Methane, a short-lived but potent greenhouse gas, was discovered in 1776 by physicist and chemist Alessandro Volta. On a fishing trip on Lake Maggiore, he noted that bubbles were rising to the surface in the shallow and marshy waters, and thus identified methane gas, a product of plant decomposition. At the time of his discovery, it is unlikely that Volta could have imagined that methane and other greenhouse gases could change the climate system and, consequently, the dynamics and structures of wetlands, including Lake Maggiore. Writing in Nature, Shushi Peng and colleagues indicate that the warmer and wetter wetlands over the Northern Hemisphere are now a dominant source of methane1. However, the increasing contribution of the natural wetlands to the atmospheric methane concentration should not divert attention away from the importance of anthropogenic sources.

Methane bubbles in lake ice, Lena Delta. Credit: Torsten Sachs.

The energy, food, agriculture and waste emissions reduction pathways are critical to achieving the Global Methane Pledge (GMP)2 — the global goal of cutting methane emissions by 30% by 2030 from the 2020 level. As of November 2022, 150 countries had joined the pledge. In the same month, the United Nations Environment Programme and the Climate and Clean Air Coalition released a report that addresses what would happen to methane emissions without global commitments. The report includes baseline projections that reflect the impact of current policy as well as the implications for achieving the GMP target. The results are not surprising: without additional efforts, agriculture emissions, primarily from livestock and, to a smaller extent, rice cultivation, will continue to rise by 2030 up to 5–16% from the 2020 level; emissions from the oil and gas sector are expected to increase by 3–17% by 2030; and similarly, solid waste and wastewater emissions are expected to rise by 6–18%. The Middle East, Africa and Asia may see the most substantial growth in methane emissions with increases across all sectors3.

While various technical, ecological and social solutions are available4, ground-based and satellite-based data may help to navigate where and when to implement them. For example, a recent analysis in the Proceedings of the National Academy of Sciences used high-resolution inverse analysis of satellite and surface observations to infer China’s methane emissions during 2010–2017. The study found opposing trends in methane emissions — decreasing in the southeast due to the closure of small coal mines, while increasing in the north due to the consolidation of large coal mines. At the same time, there was an unexpected increase in emissions from rice cultivation over east and central China. These trends were not previously detected in national inventories5.

These ground- and satellite-based technological advances are valuable inputs to local governments in formulating detailed and site-specific methane-reduction policies. However, whether this will be enough to achieve the GMP goal is still an open question. In a Comment in this issue of Nature Climate Change, Paul Stern and colleagues argue that science can help to meet emissions targets by providing decision-makers with a scientifically grounded feasibility assessment of the possible course of action that is timely and accurate, reducing disciplinary biases about policy preferences and assumptions. They suggest that feasibility assessments involve three steps: adoption, implementation and responsiveness (also called behavioural plasticity). Developing feasibility assessments of different methane-reduction initiatives will result in policies and actions that are effective in theory and practice.

With scientific knowledge, technological resources and the commitment of 150 countries to the GMP, further delay in reducing methane is unacceptable. As we know, the benefits of mitigation go well beyond avoided warming and pledges being met and are essential for a sustainable future. Let 2023 be the year of methane mitigation progress.