed and natural grasslands

Aug 1, 2023

Grasslands absorb and release carbon dioxide (CO2), emit methane (CH4) from grazing livestock, and emit nitrous oxide (N2O) from soils. Little is known about how the fluxes of these three greenhouse gases, from managed and natural grasslands worldwide, have contributed to past climate change, or the roles of managed pastures versus natural grasslands. Here, global trends and regional patterns of the full greenhouse gas balance of grasslands are estimated for the period 1750 to 2012. A new spatially explicit land surface model is applied, to separate the direct effects of human activities from land management and the indirect effects from climate change, increasing CO2 and regional changes in nitrogen deposition. Direct human management activities are simulated to have caused grasslands to switch from a sink to a source of greenhouse gas, because of increased livestock numbers and accelerated conversion of natural lands to pasture. However, climate change drivers contributed a net carbon sink in soil organic matter, mainly from the increased productivity of grasslands due to increased CO2 and nitrogen deposition. The net radiative forcing of all grasslands is currently close to neutral, but has been increasing since the 1960s. Here, we show that the net global climate warming caused by managed grassland cancels the net climate cooling from carbon sinks in sparsely grazed and natural grasslands. In the face of future climate change and increased demand for livestock products, these findings highlight the need to use sustainable management to preserve and enhance soil carbon storage in grasslands and to reduce greenhouse gas emissions from managed grasslands.

Publication details
Theme(s)
Carbon dioxide removal
Type(s)
Research paper
Author(s)
Obersteiner, Michael
Year(s)
2021
Nature Communications

Latest news

Onshore geological carbon storage has potential in the UK, but key knowledge and regulatory gaps remain – ONZ report
Onshore geological carbon storage has potential in the UK, but key knowledge and regulatory gaps remain – ONZ report

A new report by a team of Oxford Net Zero researchers reviews the current state of knowledge on onshore geological carbon storage (GCS) and its feasibility in the UK. Read more

Oxford launches revised Offsetting Principles
Oxford launches revised Offsetting Principles

As part of their net zero strategies, many companies, organisations, cities, regions and financial institutions are relying on voluntary carbon credits to offset their residual emissions. But evidence continues to cast doubt on the integrity of ... Read more

Job Opening at ONZ: Impact and Operations Officer
Job Opening at ONZ: Impact and Operations Officer

Oxford Net Zero is looking for a highly organised and motivated Impact and Operations Officer to join its team. You will be working alongside the Programme Manager, Cath Ibbotson, and the Head of Policy and Partnerships, Kaya Axelsson to ... Read more

See more news and events