Upward disruptions to agriculture and landscape threaten Paris climate agreement goals

One of President Joe Biden’s first acts after the inauguration was to realign the United States with the Paris climate agreement, but a new study by researchers at the University of California, Irvine, shows that increased emissions from human land use will jeopardize the objectives of the agreement. without substantial change in agricultural practices.

In an article published today in Nature, the team presented the most comprehensive inventory to date of land use contributions to carbon dioxide and other greenhouse gases (including nitrous oxide and methane) from 1961 to 2017 , taking into account emissions from agricultural production activities and changes to the natural landscape.

“We have estimated and assigned global emissions from land use in 229 countries and regions and 169 agricultural products,” said lead author Chaopeng Hong, UCI postdoctoral researcher in Earth System Science. “We looked at the processes responsible for higher or lower emissions and paid particular attention to net CO trends.₂ emitted by land use changes, such as the conversion of forested land to agricultural area. “

The researchers learned that the poorest countries in Latin America, Southeast Asia and sub-Saharan Africa experienced the most pronounced increase in these “land-use change” emissions.

East Asia, South Asia and the Middle East produced fewer greenhouse gases due to land-use change, the study found, but the regions’ agricultural emissions were rising sharply as production rushed to keep up with population expansion. And richer North America, Europe and Oceania showed negative land-use change emissions, but substantial pollution from agriculture nonetheless.

“While the situation in low-income countries is critical, the possibilities for mitigation in these regions are vast and clear,” said lead author Steve Davis, associate professor of earth system science at UCI. “Improving yields on land already cultivated can avoid clearing more carbon-dense forests for the cultivation of soybeans, rice, maize and palm oil, thereby significantly reducing emissions from use. land in these countries. “

The authors suggest that countries in emerging and developed markets can also reduce emissions intensity from agriculture by adopting more efficient plowing and harvesting methods, improving soil and livestock waste management, and reducing waste. food waste.

In addition, dietary changes could help, according to the study, which indicates that while red meat provides only about 1 percent of the calories produced in the world, it is responsible for nearly a quarter of all gas emissions. greenhouse effect linked to land use in the world.

Europe has the lowest emissions from land use, at 0.5 tonnes per person per year, the researchers note, but the figure is significantly higher almost everywhere else, and as the planet’s population continues to increase, farmers and policymakers will need to meet and exceed best practices.

The document highlights some promising technological solutions, such as new methods of rice cultivation that create less methane and feed supplements for cattle that reduce their harmful emissions by up to 95 percent.

“Feeding the planet can still generate significant greenhouse gas emissions,” said Davis, executive board member of UCI’s Solutions that Scale initiative, which seeks answers to the most pressing climate and environmental issues. of the planet. “Even if we reduce emissions to European levels around the world, with population growth expected, we could still envision more than 5 gigatonnes of emissions from land use per year in 2100, an amount at odds with the ambitious international climate targets, unless offset by negative results. emissions. “

The project – funded by the National Science Foundation, the German Research Foundation, and the Gordon and Betty Moore Foundation – also included researchers from the University of California at San Diego; Colorado State University; Stanford University; and the German Institute for Meteorology Max Planck.