The major emitter that’s missing from climate negotiations

A new analysis from Senate Majority Leader Chuck Schumer’s (D-N.Y.) office finds that pending infrastructure and budget bills would put the U.S. on track to hit the Biden administration’s targets for greenhouse gas emissions reductions over the next decade. That’s good news. But what if we’re aiming for the wrong target?  

There’s a major source of greenhouse gas emissions that could derail international efforts to limit climate change, yet most people have never heard of it. It isn’t included in most climate models, nor in the calculations of how quickly we need to curtail fossil fuel emissions. It’s called permafrost, and its carbon footprint this century could be on par with unchecked emissions by the likes of Japan, India, the U.S., or even more than all these nations. Excluding such a player from international calculations and negotiations would be unthinkable. And yet, that is precisely what we’ve been doing with permafrost emissions. 

Permafrost is long-frozen soil that has stockpiled immense amounts of carbon over thousands of years. It covers an area almost twice the size of the United States and holds twice as much carbon as is currently in the atmosphere. As the Arctic warms (something it is doing at three times the rate of the rest of the globe). permafrost is thawing — sometimes abruptly and dramatically — and beginning to release carbon dioxide and methane into the atmosphere. As in other parts of the world, Arctic wildfires are increasing in size and intensity, releasing yet more greenhouse gases and thawing more permafrost. The warmer it gets, the more carbon is emitted. And because those greenhouse gases drive even more warming, it can set off a vicious cycle of self-propelled warming. 

The latest report from the UN’s Intergovernmental Panel on Climate Change (IPCC), released earlier this month, noted this important fact more forcefully than ever before. The report states with high confidence that some permafrost regions are already net carbon emitters; that further warming will cause additional permafrost loss and emissions; and that these emissions are irreversible this century. But they note we have only low confidence in estimates of the timing, kinds and amounts of greenhouse gases that will be released. And for this reason, permafrost thaw and its emissions are not accounted for in global carbon budgets that guide emissions reduction schedules aimed at limiting climate warming to thresholds such as those set out by the Paris Agreement. This is a disastrous mistake.

Our research indicates that, depending on how hot we let it get, emissions from permafrost thaw this century are likely to be on par with continued emissions by Japan (on the low end) or by the United States (on the high end). Japan or the U.S. That’s a big difference. But, either way, it’s equivalent to an entire nation — one of the world’s top emitters, no less. To put it another way, permafrost thaw emissions could eat up between 25 percent and 40 percent of our remaining carbon budget to cap warming within 2 degrees Celsius of pre-industrial temperatures. Those numbers go up dramatically if the goal is limiting warming to 1.5 degrees Celsius. To ignore this because we can’t fully constrain it is folly.

As scientists who are documenting the rapid unraveling of the Arctic and know its ramifications for the world, we are calling on federal and international policymakers, as well as our scientific colleagues, to do what is needed to ensure our climate policies are grounded in reality: put estimated permafrost thaw emissions in the global carbon budget now and prioritize permafrost research to improve those estimates over time. We are committed to doing the necessary and important work to better understand permafrost thaw emissions, but we already know that the problem is too big to keep ignoring. We cannot afford to continue burying our heads in the permafrost; it’s thawing too quickly.

Dr. Sue Natali is director of the Arctic Program at Woodwell Climate Research Center and a leader in the field of permafrost thaw research.

Dr. Brendan Rogers is an associate scientist at Woodwell Climate Research Center whose work focuses on northern forests, wildfires and abrupt Arctic landscape changes.