This story was originally published by WIRED and is reproduced here as part of the Climate Desk collaboration.
Around 20,000 years ago, the world was so frigid that massive glaciers sucked up enough water to lower sea levels by 400 feet. As the sea pulled back, newly exposed land froze to form permafrost, a mixture of earth and ice that today sprawls across the far north. But as the world warmed into the climate we enjoy today (for the time being), sea levels rose again, submerging the coastal edges of that permafrost, which remain frozen below the water.
It’s a huge, hidden climate variable that scientists are racing to understand. They know full well that the destruction of terrestrial permafrost is a significant source of carbon entering the atmosphere. As it thaws, microbes munch on the organic matter it contains, releasing carbon dioxide (if the material is fairly dry), and methane (if the melted ice forms a pond). This can form a feedback loop, in which more permafrost thaw produces more emissions, which heat the planet to thaw even more permafrost. That’s an extra-big problem because the Arctic is now warming four times a... Read more