Arctic debate | The world faces an enormous task

It is difficult to predict when and whether summer ice in the Arctic will disappear. If the goal of the Paris Agreement is achieved, it will likely be saved.

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Arctic ice is known to be melting due to emissions of greenhouse gases into the atmosphere. Using satellite data, we already in 1996 published in the professional journal “Nature” that the thaw had begun. Together with Klaus Haselmann, this year’s Nobel Prize winner in Physics, we published in the professional journal Tellus in 2004 that summer ice (in September) would melt during the post-industrial CO2 doubling, when the CO2 level would be around 0.0560 percent. The level is currently 0.0416 percent. This is based on Hasleman’s global climate model.

A doubling of carbon dioxide to 0.0560 percent is much higher than what is required under the Paris Agreement, where the level of carbon dioxide must be cut to just over 0.0400 percent to keep global temperature below 2 degrees Celsius. An enormous task for the world.

In CO2 this seems small, as the atmosphere contains about 99 percent oxygen and nitrogen with water vapor as the most important greenhouse gas. This is difficult to control, but we can do so in part through emissions of carbon dioxide into the atmosphere, which is the challenge ahead.

Sjukurv Manabe, who shared the Nobel Prize with Haselmann, calculated in the 1950s that doubling the concentration of carbon dioxide in the atmosphere would increase the global temperature by two degrees Celsius. This illustrates the important role of carbon dioxide in increasing global temperature, which in turn influences, for example, rising sea levels, changes in precipitation and drought, severe weather, melting ice in polar regions, not least the global economy and living standards.

Today, the evolution of the ice can be followed in real time day by day using several operational satellite systems, and many national and international groups post this daily on their websites. One of these is the Arctic-Roos Group, led by the Nansen Center in Bergen.

Summer ice volume reaches its annual minimum in mid-September, and in 2012 the minimum was 4.275 million square kilometers. Then it varied, but at least on September 16 of this year, it was 5551 million square kilometers. This means a sharp increase of 1,276 million square kilometers compared to 2012, and a significant increase of 1,131 million square kilometers from 2020.

This is likely due to natural variations with a slightly cooler temperature over the Arctic Ocean this summer, which then compensates for global warming.

This summer’s ice may also be affected by the “Atlantic Perpetual Oscillation,” which we showed in 2016 had an effect on Arctic temperature, and thus also ice melting and freezing that modifies CO2 warming. The “Atlantic Perpetual Volatility” is an expression of the sea surface temperature of the North Atlantic Ocean over a period ranging from 60 to 80 years. This increased from 1910 to 1940 and coincided with the sharp rise in temperature and decrease in ice in this period. Then it decreased with decreasing temperature and increasing ice until 1970, and then increased. Besides warming carbon dioxide, it caused a warmer Arctic with less ice in the following years.

Until this year, when the summer ice grew again.

Recent research has shown that the “North Atlantic Permanent Fluctuations” are on the verge of reversing and regressing, which will slightly lower the temperature and lead to more ice over the next 30 to 40 years, thus modifying the warming of carbon dioxide. But after this period, it may shift again and contribute to more warming and less ice, a hypothesis I proposed in a BA job in October 2018. This has proven difficult to simulate in global climate models.

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Only time will prove

There have been many publications since our work was published in 2004, and many have predicted, using global models, that summer ice will actually disappear within ten years. But global models are bad for the evolution of Arctic temperatures and ice. The results show a high prevalence of when summer snow melts, with a difference of ten to more than 80 years depending on the model and scenario used.

So it is difficult to predict when the summer ice will disappear, if it will melt at all. If the Paris Agreement is achieved by reducing carbon dioxide emissions into the atmosphere, summer ice will likely be saved. “There will be no turning point.” Only time will prove it.