An international team of researchers investigated how focusing on the short- or long-term warming effects of methane can affect climate mitigation policies and agricultural dietary transitions.
When the effectiveness of mitigation policies is measured against methane’s long-term behavior, how effective is the promotion of low-meat diets at reducing greenhouse gas emissions compared to carbon pricing? An international team of researchers investigated how focusing on the short- or long-term warming effects of methane can affect climate mitigation policies and agricultural dietary transitions.
Methane (CH4) has a shorter atmospheric life than the other major greenhouse gases (GHG), particularly carbon dioxide (CO2) (around 10 years). It has a significant warming effect in the short term, but it fades over time. Methane’s contribution to agricultural emissions and climate change may vary significantly depending on the time scale considered. This has significant implications for the design of agricultural mitigation policies for global climate change.
The study, which was recently published in the journal Nature Food, shows how different valuations of methane, reflecting either a short- or long-term focus, may affect the cost-effectiveness of mitigation policies and the benefits of low-meat diets.
The study emphasizes the importance of methane abatement options in slowing agriculture’s contribution to global warming. Given methane’s relatively short atmospheric lifetime, which not only delivers climate effects on a relatively short time horizon but also contributes to climate change, it is an interesting and necessary component in agricultural mitigation policy design.Stefan Frank
Traditionally, the climate impact of a specific sector is measured by its annual greenhouse gas emissions, which are typically calculated using the Global Warming Potential over a 100-year period metric? GWP100? which calculates the change in atmospheric energy balance caused by a specific type of GHG emission However, because GHG emissions are reported as CO2-equivalents (a very stable GHG), GWP100 may fail to capture how the relative impacts of various gases change over time.
Most assessments of the emission reductions required from the agricultural sector to meet climate targets appear to have overlooked the short-lived nature of methane emissions. The authors investigated how different methane valuations influence the ranking of mitigation policies in agriculture and, as a result, the sector’s contribution to global warming.
“The study emphasizes the importance of methane abatement options in slowing agriculture’s contribution to global warming. Given methane’s relatively short atmospheric lifetime, which not only delivers climate effects on a relatively short time horizon but also contributes to climate change, it is an interesting and necessary component in agricultural mitigation policy design” Stefan Frank, a researcher in the IIASA Integrated Biosphere Futures Research Group, explains study coauthor Stefan Frank.
The findings show that mitigation policies focusing on methane’s short-term impact result in greater emission reductions, and the authors emphasize that focusing specifically on the short-term effects of methane will result in greater emission reductions compared to policies that do not consider methane’s short-livedness. Such strict mitigation policies may even cause methane’s contribution to climate change to fall below current levels (since the warming effect of methane disappears). Reduced methane emissions have the same overall effect as CO2 uptake or carbon capture and storage technologies in this regard.
The authors also emphasize that the impact of low animal protein diets as a mitigation option is highly dependent on the context. Methane emission intensity is not reduced as much by technical measures if mitigation policies are based on metrics that reflect methane’s long-term behavior (resulting in a lower relative valuation). Then, low-meat diets emerge as a more effective option for lowering emissions. Reduced meat consumption and, as a result, production in developed economies could become an especially powerful mitigation mechanism if policies are relaxed.
“The methane specificities, which include a significant warming effect and associated mitigation potential in the short term, as well as the “climate neutrality” of a stable level of emissions in the long term, merit separate treatment in climate mitigation policies. This has also been recognized in the Global Methane Pledge, announced by the United States and the European Union and supported by more than 100 countries, which represents a commitment to reduce global methane emissions by at least 30% from 2020 levels “y 2030,” says coauthor Petr Havlik, who directs IIASA’s Integrated Biosphere Futures Research Group.
A combination of innovative production-side policy measures implemented globally and dietary changes implemented in countries with high calorie consumption per capita could achieve the most significant emission reduction levels, assisting in significantly reversing agriculture’s contribution to global warming.