Today, methane (甲烷) is a central but under-appreciated part of the fight against climate change. Human activity releases far less methane than carbon dioxide, but methane packs a heavier punch. Over the course of20 years, a ton of the gas will warm the atmosphere about 86 times more than a ton of carbon dioxide. Chief among the reasons for methane emissions (排放) are the gassy output of raising farm animals ( cows release it most) , rice production ( certain environments involve micro-organisms that make it) and the fossil fuel industry( pipelines leak it) .
Carbon dioxide remains in the atmosphere for centuries, making it hard to reduce its concentrations. By contrast, methane has a half-life of roughly ten years. If new emissions can be cut to below the rate at which old emissions reduce, the concentration of methane remaining in the atmosphere will soon fall, slowing global warming.
A big step would be to stop millions of tons of methane from leaking out of fossil fuel industry each year. Natural gas operators will be able to sell more gas in exchange for an acceptable investment so as to monitor and repair leaks. The International Energy Agency estimates that 40% of methane emissions from fossil fuels can be cut at no cost for firms.
The harder task is to reduce emissions from agriculture, but even here farmers can draw on new ideas, including developing new forms of feed for farm animals, and changing how rice field is irrigated.
However, politicians and the public tend to ignore the effects of cutting methane emission. But dealing with the gas with the efforts of the ordinary people would have a large effect at a relatively low cost.