Study shows permafrost emissions must be included in global climate goals
Arctic permafrost contains a lot of carbon, which may be released as the world warms. Here, the tundra near the Greenland ice sheet in summer. (Kevin Krajic/Earth Institute)
By the end of the century, permafrost in the rapidly warming Arctic could emit as much carbon dioxide and methane into the atmosphere as a large industrial nation, and over time, may exceed what the United States has emitted since the beginning of the Industrial Revolution quantity.
But that’s just one possible future for the massive carbon storage locked in the Arctic’s previously perennially frozen ground but is now melting.Using more than a decade of integrated science and regional models, a new study is published in Annual Review of Environment and Resources Projected cumulative emissions from permafrost to 2100 under low, moderate and high warming scenarios.
“We hope these projections of future Arctic carbon emissions will not only update the scientific picture, but also provide new guidance for policymakers working to stabilize the climate and avoid exceeding temperature goals,” said lead author Ted Schuur of Northern Arizona University.
The team estimates that under a low-temperature-warming scenario — which can be achieved if the global community limits warming to 2 degrees Celsius or below by reducing fossil fuel emissions — permafrost would release 55 billion tons of greenhouse gases by the end of the century . form of carbon dioxide and methane. If nothing is done to mitigate the warming, the study estimates the Arctic could release 232 metric tons.
The team’s predictions surpass previous international predictions by taking into account hydrological and biogeochemical dynamics, as well as tipping points specific to permafrost regions.
For example, scientists are witnessing sudden thawing of many permafrost regions, where the rapid thawing of ground ice in the permafrost causes the surface to collapse. This can form lakes or cause other changes in surface hydrology. Once the previously frozen ground erodes or sinks, the carbon stored there can enter the atmosphere through microbial respiration. This rapid, non-linear change rapidly and permanently alters the permafrost’s ability to store carbon and could shift large swathes of the Arctic from absorbing carbon to releasing it. Recent estimates suggest that one in five permafrost terrain is currently vulnerable to sudden thawing.
“Once there’s an increase in permafrost carbon emissions as the climate warms, as some models predict, there’s nothing we can do to stop that process,” said an atmospheric scientist at Columbia Climate Institute’s Lamont-Doherty Earth Observatory, co-author of the paper. Author Rosin Corman said. and Assistant Professor of Earth and Environmental Sciences. “We may need to reduce fossil fuel emissions sooner than many governments are currently planning to avoid triggering a possible tipping point for the planet’s climate.”
The potential to cross regional and system-wide tipping points is one reason why the story of Arctic carbon and its future security is still only partly written. The new study describes nine different futures based on the progress of climate warming and the actions global leaders are taking to reduce fossil fuel emissions.
“Whichever possible scenario materializes, permafrost emissions will be an important contributor to atmospheric greenhouse gases,” said study co-author Guido Grosse of the Alfred Wegener Institute in Potsdam, Germany. “But there will be huge differences between mitigation scenarios that are important to the overall global carbon budget.”
Because the Arctic is not regulated by any country and its remoteness makes it difficult to monitor comprehensively, the authors stress that international efforts to reduce emissions must take the region into account in future climate goals and actions.The study also highlights the importance of monitoring the region using collaborative networks such as Permafrost Carbon Network And scientific tools such as remote sensing technology.
“Remote sensing products can really help us physically see and track what’s happening in the permafrost,” Commane said. “High-resolution sensors can see evidence of thermal karst soil collapse, how water bodies are changing, and even how wet or frozen the soil is. But satellites that can tell us how much carbon in permafrost ends up in the atmosphere are limited, and space agencies need to quickly identify Invest in those capabilities.”
Shure said his field team is going through rapid change. This summer, at a study site on Eight Mile Lake in Alaska, they witnessed widespread permafrost thaw following a winter with record snowfall, with carbon losses four times the average of past decades.
The study was co-authored by scientists from more than a dozen other institutions in the United States, Canada and Europe. Part of the work was supported by the National Science Foundation.
Adapted from a press release from Northern Arizona University.
