There was a record-breaking increase in methane in Earth’s atmosphere last year

Concentrations of a super potent greenhouse gas in the atmosphere — methane — grew tremendously in 2021. It’s still something of a mystery why the world saw such an “exceptional increase” last year, says the World Meteorological Organization (WMO), which released the numbers yesterday.

The reasons for the big leap last year are unclear because methane in the atmosphere can come from many different sources. But we do know who’s consistently responsible for huge amounts of methane pollution. Every year, the oil and gas industry leaks tremendous amounts of methane. There are also natural sources of methane emissions, and climate change can make that a bigger problem. So it’s no wonder methane is building up at astonishing levels in our atmosphere.

2021 marked the biggest year-on-year increase in atmospheric methane concentrations since the WMO started keeping track around four decades ago. With that jump, the amount of methane lingering in the atmosphere in 2021 was 262 percent of what it was before the industrial revolution. And once methane is in the atmosphere, it’s initially 80 times more powerful than carbon dioxide when it comes to heating up the planet. Methane is estimated to have caused about 30 percent of the current rise in global temperatures since the industrial revolution.

Methane is simultaneously a pervasive and elusive pollutant to track. The fossil fuel industry sells it as the “natural gas” used in home heating and cooking stoves. And the gas is constantly leaking from oil and gas fields, pipelines, and even stoves. About 82.5 million tons of methane escaped from the oil and gas industry last year, according to the International Energy Agency.

For a sense of scale, consider what experts estimate is likely the fossil fuel industry’s single-largest methane leak ever — which just happened this month. A nearly half-mile stretch of the Baltic Sea was bubbling with leaking methane after suspected sabotage to the Nord Stream 1 and 2 pipelines. While the cause and severity of that leak make it unusual, the upper estimate of how much gas escaped from the Nord Stream pipelines represents just a small fraction of industrial methane leaks every year. The worst-case emissions scenario for Nord Stream pipelines is equivalent to only two days of routine leaks from oil and gas infrastructure around the world. And there’s plenty of research that suggests that methane leaks are actually underestimated.

Tracking methane emissions gets more complicated because a lot of it also comes from animals and the environment. A cow will belch up around 220 pounds of methane a year, a major source of agricultural greenhouse gas emissions. Methane also wafts up from landfills as organic material decomposes.

The WMO also says that a La Niña weather pattern could potentially have added to the big jump in methane concentrations recorded last year. La Niña can drive more rain in the tropics, an ideal environment for methane-producing microbes in tropical wetlands. But what’s more worrying is the possibility of a dangerous climate feedback loop from wetlands. Rising global temperatures can make wetlands warmer and wetter. Organic material can decompose faster in that warmer climate — and when this happens underwater, it can lead to more methane emissions from microbes that thrive in oxygen-deprived environments.

Taking all of this into consideration, causes of the “dramatic increase” in methane last year “are still being investigated,” the WMO said yesterday. Even so, there are already strategies for stopping so much methane from building up in the atmosphere. Environmental groups have pushed the oil and gas industry for years to patch up leaks and capture any methane that does escape.

But even that won’t be enough in the longer run since economies will need to swap fossil fuels with clean energy to slash enough greenhouse gas emissions to avoid the worst effects of climate change. The world is way behind on that front. Concentrations of the three main greenhouse gases — carbon dioxide, methane, and nitrous oxide — in the atmosphere all hit record highs in 2021, the WMO found.