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

New Oxford Report: Carbon Capture and Storage Without Taxpayer Billions Is Possible
New Oxford Report: Carbon Capture and Storage Without Taxpayer Billions Is Possible

Oxford Net Zero and Carbon Balance researchers reveal the risks of the current UK CCS policy mix and explore how a carbon storage mandate on fossil fuel producers could help the UK meet its climate targets while protecting public finances A ... Read more

Oxford Net Zero partners with AXA XL on research in India, Mexico and Kenya
Oxford Net Zero partners with AXA XL on research in India, Mexico and Kenya

Oxford Net Zero is excited to announce that it is working with the insurance company AXA XL, the Institute for Science, Innovation and Society (InSIS), and the Smith School of Enterprise and the Environment to conduct research on private sector ... Read more

Finance, Fossil Fuels and $10 coffee: Reflections on COP29
Finance, Fossil Fuels and $10 coffee: Reflections on COP29

As we begin a new year, Oxford Net Zero looks back on the highs and lows of November's climate summit in Baku. In some ways, this COP was different. The venue was smaller than in previous years, which meant that attendees could have genuine ... Read more

See more news and events