The global context of agricultural methane emissions
This paper sets out how far different sources of methane (both agricultural and non-agricultural) can be reduced by 2050, via technical changes. It argues that since methane accounts for about 40% of the warming effect of all greenhouse gases in the short term (because of its high Global Warming Potential but short atmospheric lifetime), reducing methane emissions is therefore useful for mitigating climate change between now and 2050.
The diagram below shows methane emissions in the baseline scenario (left) and with the maximum technically feasible reduction (left). Most mitigation opportunities come from improvements to waste management and fossil fuel production.
Image: Figure 4, Höglund-Isaksson et al. Global anthropogenic CH4 emissions 1990–2050 in the Baseline scenario (left panel) and with Maximum technically feasible reduction (MFR) including effects of technological development (right panel).
The majority of agricultural mitigation opportunities are from rice cultivation (44%) followed by enteric fermentation (37%). Changes to rice production include keeping fields dry for longer, growing different hybrids or using soil amendments. Regarding livestock, the paper notes that mitigation options are mostly limited to larger farms (over 100 livestock units) because of the economies of scale available on these farms. These mitigation options include treatment of manure in a biogas digester, changes to animal feed and breeding for increased productivity.
The paper argues that methane reductions from technical changes alone are unlikely to be sufficient, since the remaining methane emissions by 2050 would be over half of the emissions permitted for that year (from all greenhouse gases) based on the Intergovernmental Panel on Climate Change’s scenarios for staying under 1.5°C of climate warming. Hence, institutional and behavioural changes are also likely to be necessary, e.g. improving smallholders’ access to credit markets or reducing milk and beef consumption.
Methane is the second most important greenhouse gas after carbon dioxide contributing to human-made global warming. Keeping to the Paris Agreement of staying well below two degrees warming will require a concerted effort to curb methane emissions in addition to necessary decarbonization of the energy systems. The fastest way to achieve emission reductions in the 2050 timeframe is likely through implementation of various technical options. The focus of this study is to explore the technical abatement and cost pathways for reducing global methane emissions, breaking reductions down to regional and sector levels using the most recent version of IIASA's Greenhouse gas and Air pollution Interactions and Synergies (GAINS) model. The diverse human activities that contribute to methane emissions make detailed information on potential global impacts of actions at the regional and sectoral levels particularly valuable for policy-makers. With a global annual inventory for 1990–2015 as starting point for projections, we produce a baseline emission scenario to 2050 against which future technical abatement potentials and costs are assessed at a country and sector/technology level. We find it technically feasible in year 2050 to remove 54 percent of global methane emissions below baseline, however, due to locked in capital in the short run, the cumulative removal potential over the period 2020–2050 is estimated at 38 percent below baseline. This leaves 7.7 Pg methane released globally between today and 2050 that will likely be difficult to remove through technical solutions. There are extensive technical opportunities at low costs to control emissions from waste and wastewater handling and from fossil fuel production and use. A considerably more limited technical abatement potential is found for agricultural emissions, in particular from extensive livestock rearing in developing countries. This calls for widespread implementation in the 2050 timeframe of institutional and behavioural options in addition to technical solutions.
Höglund-Isaksson, L., Gómez-Sanabria, A., Klimont, Z., Rafaj, P. and Schöpp, W., 2020. Technical potentials and costs for reducing global anthropogenic methane emissions in the 2050 timeframe–results from the GAINS model. Environmental Research Communications, 2(2).
Read the full paper here. See also the Foodsource building block Agricultural methane and its role as a greenhouse gas.
While some of the food system challenges facing humanity are local, in an interconnected world, adopting a global perspective is essential. Many environmental issues, such as climate change, need supranational commitments and action to be addressed effectively. Due to ever increasing global trade flows, prices of commodities are connected through space; a drought in Romania may thus increase the price of wheat in Zimbabwe.