Surface warming and wetting due to methane’s long-wave radiative effects muted by short-wave absorption

Allen, R.J., Zhao, X., Randles, C.A., Kramer, R.J., Samset, B.H., & Smith, C. ORCID: (2023). Surface warming and wetting due to methane’s long-wave radiative effects muted by short-wave absorption. Nature Geoscience 10.1038/s41561-023-01144-z.

[thumbnail of s41561-023-01144-z.pdf]
s41561-023-01144-z.pdf - Published Version
Available under License Creative Commons Attribution.

Download (10MB) | Preview


Although greenhouse gases absorb primarily long-wave radiation, they also absorb short-wave radiation. Recent studies have highlighted the importance of methane short-wave absorption, which enhances its stratospherically adjusted radiative forcing by up to ~ 15%. The corresponding climate impacts, however, have been only indirectly evaluated and thus remain largely unquantified. Here we present a systematic, unambiguous analysis using one model and separate simulations with and without methane short-wave absorption. We find that methane short-wave absorption counteracts ~30% of the surface warming associated with its long-wave radiative effects. An even larger impact occurs for precipitation as methane short-wave absorption offsets ~60% of the precipitation increase relative to its long-wave radiative effects. The methane short-wave-induced cooling is due largely to cloud rapid adjustments, including increased low-level clouds, which enhance the reflection of incoming short-wave radiation, and decreased high-level clouds, which enhance outgoing long-wave radiation. The cloud responses, in turn, are related to the profile of atmospheric solar heating and corresponding changes in temperature and relative humidity. Despite our findings, methane remains a potent contributor to global warming, and efforts to reduce methane emissions are vital for keeping global warming well below 2 °C above preindustrial values.

Item Type: Article
Research Programs: Energy, Climate, and Environment (ECE)
Energy, Climate, and Environment (ECE) > Integrated Assessment and Climate Change (IACC)
Depositing User: Luke Kirwan
Date Deposited: 27 Mar 2023 09:06
Last Modified: 27 Mar 2023 09:06

Actions (login required)

View Item View Item