Given the urgent need to slow down global warming, researchers suggest choosing the lesser of two evils when it comes to greenhouse gases. Carbon dioxide traps heat, but methane is much more potent at the task, so they suggest converting it into carbon dioxide to help fight climate change.
The counterintuitive idea, outlined in Nature Sustainability, would drag the concentration of methane in the atmosphere back down to pre-industrial levels. That would reduce global warming by one-sixth, the researchers say.
Most climate efforts focus on carbon dioxide, but methane is in some ways a worse offender. While it does not last as long as carbon dioxide in the atmosphere, it traps 84 times as much heat in the first two decades. Agriculture and livestock are the biggest source of methane emissions, followed by oil and gas production and use.
Removing methane would kickstart the reduction of global warming, say the researchers. And that “would buy us considerable time to address the [larger] problem of carbon dioxide emissions,” Rob Jackson, a professor of earth system science at Stanford University told Technology Review.
Jackson and his colleagues propose removing methane from the atmosphere and oxidizing it to produce carbon dioxide. This would turn 3.2 billion metric tons of methane into 8.2 billion metric tons of carbon dioxide, which is just a few months’ worth of the 40 billion tons of carbon dioxide emissions the world produces each year.
The challenge of capturing methane from air is that its concentration is very low. But the researchers recommend using zeolite, a highly porous material made mainly of aluminum, silicon and oxygen, to soak up methane.
They envision giant renewable-powered arrays of electric fans that push air into chambers full of the zeolite. Heating the catalyst in the presence of oxygen would then create carbon dioxide that can be released into the air.
Of course, this is a purely hypothetical idea. More research will be needed to determine if it is technologically and economically viable. Plus, removing methane, or carbon dioxide for that matter, from the atmosphere would not be a replacement for reducing emissions in the first place. “It’s a concept at this stage, and won’t be cheap,” the researchers write in a commentary, “but it would add to the tool kit needed to tackle climate change.”
Source: R. B. Jackson et al. Methane removal and atmospheric restoration. Nature Sustainability, 2019.