Cutting overlooked methane emissions central for limiting global warming

Evidence indicates that methane emissions were responsible for about half of global warming between the preindustrial period and the 2010s—but compared to carbon dioxide, methane has received comparatively little attention.

“The world has been rightly focused on carbon dioxide, which is the largest driver of climate change to date,” said study lead author Drew Shindell of Duke University. “Methane seemed like something we could leave for later, but the world has warmed very rapidly over the past couple of decades, while we’ve failed to reduce our CO₂ emissions. So that leaves us more desperate for ways to reduce the rate of warming rapidly, which methane can do.”

Reduce, coordinate, and incentivize

Methane is the second most potent greenhouse gas, but only about 2% of global climate finance goes towards cutting methane emissions. These emissions are also rising fast, due to a combination of emissions from fossil fuel production and increased emissions from wetlands, driven by the climate crisis. To slow the damage from climate change and make it possible to keep global warming below 2°C, we need to act immediately, following the Global Methane Pledge to reduce methane emissions by 30% from their 2020 level by 2030.

The scientists laid out three critical imperatives for action, backed by analyses of satellite remote sensing data, reported methane emissions, and the interaction of abatement options with market forces. Lena Höglund-Isaksson, a senior researcher in the Pollution Management Research Group of the IIASA Energy, Climate, and Environment Program, contributed data and ideas to the study and also conceived parts of the policy analysis, for example, about how investor perspectives and market distortions must be considered when designing effective policy instruments to target methane emission reductions, in particular in the fossil fuel production sector. The global methane module of the IIASA Greenhouse Gas and Air Pollution Interactions and Synergies (GAINS) model is one of three bottom-up models used in the study to assess the future mitigation potentials at a sector and region level.

Firstly, the authors found that we need to bring methane emissions down. Secondly, we need to coordinate efforts to tackle methane and carbon dioxide emissions—only cutting carbon dioxide won’t stop warming quickly enough, but only cutting methane just delays global heating. Thirdly, we need to incentivize and enforce methane abatement.

According to the authors, this is a life-saving, cost-effective measure. Estimates indicate that every tonne of methane emitted in 2020 caused US$470-1700 of damages. But this may be a significant underestimate: taking into consideration the effect on air pollution that damages human health, the findings indicate that the true cost could be up to $7,000 per tonne—and rising.

“The benefits of methane mitigation nearly always outweigh the net costs,” explained Shindell. “Many methane mitigation options provide net economic gains even without accounting for environmental impacts.”

ethane doesn’t accumulate in the atmosphere in the long term, which means that emissions reductions take effect more quickly. If we could cut all methane emissions tomorrow, in 30 years more than 90% of accumulated methane—but only around 25% of carbon dioxide—would have left the atmosphere.

“The most important mitigations are the available mitigation options across all sectors that aren’t too expensive, because we really need to do everything to reach climate targets such as 1.5°C or 2°C warming,” said Shindell. “Controlling methane from only one sector wouldn’t be enough. We need a broad portfolio of actions.”

The right tools for the job

The most impactful opportunities to fight methane will depend on the measures a country has already taken and the industries it relies on. The authors therefore created an online tool to identify the most effective measures for abatement in different countries.

For big fossil fuel producers, regulating production, incentivizing the capture of methane, or charging companies for methane emissions could be the most effective options. For others, focusing on emissions from landfills could offer the biggest rewards. Individuals can help by making lifestyle changes and by thinking about the environment when they vote. The authors however caution that while there are uncertainties, and there is not yet enough data to fully parse out the contributions of individual factors to the recent surge in the observed growth rate, for example, it is imperative to rapidly reduce methane emissions to reduce the accelerating climate damages so many people around the world are suffering.

“We urgently need policies in place that effectively achieve sizable cuts in methane emissions and politicians that are brave enough to implement such policies,” Höglund-Isaksson concludes.

Adapted from a press release prepared by Frontiers in Science.

Reference
Shindell, D., Sadavarte, P., Aben, S., de Oliveira Bredariol, T., Dreyfus, G., Höglund-Isaksson, L., Poulter, B., Saunois, M., Schmidt, G.A., et al. (2024). The methane imperative. Frontiers in Science DOI: 10.3389/fsci.2024.1349770