Mandatory mitigation to meet the methane imperative

Published on September 2nd, 2024

The current climate emergency can be described in terms of temperature, time, and tipping points. Last year, 2023, was the warmest year in 125,000 years (1) and there is little time left to bend the warming curve before self-amplifying climate feedbacks push the planet past the many fast-approaching tipping points lurking beyond the 1.5ºC guardrail (2). 

The best (and, so far, the only known) way to change this trajectory and reduce near-term warming, slow self-amplifying feedbacks, and avoid irreversible tipping points, is to make rapid and sustained cuts to methane and other climate super pollutants—hydrofluorocarbons (HFCs), black carbon soot, tropospheric ozone, and nitrous oxide. These super pollutants are responsible for half of current warming (3), with carbon dioxide (CO₂) responsible for the other half. More importantly, reducing the amount of super pollutants in the atmosphere could avoid four-fold more warming at 2050 than reducing CO₂ alone (3). While a double-barreled strategy is essential, cutting the super pollutants alone could slow warming in the near-term of the next two decades, thereby slowing self-amplifying climate feedbacks (3,4) and avoiding, or at least delaying, the tipping points anticipated between 1.5 and 2ºC (2). This is the “super pollutant sprint” the world must win while running the marathon to decarbonize the energy system and reduce CO₂ to net zero. 

The Frontiers in Science lead article “The methane imperative”, by Shindell et al. (5), provides definitive evidence demonstrating methane mitigation’s planet-saving ability to reduce near-term warming. This starts with observational evidence showing that methane growth rates are reaching the greatest values ever recorded—far above levels consistent with the 1.5–2ºC temperature limits of the Paris Agreement—and the recognition that mandatory mitigation measures are therefore needed. 

The authors explain that failure to cut methane will eat up a sizable portion of the remaining carbon budget for 1.5ºC, which, on current course, will be exhausted by 2030. As the carbon budget shrinks, the need for strategies to reduce CO₂ and methane from the atmosphere grows. Bioenergy with carbon capture and storage (BECCS) is the go-to carbon-negative strategy used in many integrated assessment models to balance the budget for 1.5ºC scenarios (6). While BECCS is a “model-derived stopgap” (7), continuing to use it, even as a placeholder inevitably gives it more credibility than it deserves. It is better for policymakers if BECCS is rejected up front, as it leaves a significant carbon deficit in the critical next two decades (8). Planting new forests also does not offer much mitigation in the next two decades, while protecting existing forests does (9); stronger efforts are needed here. 

Given the compelling evidence for its benefit, methane mitigation should be a slam dunk. The fact that it is not leads the authors to double down on the need for legally binding regulations and methane pricing. It is time to move beyond voluntary methane pledges toward mandatory mitigation measures that are fully implemented and robustly enforced.  

Methane has come out of the shadows of climate policy and is now in the spotlight thanks to the seminal Shindell-led Global Methane Assessment, published in 2021 by the United Nations Environment Programme’s Climate and Clean Air Coalition (10), the subsequent Global Methane Pledge later that year together with the launch of the Global Methane Hub, and the agreement at the last climate negotiation in 2023 by 50 oil and gas companies to eliminate flaring and reduce methane leaks to near-zero by 2030. More recently, in May 2024, Pope Francis and a group of governors and mayors from around the world issued the Planetary Call to Action for Climate Change Resilience (11) to cut the rate of global warming in half in the near term, with the “sprint” to rapidly reduce methane and the other super pollutants joined with the “marathon” to zero-out CO₂. 

Despite the spotlight on this issue, current policy mechanisms cover only 13% of global methane emissions (12). The United States and the European Union (EU) have plans for increasingly stringent methane regulations underway, as do a few other governments, and there is a growing fleet of methane satellites to monitor compliance (13). But this is not enough to turn the tide. 

To speed the shift to mandatory methane mitigation, the EU and other major purchasers of natural gas, including Japan, South Korea, and Turkey, could form a buyers club that sets a methane standard equivalent to the soon-to-be announced EU standard that requires sellers to meet the standard or pay a financial penalty.  

This would be a fast way to start addressing methane emission reductions on a global scale. Once underway, it could evolve into a more muscular Montreal Protocol-like sectoral agreement, with separate protocols for fossil fuel methane and for waste methane, with full implementation of the principle of common but differentiated responsibilities, including needed funding. (Methane from the agriculture sector would be best addressed through a shift in subsidies in a separate protocol.) Indeed, in 2021 the European Parliament recommended negotiating “a binding global agreement on methane mitigation … in line with the modelled pathways that limit global warming to 1.5 °C” (14).  

The Montreal Protocol is a persuasive precedent. It is a legally binding global agreement that succeeded in solving the first great threat to the global atmosphere, from the destruction of the stratospheric ozone layer, while also avoiding as much warming as CO₂ is causing (15). By the end of the century, the Montreal Protocol’s steady progress over its 35 years of operation will avoid up to 2.5°C of warming (16)—warming that otherwise would have already pushed the planet past irreversible tipping points. The 2016 Kigali Amendment to the Montreal Protocol to phase down HFC refrigerants will, on its own, avoid up to 0.5°C of warming by 2100 (17). Parallel efforts to improve the energy efficiency of cooling equipment during the switch to climate-friendly refrigerants would double the climate benefits of the amendment (18). 

As the European Parliament’s recommendation for a binding global agreement on methane did not move forward, it is time to reevaluate this. Consider: if methane is the best and probably only way to prevent climate chaos in the near-term as we decarbonize the energy system, how can the world not make the effort to develop a legally binding methane agreement?  

References 

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13. The White House. FACT SHEET: Biden-⁠Harris Administration Announces New Actions to Detect and Reduce Climate Super Pollutants [online] (2024). Available at:  https://www.whitehouse.gov/briefing-room/statements-releases/2024/07/23/fact-sheet-biden-harris-administration-announces-new-actions-to-detect-and-reduce-climate-super-pollutants/

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