No sooner had I posted a piece about “The Other Greenhouse Gases,” than more new data bubbled up about one of them; methane.
According to a study published by researchers at MIT, there was a global spike in atmospheric methane last year. The increase, on the order of millions of metric tons, was uniform around the world, not concentrated around major methane emitters, as one might expect. In other words, “background” methane levels are up all over, so that the atmospheric concentration is nearly 1800 parts per billion.
That’s a much lower concentration than carbon dioxide, which stands at about 385 parts per million. Methane also breaks down faster in the atmosphere. But it worries climatologists because it is far more potent than CO2 as a greenhouse gas; anywhere from 25 to 50 times more harmful, depending on how you measure it. Researchers Matthew Rigby and Ronald Prinn say atmospheric methane levels have more than tripled since the Industrial Revolution but has held steady in recent years. Recently something has thrown it out of balance but the MIT team could only speculate about possible reasons.
Methane escapes from a combination of both natural and human-induced sources. It leaks from oil & gas industry infrastructure and landfills, and is produced by livestock (and human) digestion. It’s also released by marshes and rice paddies. California is a major rice producer but the rice fields’ share of total U.S. methane emissions is relatively tiny.
Climate Watch is preparing an upcoming feature on methane and climate change. Listen for it on The California Report in November.