Ice-free Arctic summers may indeed be inevitable, even if climate promises are kept

This is clear from a New analysis led by South Korea, Tuesday in Trade Journal Nature Communications. Melting Arctic ice will not raise sea levels – floating sea ice does not affect this – but it will change the local landscape. For example, polar bears will find it difficult to hunt, more algae growth and acidification may occur in the sea, and reduced sea ice may alter ocean currents.

“Frankly, we don’t really know what the effect is yet,” says oceanographer Laura de Staur of the Norwegian Polar Institute, on the phone from Tromsø, who was not involved in this study.

In recent decades, the ice in the Arctic has melted again during the summer area smaller than ever: 6.5 million square kilometers of ice in the 1990s, 5.4 million in the years 2001-2010, 4.4 million in the 2010s. Still an area larger than India, but faster than climate models provided.

A team led by climatologist Seung-Ki Min of the University of Pohang is now correcting this by fine-tuning models for satellite observations since 1979. As early as 2030, there’s a one-in-twentieth chance that the ice surface under what appears to be a million square kilometres. She will come. This is a limit that scientists call “nearly ice-free,” although there is still a larger ice surface than France.

Even with strong reductions in greenhouse gas emissions, this will almost certainly happen regularly around 2050. There is also a growing possibility that the Arctic will remain ice-free for months on end. Under temperate climate policies, the Arctic will be ice-free sometime around 2060 or 2070 regularly from July to October.

“These are very strong conclusions,” says de Store, after reviewing the study. “The chance that we will see such an ice-free September in 2030 is very small,” she asserts. But it can also go fast. The difference from year to year is significant. For example, if there is a year in which northerly winds push sea ice far to the south, things go fast. This happened in 2012, the record year that sea ice shrank to “only” 3.4 million square kilometers in late summer.

dark water

The Intergovernmental Panel on Climate Change got involved his last report It is still assumed that the Arctic region will remain covered in ice under very strict weather measures. In all other cases, the pole will likely be regularly ice-free sometime around 2070, and it will likely experience an ice-free summer before 2050. The new research moves those years forward by about ten to twenty years.

Although the Arctic will freeze again in winter, it will only become much more difficult. “Because the darker seawater absorbs more heat, you can have a longer ice-free period,” says de Store. With the current climate approach, the first ice-free month of July could fall as early as 2040, and the first ice-free October five years later, according to charts drawn by the South Koreans.

An ice-free pool is also expected to attract freight traffic via the Northern Shipping Route from Asia. Environmentalists and climatologists see this with suspicion: after all, the risk of oil spills and pollution increases with container ships. “And you’re in a remote area, far from all the assistance systems,” says de Store.

air pollution

Almost all of the melt acceleration can be attributed to an increase in greenhouse gases, the researchers calculate. Ironically, humans are also pushing back on ice reduction: without air pollution blocking sunlight, melting would have accelerated another 23 percent. Natural factors, such as volcanic eruptions or fluctuations in solar activity, have had no effect on the downturn over the past 40 years.

In the journal, the researchers solemnly write: ‘Our findings underscore the massive impact of greenhouse gas emissions on the Arctic, and illustrate the importance of preparing for and adapting to an Arctic that will be ice-free for a season in the near future. ”