Rapid thaw of permafrost could release large GHGs
Scientists have warned that vast swaths of permafrost across the Arctic may thaw much before the current projections, releasing vast amounts of greenhouse gasses into the atmosphere.
Scientists know that the arctic and sub-arctic regions are heating up two times faster than the rest of the planet and that it will release perilous amount of methane and CO2 thus far trapped under the ice. But scientists anticipated this process to be slow, giving humans a good chance of cutting down anthropogenic emissions. But a new study published in the journal Nature Geoscience, says that studies done till now have ignored a lesser known phenomenon where ice disintegrates rapidly, sometimes within days. This process is also known as abrupt thaw.
This abrupt thawing will take place in less than 20% of the land under permafrost. But this could increase the CO2 from permafrost melt by over 50%, the study said. Permafrost area was to decrease by 24% projected the IPCC special report published in September 2019, if mean global temperatures did not exceed 2° Celsius by 2100. This sudden thawing could not only release a lot of CO2 but also methane. Methane is many times more potent than CO2.
Permafrost regions experience temperatures below freezing point. They contain a strata of soil and rocks over pockets of ice. It contains organic matter that has never decomposed because of low temperatures. But once they thaw they become a reservoir of greenhouse gasses, including CO2 and methane. In the northern hemisphere it comprises over 25 per cent of the land area. Scientists say that there is 1,500 billion tonnes or carbon trapped in these permafrost regions, which is twice the amount trapped in the atmosphere and three times what humans have emitted since industrialization began. What is also worrying is the fact that some of these regions under permafrost are inhabited by indigenous communities and have industrial infrastructure across the subarctic region, especially in Russia which could be adversely affected.