Snow is at risk: Permafrost will almost disappear by 2100

Accurate understanding of mechanics Permafrost It is necessary to assess and mitigate the potential impacts of future deterioration. However, existing predictions have large uncertainties.

Studies of how the Earth has historically responded to the last warm periods are useful for exploring possible future behavior and for assessing the uncertainty of future projections. Now, an international team of scientists has compared current climate trends with the planet’s climate 3 million years ago and concluded Most permafrost near the Earth’s surface will disappear by 2100.

The team found that the amount of permanent ice near the surface could decrease by 93% compared to the pre-industrial period from 1850 to 1900. The Intergovernmental Panel on Climate Change’s latest report calls it the most extreme warming scenario.. By 2100, permafrost near Earth’s surfaceWithin 10 to 13 feet above the soil layer, It was probably confined to the eastern Siberian highlands, the Canadian High Arctic Archipelago, and the northern tip of Greenland during the warm period of the mid-Pliocene.

research, which has just been published Proceedings of the National Academy of Sciences (PNAS)., directed by Donglin Guo of the Chinese Academy of Sciences and Nanjing University of Information Science and Technology. Scientists from the United States, Russia, England, Germany, Japan, Canada, the Netherlands, France and Sweden collaborated in this research.

“Our study indicates a dramatically smaller land mass than in the geological past, consistent with climate conditions expected if global warming continues unabated,” said Vladimir Romanovsky, an expert professor emeritus of the Fairbanks Institute of Geophysics. One of the co-authors, the University of Alaska, is also a leader in permafrost research.

“Losing much of the surface over the next 77 years will have wide-ranging implications for human livelihoods and infrastructure, the global carbon cycle, and surface and subsurface hydrology.”

“This research – continued the expert Another warning sound More about what’s going on Earth’s climate. Climate simulations of the mid-Pliocene warm period are similar to climate projections for the end of this century under the fossil fuel-driven growth trajectory in the Intergovernmental Panel on Climate Change’s (IPCC) latest report. This path is the darkest of the five presented for future society.

Simulations of the mid-Pliocene warm period in 2100 and projections of permafrost extent in 2100 focus only on near-surface permafrost, which is less resistant to climate warming than deep permafrost. Ten computer models predict that Earth will lose 77% of that permanent ice by 2100 if surface air temperatures rise by 10 degrees Celsius, compared to the 1995-2014 period, according to the IPCC’s fossil fuel-driven growth trajectory.

The paper’s authors chose to compare Earth’s projected future with the mid-Pliocene, which occurred about 3 million years ago, because it was the most recent period of sustained global warming in the planet’s geologic history.

Scientists have no direct information about the permafrost of the Northern Hemisphere during the warm period of the mid-Pliocene. To overcome this, they analyzed other factors such as vegetation composition and special soil properties to reconstruct surface air temperature records. From that indirect evidence, they estimated the permafrost extent of the mid-Pliocene warm period.

Using computer models, they determined that global average annual surface temperatures at that time were 14 to 15 degrees warmer than pre-industrial times. It also showed that temperatures in Arctic regions were almost 10.5 degrees warmer.

The absence of permafrost is also inferred from marine fossil sediment records in northwest Alaska, the paper notes. The authors show that the simulated winter and summer temperature and precipitation variables, which have the largest influence on permafrost stability, are similar for the mid-Pliocene and for the years 2100 and 2200. Climate factors can improve our understanding of the magnitude, dynamics, and uncertainty of permafrost loss in a warmer future climate.

“Based on our findings,” Romanowski adds, “the future of near-surface permafrost in the Northern Hemisphere looks bleak. Continued climate warming and associated degradation may result in changes in environmental conditions that humans have not yet experienced, implying the imperative to further highlight the importance of its degradation,” he concluded. .