The Alaskan tundra is warming so quickly it has become a net emitter of carbon dioxide ahead of schedule, a new study finds.
Since CO2 is the primary heat-trapping greenhouse gas — and since the permafrost contains twice as much carbon as the atmosphere does today — this means a vicious cycle has begun that will speed up global warming.
“Because it’s getting warmer, there’s more CO2 coming out which means it’s going to get warmer which means there’s more CO2 coming out,” explained Harvard researcher and lead author Roisin Commane. Dr. Commane told ThinkProgress that “warming soils will emit more CO2 and this will overwhelm any CO2 uptake” due to an increase in plantlife from “CO2 fertilization and warmer temperatures.”’
The study is the first to report that a major portion of the Arctic is a net source of heat-trapping emissions. As a result, Commane warns that our current climate models need to be updated: “We’re seeing this much earlier than we thought we would see it.”
“We find that Alaska, overall, was a net source of carbon to the atmosphere during 2012–2014,” the study concludes. Data from NOAA’s Barrow Alaska station “indicate that October through December emissions of CO2 from surrounding tundra increased by 73 percent since 1975, supporting the view that rising temperatures have made Arctic ecosystems a net source of CO2.”
The permafrost, or tundra, has been a very large carbon freezer. For a very long time, it has had a very low decomposition rate for the carbon-rich plant matter. But we’ve been leaving the freezer door wide open and are witnessing the permafrost being transformed from a long-term carbon locker to a short-term carbon un-locker.
“This is ancient carbon,” Dr. Commane told Alaska public radio. “The carbon that’s locked in the permafrost in the Arctic is thousands and millions of years old.”
Thawing permafrost can release not just CO2, but also methane, a much stronger heat-trapping gas.
While most models that include thawing permafrost look at CO2, Russian scientists have recently discovered some 7,000 underground bubbles of permafrost-related methane in Siberia. Since methane traps heat 86 times more effectively than CO2 over a 20-year span, these findings suggest that the effect of the thawing permafrost is even greater than first thought.
Also, a 2008 study, “Accelerated Arctic land warming and permafrost degradation during rapid sea ice loss,” found that rapid sea ice loss — as has been experienced since the study was published — could triple the rate of Arctic warming.
Meanwhile, the rapid Arctic warming that is fueling these emissions continues. On Monday, NASA reported that April 2017 was the second-hottest April on record — only April 2016 was hotter. As the map above shows, Arctic temperatures were blistering, up to 13.5°F (7.5°C) above the 1951–1980 average.
The longer we delay aggressive climate action, the harder it will be to stuff all the toothpaste back into the tube, and the more catastrophic climate impacts we will face.
This post has been updated for clarity. Dr. Commane reached out to ThinkProgress to make clear that this process would not lead to a runaway greenhouse effect, but would exceed any increase in CO2 uptake from the increase in plant matter expected in the region due to climate change.