Arctic warming fuels dangerous methane feedback loop

The Arctic, known for its icy landscapes and frozen permafrost, is rapidly transforming due to the intensifying effects of climate change. As temperatures rise, a silent but potent threat emerges: methane emissions. Unlike carbon dioxide, methane is not as widely discussed, yet its impact on global warming is profound.

A new study published in the journal Nature highlights the growing concern over methane emissions in the Arctic and their role in creating a feedback loop that could accelerate climate change.

Why methane traps more heat

Methane isn’t as abundant as carbon dioxide, but it’s far more potent. Over a century, it traps 30 times more heat.

Xin (Lindsay) Lan, a climate scientist at CU Boulder’s Cooperative Institute for Research in Environmental Sciences (CIRES), sees the urgency.

“Methane is a very potent greenhouse gas that we need to address urgently,” Lan said. “Our study suggests that a significant portion of the recent rise in atmospheric methane originates from natural sources driven by climate change. Our emission reduction efforts need to be more aggressive.”

Arctic methane levels climb steadily

For years, Lan has tracked methane levels at NOAA’s Global Monitoring Laboratory in Boulder. Methane emissions have steadily climbed since 2007.

Scientists had pointed fingers at fossil fuels, responsible for 30% of emissions. Yet, Lan’s research points elsewhere – to tiny, ancient microbes thriving in new, warmer habitats.

Archaea – microbes that have lived for millennia in wetlands, landfills, and the guts of livestock – produce methane. They may be small, but they’re mighty emitters. Microbial emissions now make up nearly half of all global methane output. Yet, pinpointing specific sources remains tricky.

Lan isn’t just watching long-term trends. Seasonal fluctuations in methane also reveal what’s changing underground.

Permafrost fuels methane emissions

Lan’s team dove into decades of data. Methane’s seasonal amplitude – the swing from highest to lowest levels in a year – is shrinking in northern latitudes.

Why? Wetlands in the Arctic are expanding. Thawing permafrost is unlocking ancient carbon stores, creating perfect conditions for archaea.

Computer models show the Arctic’s wetlands have grown by 25% in the warmer months, feeding the microbes with more decomposing organic matter. The result: more methane.

The feedback loop accelerates

When permafrost melts, more carbon enters the atmosphere. As temperatures rise, more permafrost melts. A cycle begins. Lan’s research shows that since 2007, this loop has intensified. What was once a trickle of methane is becoming a flood.

“This study, along with a few previous studies, has provided indirect evidence on potential climate feedback on methane emissions, which would be beyond our ability to control directly,” Lan said.

In previous work, Lan’s team analyzed connections between today’s methane surge and dramatic warming events that ended past ice ages.

As Arctic ice sheets melted, vast stores of methane escaped, causing rapid temperature increases. That was thousands of years ago. Now, it’s happening again – but faster.

Underestimated methane removal

Methane doesn’t linger forever. Hydroxyl (OH) radicals act like atmospheric scrubbers, breaking down methane. Lan’s team discovered that since 1984, these radicals have increased by 10%.

Unfortunately, OH levels are hard to measure – they disappear within seconds – scientists had assumed they remained constant. But Lan’s study suggests that the atmosphere has been removing more methane than previously thought.

“Our result showed that we’ve been underestimating how much methane the atmosphere has been removing, which means that there’s actually more methane being emitted than we previously estimated,” Lan said.

Arctic methane feedback loop

If the atmosphere is cleaning itself more efficiently, then methane emissions are higher than we realized.

That’s a big problem. Emission reduction plans rely on accurate data. If those numbers are off, efforts to control methane may miss the mark.

Lan stresses that understanding methane’s sources is critical. Microbial emissions are surging, but fossil fuels still account for a major chunk of global output.

And the Arctic’s permafrost holds double the carbon currently in the atmosphere. If warming continues, thawing permafrost could unleash catastrophic carbon releases.

“We need to aggressively cut all greenhouse gas emissions from the sources we can control,” Lan said. “We need to address the feedback loop before reaching that tipping point.”

Urgency amid uncertainty

Time is not on our side. Methane’s rise mirrors past warming events, but this time, human activities amplify the effect.

Lan’s work highlights a critical truth: the Arctic is changing faster than expected, and methane is slipping through the cracks.

Now, the question is – how much longer before the feedback loop spirals beyond control?

The study is published in the journal Nature.

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