Fighting climate change with grasslands
Grasslands have vast untapped potential to mitigate climate change by absorbing and storing CO2, according to a new report by FAO. Pastures and rangelands represent a carbon sink that could be greater than forests if properly managed.
Covering some 30 percent of the earth’s ice-free land surface and accounting for 70 percent of its agricultural land, the world’s 3.4 billion ha of grasslands can also play a major role in supporting the adaptation and reducing the vulnerability to climate change of over one billion people who depend on livestock for a living, according to the paper Review of Evidence on Drylands Pastoral Systems and Climate Change.
“The world will have to use all options to contain average global warming within 2 degrees Celsius. Agriculture and land use have the potential to help minimize net greenhouse gas emissions through specific practices, especially building soil and biomass carbon. These practices can at the same time increase the productivity and resilience of agriculture, thus contributing to food security and poverty reduction,” said FAO Assistant Director-General Alexander Müller.
Grazing lands are estimated to store 30 percent of the world’s soil carbon in addition to the substantial amount of above-ground carbon held in trees, bushes, shrubs and grasses. But they are particularly sensitive to land degradation, which affects some 70 percent of pastures as a result of overgrazing, salinization, acidification and other processes. Pressure on the land is also increasing in order to meet fast-growing demand for meat and dairy products.
Improved management practices restoring organic matter to grassland soils, reducing erosion and decreasing losses from burning and overgrazing can therefore help sequester large amounts of carbon – up to 1 billion tonnes a year according to some estimates. But this would require a vigorous and coordinated global effort and appropriate funding.
A more immediately feasible target would be to place 5-10 percent of global grazing lands under carbon sequestration management by 2020, which could store 184 million tonnes of carbon a year.
Socio-political and economic barriers need to be overcome too. They include land tenure, common property and privatization issues; competition from cropping; and lack of education and health services for mobile or nomadic pastoralists.
Increasing the amount of carbon sequestered in grasslands can help pastoralist populations adapt to climate change because the added carbon improves the soil’s water retention capacity and thus its ability to withstand drought.
Another consideration is safeguarding biodiversity. According to some estimates, the potential biodiversity of grasslands is only slightly less than that of forests. But there is also evidence that the number of animal and plant species and soil microorganisms resident in grazing lands is declining alarmingly through mismanagement, land use change and more recently climate change.
The report suggest that measures promoting improved grasslands management should include payment for environmental services (PES) which include both financial rewards and non-financial incentives such as capacity building and knowledge sharing. Increased access to existing development and funding mechanisms such as the Global Environment Facility should be made possible for efforts that contribute to sustainable use of grasslands and restoring their carbon storage potential.
Besides climate change mitigation, such efforts would also contribute to climate change adaptation and to the improved livelihoods of pastoral and agropastoral peoples.