This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: In a new report, the United Nations Environment Program (UNEP) concludes that global warming is expected to exceed 1.5°C within the next few years. This makes two questions increasingly important: how high will temperatures rise, and how long will the increase last?
In a separate international study published in npj Climate Action, Chalmers researcher Daniel Johansson and his colleagues investigated a potential future method for limiting peak warming: removing methane directly from the atmosphere. "Methane removal could provide a way to temporarily reduce peak warming, but it is not a permanent solution. If we stop removing methane, the warming returns.
It is therefore important to see methane removal as a potential complement to deep emissions reductions and permanent carbon dioxide removal, not as a shortcut around them," says Johansson, professor at the Department of Environmental and Energy Sciences. Reducing methane emissions is an important climate measure. The study investigates a different and far more experimental possibility: removing or breaking down methane that is already in the atmosphere.
Carbon dioxide is the most important long-lived greenhouse gas driving global warming. Methane is present at much lower concentrations and remains in the atmosphere for a shorter period, but it is also a very powerful greenhouse gas. Reducing methane concentrations can therefore affect global temperatures more quickly than reducing carbon dioxide concentrations.
The researchers compared three types of climate intervention: The model calculations show that methane removal could lead to a relatively rapid reduction in global temperature. If methane removal is stopped, temperatures begin to rise again, although the rebound in warming is less abrupt than when solar radiation management is terminated. With carbon dioxide removal, the climate effect persists because the model assumes that the carbon dioxide already removed from the atmosphere is stored permanently.
One question for future research is what role atmospheric methane removal (AMR) could play in relation to solar radiation modification in the future. "Solar radiation management is associated with significant risks and uncertainties and is therefore a highly controversial option. At the same time, the consequences of warming above 1.5°C are serious," says Johansson.
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