Climate change could accelerate the release of greenhouse gases.
Carbon and methane are now trapped in underwater permafrost.
The deposits formed towards the end of the Paleolithic Ice Age and were covered by 120 m of sea water some 18 000-14 000 years ago, according to the US Geological Survey (USGS). This is reported by Live Science.
The author of the study, from Brigham Young University, Syedeh Sar Syedi, said most of the permafrost is on the continental shelf beneath the Arctic Ocean. However, scientists do not know how much carbon and methane are under the shelf, or how quickly these gases penetrate the ocean and atmosphere.
According to some scientists, this reservoir of greenhouse gas is a time bomb that could trigger another climate catastrophe.
Sayedi and her colleagues disagree with such conclusions and believe that instead of a sudden release, these gases have been slowly and steadily seeping out of the permafrost over the centuries.
“Human-caused climate change could still worsen the situation by increasing the rate of emission, but this acceleration would occur over several centuries, not decades,” Sayedi said.
The team of scientists has compiled the most detailed picture of the submarine permafrost using currently available information. In addition, the scientists asked 25 permafrost scientists to estimate how much organic carbon is hidden in each specific layer of permafrost.
After collecting all the data, the scientists found out that permafrost currently contains about 60 billion tons of methane and 560 billion tons of organic carbon.
Scientists estimate that about 140 million tons of carbon dioxide and 5.3 million tons of methane are released from the permafrost into the atmosphere each year. However, the figures may not be accurate.
Scientists said the rate of greenhouse gas emissions from submarine permafrost will increase over the next 300 years if carbon emissions continue at the same rate. The permafrost will emit four times the amount of greenhouse gases if emissions continue to rise over the 21st century.
Scientists have said there could be a new ocean on Earth.