Tuesday, 1 September 2026

Global methane emissions would need to drop by at least 69% by 2050 from 2020 levels to hold warming to 1.7C under a scenario where CO2 reaches net-zero in 2050, according to a study published in Communications Earth & Environment and described by its authors in a guest post for Carbon Brief.

The study takes a different route from the usual practice of bundling the two gases together. Its authors write that they "decouple" CO2 and methane reduction and take global warming limits as the starting point for determining the required level of methane cuts.

Run the other way, the arithmetic is unforgiving. Even under the most ambitious existing national net-zero targets, the study finds that an absence of methane reduction leads to peak warming that exceeds 1.85C above pre-industrial levels. That result holds despite the CO2 ambition already pledged, which is the point the authors press: methane is not a residual line item that CO2 policy absorbs.

Methane is the second-largest contributor to global warming after carbon dioxide, the authors note.

National climate pledges rarely separate it out. Only a few countries, including Japan, Mexico and South Korea, specify methane mitigation targets, according to the Carbon Brief guest post. The gap between that short list and the 69% cut the study identifies is the practical problem the paper puts in front of negotiators.