Earth’s melting permafrost threatens to unleash a dangerous climate feedback loop

GR: Here are some additional comments on the expanded permafrost-melt findings I reported this morning. That study did not project the effect on global temperature. The article below is by respected climate scientist Joe Romm. Perceptions of the permafrost threat has waxed and waned over the past few years, but I think it has permanently waxed this time. There is one correction. I thought permafrost carbon would be released largely as methane. Romm says there will be a substantial amount of methane, but that most of the gas will be CO2.

In this so-called “drunken forest,” in Alaska, the trees tilt because the once-frozen ground (permafrost) is thawing. CREDIT: NSIDC.

“New permafrost study underscores the critical importance of ambitious climate targets, like the Paris agreement.

“Global warming will defrost much more permafrost than we thought, a new study finds. Every 1°C (1.8°F) of additional warming would thaw one-quarter of the earth’s frozen tundra area — releasing staggering amounts of heat-trapping greenhouse gases (GHGs).

“Those GHGs would in turn warm the planet more, melting more permafrost, releasing more GHGs, and so on. This is perhaps the most dangerous amplifying carbon-cycle feedback humanity faces — considering permafrost contains twice as much carbon as the atmosphere does today.

“That’s why it’s so vital the U.S. adheres to its commitments in the 2015 Paris climate agreement — a landmark accord in which the world unanimously committed to keep ratcheting down carbon pollution to ensure total warming stays “well below 2°C [3.6°F] above pre-industrial levels.” And that’s why President Donald Trump’s efforts to undermine the deal are so dangerous, since they may put the permafrost — and hence our livable climate — across a point of no return.

“Trump’s executive order puts the world on the road to climate catastropheIt’s so egregious, it no longer really matters if he doesn’t formally opt out of the Paris climate deal.thinkprogress.org

“If we could limit total warming to the 1.5°C target identified in the Paris deal, that would save 800,000 square miles of permafrost compared to 2°C warming. But if the Trump administration succeeds in thwarting Paris, then we may lose more than half of the permafrost.” –Joe Romm (More: Earth’s melting permafrost threatens to unleash a dangerous climate feedback loop.)

Global Warming Could Thaw Far More Permafrost Than Expected

GR: Here’s your daily dose of bad news for climate change. This study doesn’t consider the effect of the increased permafrost thaw. However, we know that thawed permafrost releases methane and other gasses. Expect new global-warming projections soon. (Link to recent post concerned with extent of permafrost thaw.)

Thawing permafrost has communities like Newtok, Alaska literally losing the ground under their feet. Credit: Getty Images

“More than 40 percent of the world’s permafrost—landscape covered in frozen soil—is at risk of thawing even if the world succeeds in limiting global warming to the international goal of 2 degrees Celsius, according to a new study.

“Currently, permafrost covers about nearly 5.8 million square miles, and scientists found as much as 2.5 million square miles of that could thaw—about twice the area of Alaska, California and Texas combined—in a 2 degree Celsius scenario. Thawing would be more limited if warming can be held to 1.5 degrees Celsius, but could still affect 1.8 million square miles.

“The new research was published Monday in the journal Nature Climate Change.

“Permafrost contains vast amounts of carbon in the form of plants that died since the last ice age and have remained frozen rather than decomposing. When permafrost thaws, this long-trapped carbon is released into the atmosphere, further propelling future warming. A 2015 study estimated that the thawing permafrost could release up to 92 gigatons of carbon into the atmosphere by the century’s end.

“This new study did not estimate the greenhouse gas emissions that would be released from the thawing, or how those emissions could then spur greater rates of permafrost loss in a vicious cycle. Instead, the international team of scientists focused on how warming air temperatures would affect the extent of permafrost. They said their calculations suggest a much more extensive loss than previously thought.” –Zahra Hirji (Continue: Global Warming Could Thaw Far More Permafrost Than Expected, Study Says | InsideClimate News.)