On Monday, The United Nations Intergovernmental Panel on Climate Change has rejected a significant report on the state of the planet which – warning of the spoiler –it doesn’t look great. The main negative of the assessment is carbon dioxide, but it is also called CO2is a lesser known brother: methane. Atmospheric concentrations of this greenhouse gas, which are 80 times stronger than CO2, are now larger than any time in at least 800,000 years, the report notes. If humanity could take a serious approach to reducing methane emissions, it would put a huge and rapid brake on climate change.
“Methane is the next crucial, rapid reward for climate stabilization,” Rick Duke, senior director and liaison for the White House, told President’s Special Envoy for Climate Change, at a press conference Monday after the report was released. “There is simply nothing that could secure our short-term climate future, buy us key time to decarbonise energy and to develop advanced options, such as negative emission technologies. ”
“Reducing methane emissions is the only fastest and most effective way to slow down the warming rate right now,” agreed Ilissa Ocko, a senior climate scientist at the Environmental Protection Fund.
As well as carbon dioxide, methane contains carbon; its chemical formula is CH4. It is a major component of natural gas and many ecosystems. Rotten vegetation produces methane – wetlands are especially emitted. And when insects like termites and ungulates like cows digest food, they also produce methane. (Mostly it is cow belching, not farts, which contain gas.)
But while CH4 is a perfectly natural component of the Earth’s atmosphere, the amount now added to the sky is far from natural. One big factor is livestock, including not only cows but also sheep and pigs – all that manure adds more methane. In the United States, this “enteric fermentation” is responsible for the end a quarter of domestic methane emissions. Production and transportation of natural gas, coal and oil make up another 30 percent, and landfills – which are eventually full of decaying vegetation – add 17 percent.
When determining how strong a greenhouse gas is, there are two main considerations: how efficient the molecule is in capturing heat and how long it can survive in the atmosphere. Greenhouse gases such as CO2 and CH4 both are very effective in retaining heat; they are actually what helps the Earth to be habitable by preventing heat from escaping into space. But methane is better at it. “You have carbon bound to two oxygen atoms in CO2 molecule, but carbon bound to it four hydrogen atoms in the methane molecule, ”says environmental scientist Matthew Hayek, who studies methane. “And so there are several ways in which the bonds between these atoms can vibrate when they receive or absorb infrared radiation, and therefore re-emit infrared radiation.”
“Half a kilogram of released methane can capture heat 100 times more than CO2 when it is first aired, ”agrees Tianyi Sun, a climatologist with the Environmental Fund that specializes in methane. But, she points out, methane disappears faster. “It’s only been in the atmosphere for about ten years and it’s gone.” In contrast, carbon dioxide can last for centuries.
Before humans began to produce too much of each, when these gases appeared naturally, they would float in the atmosphere, absorb radiation, and decompose by oxidation in different time frames. So volcano can eject CO2 into the atmosphere, and the swamps would slowly boiling methane, but both would eventually dissipate. The atmosphere could exist in balance, creating a kind of blanket that kept the planet warm but not too hot.