“These are really interesting and important results,” says Rachael Byrom, a climate scientist at the CICERO Center for International Climate Research in Oslo who wasn’t involved in the new study. Nonetheless, she says, “methane still remains a really key gas that we need to target in emissions reductions.”

Humans are responsible for most of the methane entering the atmosphere, where it worsens global warming. Concentrations of the potent greenhouse gas have risen about 162 percent since preindustrial times, according to the U.S. National Oceanic and Atmospheric Administration.

The largest sources of anthropogenic methane include fossil fuel use, livestock, rice farming, landfills and biomass burning (SN: 9/29/22; SN: 7/14/20). Scientists fear that as warming triggers thaw of permafrost in the Arctic regions, this could also lead to increased methane emissions, as microbes in the soil consume dead plant material and release the gas (SN: 9/25/19).

Rising methane

The concentration of methane (CH₄) in the atmosphere, measured in parts per billion, continues to increase. The gas absorbs radiation, worsening global warming.

Global monthly average of atmospheric methane, 1983–2021

Greenhouse gases like methane exert their strongest effects by absorbing infrared “longwave” radiation emitted from the planet’s surface. Earth emits this longwave radiation when it is struck by “shortwave” radiation coming directly from the sun. Most studies of greenhouse gases focus on longwave absorption.

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