麻豆传媒

The warming of our planet is usually blamed on carbon dioxide, but there is another major greenhouse gas contributing to the havoc in our skies too: methane. There is far less methane being emitted into the atmosphere than CO₂, but during its first 20 years there, methane鈥檚 warming effect is more than 80 times greater.

As it is emitted from livestock and leaky pipes, methane also reacts with nitrous oxides to make the gas ozone close to Earth鈥檚 surface. Here, ozone causes people breathing problems and .

If we could scrub the air of methane, it would help stop temperatures rising, buying us some time to reduce our other carbon emissions. For every billion tonnes of methane removed from the atmosphere, Earth鈥檚 surface temperature would be reduced by a roughly 0.2掳C, according to from . 鈥淚t鈥檚 not easy, but if we can work out the chemistry, I think it鈥檚 a fantastic opportunity,鈥� says Jackson.

Technologies for capturing CO₂ have been around for years. The gas given off in power station flues can be trapped by binding it to solvents in a reversible chemical reaction, and that CO₂ can then be imprisoned deep underground. But those same solvents can鈥檛 absorb methane as easily. One reason for this is that methane molecules are a different shape, meaning those solvent molecules don鈥檛 pack around them so easily.

One solution is to forget about capturing methane and instead chemically convert it to CO₂. Releasing extra CO₂ into the air might sound foolish, but given how bad methane is, it may be a positive move. 鈥淓very molecule of methane released into the air eventually ends up as carbon dioxide anyway,鈥� says Jackson. 鈥淎ll we鈥檙e trying to do is speed up the transition.鈥� Most US states are already using this idea to tackle methane leaking from landfill sites, using a cover impregnated with microbes that convert methane to CO₂.

Alternatively, we might employ zeolites, materials that are riddled with atomic-scale tunnels that molecules can fit inside. Certain zeolites can absorb methane and then catalyse a reaction that turns it into methanol, which can be used in the chemical industry. Chemists have already . This technology isn鈥檛 mature, but Jackson thinks it has great promise.