Recent methane growth driven by wetlands, waste, and agricultural emissions, not fossil fuels.

What is it about?

Methane is a potent greenhouse gas, and its accelerating rise since 2006 makes international climate goals harder to meet. However, there is debate about the specific sources driving this recent increase. By combining global records of methane’s hydrogen and carbon isotopic compositions, this study provides strong evidence that microbial sources, such as those from wetlands, agriculture, and waste, are primarily responsible for the post-2006 methane rise, while fossil fuel emissions have remained relatively stable despite increased global production. Our findings highlight the importance of microbial methane sources and their potential sensitivities to changes in climate.

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Photo by Jaanus Jagomägi on Unsplash

Photo by Jaanus Jagomägi on Unsplash

Why is it important?

This study is the first to analyze long-term trends in atmospheric δD-CH₄ together with δ¹³C-CH₄ to directly diagnose the drivers of recent methane growth. Using simple atmospheric models with rigorous uncertainty analysis, we show with high confidence that the 2006–2023 rise in methane is driven primarily by increasing microbial emissions, while fossil fuel emissions have remained relatively stable despite continued growth in oil and gas production. This matters because it provides rare, conclusive source-level evidence for what is fueling methane’s continued acceleration at a critical moment for climate mitigation. The stability of fossil fuel emissions shows that large-scale reductions are achievable, even during industry expansion, and highlights unrealized mitigation potential. At the same time, the rapid increase in microbial methane points to climate-driven feedbacks that could further accelerate warming, increasing the urgency of near-term mitigation.