Converting methane to CO2 may help combat climate change: Study

Converting methane into carbon dioxide could help turn the tide of climate change, according to Stanford scientists who propose that turning one greenhouse gas into another may be a profitable way to combat global warming.

While the idea of intentionally releasing carbon dioxide into the atmosphere may seem counter-intuitive, swapping methane for carbon dioxide is a significant net benefit for the climate, according to the study published in the journal Nature Sustainability.

"If perfected, this technology could return the atmosphere to pre-industrial concentrations of methane and other gases," said Rob Jackson from Stanford University in the US.

In 2018, methane -- about 60 per cent of which is generated by humans -- reached atmospheric concentrations two and a half times greater than pre-industrial levels, previous studies have shown.

Although the amount of carbon dioxide in the atmosphere is much greater, methane is 84 times more potent in terms of warming the climate system over the first 20 years after its release.

According to the researchers, the basic idea is that some sources of methane emissions -- from rice cultivation or cattle, for example -- may be very difficult or expensive to eliminate.

"An alternative is to offset these emissions via methane removal, so there is no net effect on warming the atmosphere," said Chris Field from Stanford.

Researchers claim that removing carbon dioxide is a tough deed with hundreds of billions of tons removed over decades without restoring the atmosphere to pre-industrial levels.

Methane concentrations, on the other hand, could be restored to pre-industrial levels by removing about 3.2 billion tonnes of the gas from the atmosphere and converting it into an amount of carbon dioxide equivalent to a few months of global industrial emissions, according to the researchers.

Methane is challenging to capture from air because its concentration is very low. However, the researchers point out that zeolite, a crystalline material that consists primarily of aluminum, silicon and oxygen, could act essentially as a sponge to soak up methane.

The trapped methane could then be heated to form and release carbon dioxide, researchers said.

The process of converting methane to carbon dioxide could be profitable with a price on carbon emissions or an appropriate policy, researchers said.