For the first time, scientists have calculated the reduction in emissions required in agriculture to reach the goal of the Paris Agreement to limit global warming to 2°C by 2100. CGIAR1 experts at the University of Vermont (United States) and partner institutions, including INRA, show that the world’s farming industries must reduce CO2 emissions by one gigaton per year between now and 2030. Between 21% and 40% of this goal could be achieved by using currently available methods to reduce methane and nitrous oxide emissions. Increasing the amount of organic matter in soils (carbon storage) is therefore essential. This goal is reflected in the "4 per 1000 initiative: Soils for Food Security and Climate’, launched at the COP 21 and governance of which will be adopted at the COP 22 in Marrakech (Morocco). The findings of this study appear in Global Change Biology.
Experts with the CGIAR1 Research Programme on Climate Change, Agriculture and Food Security (CCAFS) at the University of Vermont, and partner institutions including INRA, estimate that the farming sector must cut back emissions other than CO22 by one gigaton of carbon dioxide equivalent (CO2e) per year by 2030. However extensive analysis also revealed a significant gap between existing reduction options in this sector and required levels: current efforts would only reduce emissions by 21% to 40% of the required amount.
Scientists warn that emissions reductions in other industries like energy and transportation will not be enough to meet the obligations of the Paris Agreement on climate change. In their view, agriculture must also play a role and international organisations focused on agriculture and food security should establish a sector-specific goal of limiting global temperature increases to 2°C so as to direct efforts to more stringent reduction goals and to follow progress on goals.
119 countries have included agriculture-specific reductions among national-level commitments submitted to the United Nations Framework Convention on Climate Change (UNFCCC). However few specifics have been provided as to how these commitments will be fulfilled.
Currently, agriculture (with the exception of land-use change) is responsible, on average, for 35% of greenhouse gas emissions in developing countries and 12% of these emissions in developed countries. The authors do, however, warn that efforts to reduce emission levels must be compatible with the need to ensure sufficient food production, particularly in the world’s poorest countries.
Between 21 and 41% of the one gigaton (CO2e ) per-year reduction in gases other than CO2 in farming could be achieved using known methods, including:
‘ Sustainable intensification of livestock production;
- Efficient use of water through alternate wetting and drying techniques for irrigated rice;
- Nutrient management for annual crops, including the efficient use of nitrogen and manure;
‘ Relocalisation of production for a more effective use of inputs.
Undertaking this task would involve an enormous amount of investment, information sharing and technical support to ensure a smooth transition at the international level. But, according to the study, even such efforts will not suffice. Technology and policies with far greater impact will be necessary. Promising technical innovation is on the horizon, including methane inhibitors capable of reducing emissions emitted by cattle by 30% without altering milk yields, cattle breeds which produce less methane, and grain varieties which emit less nitrogen oxide.
Examples of policies supporting more ambitious reduction goals include: a more rigorous system of subsidies, pricing and carbon taxes; the adoption by governments and the private sector of sustainability standards which include emissions reductions in agriculture; and the improvement of farmers’ access to technical assistance in the use of locally-adapted reduction methods, via information portals which can be accessed on smart phones and the web, for example.
According to the authors, a greater focus on carbon sequestration in soils, more agroforestry, less food loss and waste and a shift in eating habits are other factors which could contribute significantly to reducing emissions from agriculture. However, far less research has been conducted on reducing emissions from these sources. Action is therefore needed now to identify options and their effects.
1 The Consultative Group on International Agricultural Research (CGIAR) is an international organisation tasked with the mission of coordinating international agricultural research programmes to reduce poverty and ensure food security in developing countries.
2 The study focused on emissions other than carbon dioxide (CO2) in agriculture, including methane (CH4) and nitrous oxide (N2O), both of which are greenhouse gases with a far worse impact on global warming than CO2. Soil carbon was excluded from the analysis because data is highly variable and relies on a considerable degree of speculation regarding what organic matter contributes, how carbon and nitrogen interact, apparent depth and density and saturation over time. Biomass carbon was also excluded due to a relative shortage in international data.
Wollenberg E. et al. Reducing emissions from agriculture to meet the 2°C target. Global Change Biology. 10.1111/gcb.13340 , 17 May 2016.