Striking farming and landscape disruptions threaten the goals of the Paris climate agreement

One of President Joe Biden’s first actions after the inauguration was to bring the United States back into line with the Paris climate agreement, but a new study led by researchers at the University of California, Irvine, shows that increasing emissions of human land use will jeopardize the objectives of the agreement. without material changes in agricultural practices.

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

“We have estimated and attributed global land use emissions among 229 countries and territories and 169 agricultural products,” said lead author Chaopeng Hong, UCI postdoctoral scientist in Earth Systems Science. “We investigated the processes responsible for higher or lower emissions and paid particular attention to trends in net CO₂ radiated by changes in land use, such as converting wooded land into farmland. ‘

The researchers learned that poorer countries in Latin America, Southeast Asia and sub-Saharan Africa experienced the strongest increase in this “change in land use”.

According to the study, East Asia, South Asia and the Middle East produced fewer greenhouse gases due to land use change, but the region’s agricultural emissions grew strongly as production accelerated to keep pace with population expansion. And more prosperous North America, Europe and Oceania have shown negative emissions from land use changes, yet pollution by farmers.

“While the situation in low-income countries is critical, the mitigation opportunities in these places are large and clear,” said senior author Steve Davis, UCI associate professor of Earth Systems Science. “Improving yields on already cultivated land can avoid clearing more carbon-dense forests for the cultivation of soybeans, rice, maize and palm oil, thus drastically reducing land use emissions in these countries.”

The authors suggest that countries in emerging and developed markets can also reduce the emission intensity of agriculture by using more efficient tillage and harvesting methods, by better soil and livestock waste management and by reducing food waste.

In addition, nutritional changes may help, according to the study, which says that although red meat produces only about 1 percent of the world’s calories produced, it accounts for up to a quarter of the world’s greenhouse gas emissions.

Europe has the lowest land use emissions, 0.5 tons per person per year, say the researchers, but the figure is significantly higher almost everywhere else, and as the planet’s population continues to increase, farmers and policymakers will have to comply with the current best practices.

The article highlights some promising technological solutions, such as new ways to grow rice that create less methane and nutritional supplements for cattle that reduce their harmful emissions to 95 percent.

“The feeding of the planet can always yield significant greenhouse gas emissions,” said Davis, a member of the executive board of UCI’s Solutions that Scale initiative, who wants to find answers to the world’s most pressing climate and environmental problems. “Even if we reduce global emissions at European levels, with the expected population growth, we can still look at more than 5 gigatons of land use emissions per year in 2100, an amount that is contrary to ambitious international climate targets, unless it becomes negative 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, San Diego; Colorado State University; Stanford University; and Germany’s Max Planck Institute for Meteorology.