Arctic permafrost may unleash carbon
Washington: Permafrost in the coldest northern Arctic will thaw enough to become a permanent source of carbon to the atmosphere this century, with the peak transition occurring in 40 to 60 years, a NASA study warns.
The region was formerly thought to be at least temporarily shielded from global warming by its extreme environment.
The study, led by Nicholas Parazoo of NASA's Jet Propulsion Laboratory in California, calculated that as thawing continues, by the year 2300, total carbon emissions from this region will be 10 times as much as all human-produced fossil fuel emissions in 2016.
Permafrost is soil that has remained frozen for years or centuries under topsoil. It contains carbon-rich organic material, such as leaves, that froze without decaying. The study found that warmer, more southerly permafrost regions will not become a carbon source until the end of the 22nd century, even though they are thawing now. That is because other changing Arctic processes will counter the effect of thawing soil in these regions, researchers said. The finding that the colder region would transition sooner than the warmer one came as a surprise, according to Parazoo.
"Permafrost in southern Alaska and southern Siberia is already thawing, so it is obviously more vulnerable," he said.
"Some of the very cold, stable permafrost in the highest latitudes in Alaska and Siberia appeared to be sheltered from extreme climate change, and we did not expect much impact over the next couple hundred years," said Parazoo.