Long-term success requires that NDCs be aggressive in terms of ambition and comprehensive in terms of gasses and sectors covered. We call upon nations to include all GHGs in the next NDCs and specify additional ambitious quantitative contributions from methane and other non-CO₂ gasses; this is a critically important opportunity to increase overall mitigation ambition, to deliver reduced near-term warming, and to obtain important societal co-benefits.
PxD and IGSD are partnering on an initiative to collaboratively identify opportunities for innovation in climate change mitigation, particularly for the greenhouse gases most problematic in agricultural production, methane, and nitrous oxide, as well as carbon dioxide. This initiative includes four analytical pieces on the opportunities for climate change mitigation by smallholder farmers.
Methane is second only to carbon dioxide in its contribution to global warming, and accounts for about half of the temperature increase of human-induced global warming (0.51 °C out of the present 1.06 °C). Strong, rapid, and sustained methane reductions are key to slowing warming in the next two decades, thereby reducing the risks of triggering self-amplifying feedbacks (such as thawing of the permafrost in the Arctic) and of crossing irreversible tipping points (including loss of tropical reefs, the Amazon rainforest, the Greenland Ice Sheet, and the West Antarctic Ice Sheet). Growing recognition of the urgency to reduce methane emissions has propelled over 150 countries to endorse the Global Methane Pledge, which sets a collective target to reduce global methane emissions by at least 30% from 2020 levels by 2030. Achieving this target would reduce warming by at least 0.2 °C by 2050 and keep the planet on a pathway consistent with the goals of the Paris Agreement.
The focus of this brief is on identifying methane mitigation approaches currently suitable for implementation in smallholder farmer and pastoralist contexts.
The remaining carbon budget framework tracks progress towards the Paris Agreement’s goal to limit longer-term warming to well below 2 °C, but no analogous framework exists for constraining mid-century warming. Established single-basket methods of combining gases into CO2-equivalents using Global Warming Potentials (GWPs) lead to ambiguity over what combination of short- and long-lived emissions reductions are needed because they obscure the distinct warming impacts of each. We investigate to what extent a multi-basket approach that separates short-lived and long-lived pollutants can better estimate the likelihood for emission pathways to meet a near-term warming goal. We develop logistic regression models to categorize IPCC emission pathways (AR6) based on whether they exceed a mid-century temperature threshold. We focus on two baskets, using CO2 for long-lived and methane (CH4) for short-lived gases. For comparison, we consider several single-basket approaches (e.g. GWP100, GWP20, GWP*). We further apply our framework to a synthetic dataset covering a broader emissions space. Across both datasets, the two-basket outperforms all single-baskets. Using an illustrative near-term goal (1.7 °C), the two-basket approach reduces the magnitude of overshoot by a factor of 7 compared with the traditional single-basket. The two-basket’s advantage is smaller with the AR6 pathways, which we attribute to the high correlation between CO2 and CH4 emissions and confounding effects from other pollutants. Our results indicate that the two-basket approach better constrains overshoot magnitude, particularly if future emissions deviate from the AR6 assumption of correlated CO2 and CH4 reductions. Our approach allows the determination of a metric value and reduction target in the context of a chosen set of scenarios and temperature threshold; the outcome is a near-term methane-specific emissions budget that can be adopted by decisionmakers in a way that is analogous and complementary to the carbon budget. Future work could consider a third basket for very short-lived pollutants.
Anthropogenic methane (CH4) emissions increases from the period 1850–1900 until 2019 are responsible for around 65% as much warming as carbon dioxide (CO2) has caused to date, and large reductions in methane emissions are required to limit global warming to 1.5°C or 2°C. However, methane emissions have been increasing rapidly since ~2006. This study shows that emissions are expected to continue to increase over the remainder of the 2020s if no greater action is taken and that increases in atmospheric methane are thus far outpacing projected growth rates. This increase has important implications for reaching net zero CO2 targets: every 50 Mt CH4 of the sustained large cuts envisioned under low-warming scenarios that are not realized would eliminate about 150 Gt of the remaining CO2 budget. Targeted methane reductions are therefore a critical component alongside decarbonization to minimize global warming. We describe additional linkages between methane mitigation options and CO2, especially via land use, as well as their respective climate impacts and associated metrics. We explain why a net zero target specifically for methane is neither necessary nor plausible. Analyses show where reductions are most feasible at the national and sectoral levels given limited resources, for example, to meet the Global Methane Pledge target, but they also reveal large uncertainties. Despite these uncertainties, many mitigation costs are clearly low relative to real-world financial instruments and very low compared with methane damage estimates, but legally binding regulations and methane pricing are needed to meet climate goals.
Full citation: Shindell D, Sadavarte P, Aben I, Bredariol TdO, Dreyfus G, Höglund-Isaksson L, Poulter B, Saunois M, Schmidt GA, Szopa S, Rentz K, Parsons L, Qu Z, Faluvegi G and Maasakkers JD. The methane imperative. Front Sci (2024) 2:1349770. doi: 10.3389/fsci.2024.1349770
Cutting methane emissions is the fastest way to slow warming in the near term and keep the goal of limiting global warming to 1.5°C within reach. Methane plays an increasingly important role in China’s responses to climate change. This paper reviews a number of measures aimed at reducing its methane emissions China has adopted over the past few years and outlines significant opportunities remaining to maximize China’s climate mitigation impact.
Fast action to mitigate non-CO2 climate pollutants, such as methane, including through implementing methane intensity requirements (such as via procurement specifications) for domestic and imported oil and gas, can have a significant role in reducing the likelihood of triggering catastrophic climate impacts as countries pursue carbon-neutrality goals. Without robust monitoring, reporting, and verification (MRV) of methane emissions, we will not be able to know the efficacy of methane mitigation policies and programs or whether we are meeting methane mitigation targets. Acting quickly to ensure that new investments in oil and gas infrastructure are built with enhanced MRV systems and methane intensity requirements in mind is essential to limiting risks of stranded assets and aligning with carbon-neutrality goals.
The IGSD Primer on Cutting Methane provides decision-makers with clarity on the science of methane mitigation and why action is urgently needed; current and emerging mitigation opportunities by sector; national, regional, and international efforts that can inform emergency global action on methane; and financing initiatives to secure support for fast methane reduction. This Methane Primer provides the scientific and policy rationale for decision-makers to achieve the “strong, rapid, and sustained” cuts to methane emissions necessary to slow global warming in the near term and limit the risk of triggering tipping points. The Methane Primer also supports the need for research and development of technologies to remove methane from the atmosphere at scale.
The Global Methane Assessment shows that human-caused methane emissions can be reduced by up to 45 per cent this decade. Such reductions would avoid nearly 0.3°C of global warming by 2045 and would be consistent with keeping the Paris Climate Agreement’s goal to limit global temperature rise to 1.5 degrees Celsius (1.5˚C) within reach.
The assessment, for the first time, integrates the climate and air pollution costs and benefits from methane mitigation. Because methane is a key ingredient in the formation of ground-level ozone (smog), a powerful climate forcer and dangerous air pollutant, a 45 per cent reduction would prevent 260 000 premature deaths, 775 000 asthma-related hospital visits, 73 billion hours of lost labour from extreme heat, and 25 million tonnes of crop losses annually.
