Agriculture has gotten a bad rap in recent years for its contributions to greenhouse gas emissions, perhaps for good reason. A 2014 Food and Agriculture Organization estimate showed that emissions from agriculture have more than doubled since 1961 and will continue to rise in the next few decades.

An international team of scientists has now calculated exactly how much farmers will have to cut emissions in order to limit global warming to 2°C in 2100. Non-carbon dioxide agricultural emissions—which are methane and nitrous oxide—will have to be cut by one billion tons every year by 2030, the team reported in a study published this week in the journal Global Change Biology.

Meeting those targets while ensuring that farmers, especially in the developing world, can keep producing enough food will require new high-impact technological solutions, as well as policies and major investment to scale them up, the researchers say.

Agriculture contributes about 5–5.8 gigatons of carbon dioxide equivalent a year, which is about 11 percent of manmade greenhouse gas emissions. The team used known assessment models to estimate that staying within the 2°C warming limit will require agricultural emissions reductions of 0.97–1.37 gigatons of carbon dioxide equivalent. But known practices such as intensified production of crops, better livestock management, efficient use of water, and nutrient management for annual crops will only reduce emissions by 21–40 percent.

At least 119 out of 195 countries have so far pledged to reduce agricultural emissions to meet the Paris climate summit goals. How can these nations further reduce emissions to meet their targets? Fortunately, there are several solutions in the pipeline.

Promising options include recently developed methane inhibitors that reduce dairy cows’ digestion-related emissions by a third while increasing body weight; cattle breeds that produce less methane; and wheat and corn varieties that inhibit the production of nitrous oxide. But we will still need coordinated international research efforts and investment to develop high-impact and easily implementable technical options.

Strong technical assistance for farmers, such as innovation hubs, technical support via mobile phones, and web-based information portals, will be crucial in fostering changes in behavior, the researchers say. Monitoring and improving these mechanisms based on feedback will also be key.

Developing countries produce the most agriculture-related emissions, and emissions are expected to rise the fastest there. So new technologies need to be affordable and accessible to farmers in these nations.

While the study focuses on non-carbon emissions, the researchers point to the need to slash CO 2 emissions as well. Potential ways to do this include sequestering carbon in soil, reducing land clearing for farming, and reducing food loss and waste.

The researchers point out that developing a global target is the first step to guide countries’ research agendas and farming policies to reduce agricultural emissions without compromising food security. According to Eva Wollenberg, of the University of Vermont’s Gund Institute for Ecological Economics and the paper’s corresponding author, “this research is a reality check.” —Prachi Patel | 19 May 2016

Source: E. Wollenberg et al. Reducing emissions from agriculture to meet the 2°C target. Global Change Biology 2016. DOI: 10.1111/gcb.13340.

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