Trapped within Earth’s permafrost – ground that remains frozen for a minimum of two years – are untold quantities of greenhouse gases, microbes, and chemicals, including the now-banned pesticide DDT. Permafrost is melting at an increasing pace as the planet heats. Scientists are confronted with many uncertainties when trying to determine how the thaw will affect the environment.
A PaperThe current state of permafrost research was examined in a paper published in Nature Reviews Earth & Environment earlier this year. The paper highlights the conclusions regarding permafrost freeze and outlines the research that is being done to address these questions.
Infrastructure is already being affected by thawing permafrost. This has caused massive sinkholes, collapsed telephone poles, damaged roads, runways, and toppled tree branches. More difficult to see is what has been trapped in permafrost’s mix of soil, ice, and dead organic matter. Research has looked at how chemicals like DDT and microbes – some of which have been frozen for thousands, if not millions, of years – could be released from thawing permafrost.
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Then there is thawing permafrost’s effect on the planet’s carbon: Arctic permafrost alone holds an estimated 1,700 billion metric tons of carbon, including methane and carbon dioxide. That’s roughly 51 times the amount of carbon the world released as fossil fuel emissions in 2019. Plant matter frozen in permafrost doesn’t decay, but when permafrost thaws, microbes within the dead plant material start to break the matter down, releasing carbon into the atmosphere.
“Current models predict that we’ll see a pulse of carbon released from the permafrost to the atmosphere within the next hundred years, potentially sooner,” said Kimberley Miner, a climate researcher at NASA’s Jet Propulsion Laboratory in Southern California and lead author of the paper. But key details – such as the quantity, specific source, and duration of the carbon release – remain unclear.
The worst case scenario is one in which all carbon dioxide and methane are released within a short time period, such as a few years. Another scenario is the gradual release carbon. Scientists are able to better predict the likelihood of any scenario by gathering more information.
While the review paper found that Earth’s polar regions are warming the fastest, it was less conclusive on how increased carbon emissions could drive drier or wetter conditions in the Arctic. It is certain that changes in the Arctic, Antarctic and other regions will lead to lower latitudes. Earth’s polar regions help stabilize the planet’s climate. They drive heat transfer from the Equator to higher latitudes. This results in atmospheric circulation, which powers the jet stream and other currents. A warmer, permafrost-free Arctic could have untold consequences for Earth’s weather and climate.
An integrated approach
Scientists are increasingly turning to integrated approaches to understanding the effects of the Thaw. Earth observations from ground, the air, and space – techniques outlined in the paper. Each approach has its pros and cons.
Ground measurements can be used to monitor changes in a specific area. Space-based and airborne measurements can cover large areas. Ground and airborne measurements focus on the specific time they were collected, whereas satellites constantly monitor Earth – although they can be limited by things such as cloud cover, the time of day, or the eventual end of a satellite mission.
Scientists hope to use measurements from a variety of platforms to create a more complete picture of changes at poles, where permafrost is melting the fastest.
Miner is currently working with colleagues in the field to characterize the microbes that have been frozen in permafrost. Other instruments are being used to measure greenhouse gases like methane emissions using airborne instruments. In addition, airborneSatellite missions and other satellite missions can be used to pinpoint the problem. Emission hotspotsPermafrost regions
Satellite missions that provide higher resolution data on carbon emissions are also in the works. The ESA (European Space Agency), Copernicus Hyperspectral Imaging Mission (ESA) will map changes to land cover and help monitor soil and water quality. NASA’s Geology and surface biologyThe satellite-based imaging spectrum of the (SBG), mission will also be used to collect data about research areas, including plants and their health; changes in land due to events such as landslides and volcano eruptions; and snow, ice accumulation, melt and brightness, which is related to how heat is reflected back into space.
SBG is the focus area of one of several future Earth science missions that make up NASA’s Earth System Observatory. These satellites will provide a holistic 3D view of Earth from the surface to the atmosphere. They will provide information on topics such as climate change and extreme storms.
“Everyone is racing as fast as they can to understand what’s going on at the poles,” said Miner. “The more we understand, the better prepared we will be for the future.”
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