Thanks to the warm summer heat, the Arctic ice sheet reaches its minimum every September. Since the end of the century this minimum has become more and more pronounced. According to NASA data, based on several of its satellites, the extent of the polar ice cap has decreased by 12.6% every decade since 1980. However, due to climate variability itself, it is difficult to know when the entire Arctic Ocean will consist of water. Now, a study based on observations from NASA and ESA satellites and a sophisticated climate model predicts that the first ice-free September will come between 2030 and 2050. And if greenhouse gas (GHG) emissions are not reduced, the Arctic region will be ice-free for almost half a year by 2100.
Until the turn of the century, attempting to navigate the Northwest Passage (connecting the Atlantic Ocean to the Pacific Ocean through northern Canada) was an adventure confined to the summer and aboard an icebreaker ship. The situation was somewhat better in the Northeast Passage (through the far north of Russia), where the ships could sail a few months a year. Nowadays, both routes are relatively safe in the summer, so there is an increasing number of tourist cruises on old icebreakers. But the Arctic Ocean resists being circumnavigated: Even today, the Transitional Sea, the part that connects to North Greenland, remains frozen all year round. But ships could even reach this area and the center of the North Pole in just a few years, according to a new study published today in the journal Nature Communications.
“We assume that in all emission scenarios we consider, the Arctic Ocean will be ice-free in the summer between 2030 and 2050,” says the researcher at the Climate Change Research Laboratory of the University of Pohang (South Korea) in an email. Seung-Ki Min, co-author of the study. It must be borne in mind that the future emissions scenarios are in line with the target of not exceeding the 2°C additional warming authorized in the 2015 Paris Agreement. This is the most optimistic scenario, so the thaw seems inevitable. But it also means that, as Min says, “we can avoid an ice-free Arctic in the summer if we can reduce greenhouse gas emissions more aggressively, such as the alternative path to 1.5 degrees warming.” The problem is that According to various studies, this limit for the increase in global mean temperature has already been exceeded regionally and could be exceeded globally in less than five years.
More information
The work, led by Min, is based on Arctic ice evolution tracked by various satellites, with data from 1979 through 2019. One of the contributions of these 40 years of data is this, at least since the end of the decade since the 1990s For years, the ice cap has been losing ice every month, not just in summer. Since the end of the last ice age, the annual cycle of the Arctic has followed the same pattern: Arctic sea ice extent peaked between March and April, decreased in the following months, and reached its minimum between September and October, when it returned to the starting cycle. But all data suggests that the frozen portion of the ocean is getting smaller with each new March, so melting occurs even in the coldest years, albeit marginally.
“Previous work looked at melting throughout the year, but our study confirms that the decline in Arctic sea ice in all months is mainly due to the increase in man-made greenhouse gases,” said Min. This is the other big contribution of this one Work, the affirmation of human responsibility. It is the sun, its rays and its heat that are melting the Arctic sea ice. However, there are active ingredients that can weaken or increase the effect of solar radiation. The natural atmospheric factor that has the most impact is volcanic emissions. The particles act as sun protection and cooling. Other particles caused by industry, automobiles and human warming also play a role. They have found that neither natural nor artificial particles matter: their cooling capacity cannot counteract the warming caused by carbon dioxide (CO₂) and the rest of the greenhouse gases.
“Almost all of the melting we have observed over the past few decades has been caused by us humans”
Dirk Notz, Deputy Director of the Institute for Oceanography at the University of Hamburg
The deputy director of the Institute of Oceanography at Universität Hamburg, Dirk Notz, is one of the leading experts on Arctic ice dynamics. In fact, he was one of the lead authors of the sixth and final report of the Intergovernmental Panel on Climate Change (IPCC) and co-author of the section on ocean, cryosphere and sea level. Notz is also a co-author of this new study on Arctic melting and emphasizes human responsibility: “We have put the human impact on the massive sea ice loss observed in the Arctic at up to 90%.” That means that almost all of the melting that we see observed over the last decades was caused by us humans.”
The authors of the work used the latest system for modeling climate evolution, known as CIMP6, which is capable of running multiple climate models simultaneously, with huge amounts of data and large computational efforts. To validate their results for the future, they compared the results obtained from CIMP6 over the past 40 years and compared them to the actual results recorded by the satellites. “We have seen that in all future scenarios considered, including the most optimistic scenario with significant reductions in greenhouse gas emissions, the Arctic will be ice-free for the first time by September before 2050. This means it is already too late to proceed.” Protecting the Arctic summer sea ice as a landscape and as a habitat: It will be the first major component of our climate system that we will lose through our emissions.”
Even if the time beyond 2050 is accompanied by greater uncertainty, the situation will only get worse as the century progresses. The study predicts that under the worst of the expected climate scenarios (in which greenhouse gas emissions are not reduced and the current emission rate is maintained), the Arctic will be ice-free between May and October by the year 2100. The consequences of half a year without an arctic ice pack would be far-reaching.
Despite appearances, melting ice will not cause sea levels to rise. Unlike the land ice accumulated in Greenland or Antarctica, the Arctic ice is already in the water, so there is nothing to worry about here. But so many months without ice will accelerate climate change: Frozen water has the largest albedo effect in nature after snow. This turns the North Pole into a giant mirror that reflects much of the sun’s radiation, cooling the region. But when a sea enriched with oxygen from freshwater thaws, it darkens and absorbs more solar energy. So, the melting ice caused by global warming amplifies global warming.
The consequences for the environment have been observed since the beginning of the century. Many marine mammals require a minimum amount of ice to breed and rest (e.g. seals and elephant seals) or to hunt, e.g. B. arctic foxes and bears. In principle, an ice-free Arctic Sea for half the year could be good for the large marine mammals, the whales. But after the thaw, people will come. Shipping companies, mining companies, fishing boats, tourist cruises… The unfolding thaw is unleashing a series of geopolitical movements that could reshape much of the world order.
“An ice-free Arctic Ocean means competition for resources and shipping across what China has dubbed the Polar Silk Road could become a reality sooner than expected.”
Kristina Spohr, Professor of International History at the London School of Economics (UK)
“An ice-free Arctic Ocean means competition for resources (fishing, oil and gas exploration) and shipping along what China has dubbed the Polar Silk Road could become a reality sooner than expected,” says Professor of International History at the London School of Economics ( United Kingdom) Kristina Spohr. Speaking from Berlin, where he spoke at a panel discussion on Russia, the war in Ukraine and the Arctic, Spohr believes that “there will be more tension between what are considered international and national open waters: international waters need to be managed in a new way and manner” fisheries, maritime transport, exploration from the seabed); but national waters and ports will raise security concerns and therefore we will see more militarization, but it will also attract non-Arctic actors such as investors in ports and other infrastructure and mining resources (China, but also Japan, Singapore, Southeast Asia, India and European Countries).
For this geopolitics expert, “the melting of the Arctic and the thawing of the world order due to climate change, the war in Ukraine, and tectonic shifts in the international balance of power, while China and Russia push for a world order that follows the West and a multipolarity that transcends goes beyond the rules enacted after the fall of the wall [de Berlín]poses risks for the indigenous peoples of the Arctic, for the ecology, the regional flora and fauna and the situation of the region in general.” A region that, as Spohr recalls, “since the late 1980s was considered a zone of exceptional peace”, protected through ice.
you can follow THEME on Facebook, Twitter and Instagram, or sign up here to receive our weekly newsletter.