Monday, January 17

The Arctic can’t go back anymore

Figure 1 A report published by AMAP in April of this year as a summary for policy makers.Figure 1 A report published by AMAP in April of this year as a summary for policy makers.

In April of this year, the Arctic Circle Surveillance and Evaluation Program (AMAP), in which scientists studying the Arctic Circle participated, warned strongly that the Arctic Circle is no longer the Arctic Circle. Snow, water, ice, permafrost ”was announced. As global warming progresses, sea ice is decreasing and permafrost is melting. Research in the Arctic is a “no wait” situation. In Japan as well, research on the effects on mid-latitude climate and acidification of the Arctic Ocean has been progressing for the past 10 years. In 2015, the National Institute of Polar Research, Japan Agency for Marine-Earth Science and Technology, and the Ministry of Education, Culture, Sports, Science and Technology’s “Arctic Research Promotion Project (ArCS)” started and are still ongoing.

Changes in the Arctic also affect Japan

The area around the Arctic is expected to be the most intensely warmed by the Intergovernmental Panel on Climate Change (IPCC). According to the Fifth Assessment Report of 2013, if carbon dioxide in the atmosphere continues to increase, the average temperature of the earth will rise by about 4 degrees in 100 years until the end of this century, especially in high latitude areas centered on the North Pole. Then, the temperature rises at twice that pace.

The AMAP report, the first since 2011, highlights three new points from the last six years of research. In the Arctic Ocean in summer, ice may run out in the late 2030s. Sea level rise due to melting of glaciers and ice sheets is likely to exceed the IPCC forecast. And changes in the Arctic will affect mid-latitude weather and even the Southeast Asian monsoon. Japan cannot be irrelevant to the changes in the Arctic region.

There are already irreversible changes in the Arctic

The characteristics of this AMAP report are that the current Arctic climate is shifting to a new state, a fundamental shift, and a new’type’. The point is that it emphasizes that it is already different from the past. “For example, even with sea ice, the decline may not be stopped anymore. Such a view has been strengthened in the last 1-2 years.” Takashi Kikuchi, Deputy Director of the Japan Agency for Marine-Earth Science and Technology’s Arctic Environmental Change Research Center, who participated in the compilation of the report, points out that.

In the Arctic Ocean, where the US and Soviet Union faced during the Cold War, data such as water temperature were military secrets. It was released at the end of the 20th century. As if to fill that gap, research in the Arctic is progressing rapidly.

If there is little sea ice from summer to autumn, Japan will have a severe winter.

In Arctic research, the results of Japanese researchers have contributed significantly from an early stage. For example, the impact of reduced Arctic ice on the climate of distant Southeast Asia. El Nino and La Nina, where the seawater temperature along the equator of the Pacific Ocean deviates from the average, have long been famous as phenomena that affect Japan’s climate. In El Nino, it is cold summer and warm winter, and in La Nina, it is extremely hot and severe winter. A new perspective on Arctic sea ice was introduced in a paper written by Associate Professor Meiji Honda of Niigata University in 2009.

At that time, it was said that in the year when the Arctic Ocean had little ice from summer to autumn, the Far East region such as Japan would become cold next winter. In 2005, when the ice on the Siberian coast was extremely low in September, cold air came to Japan in the winter from that year to the following year, resulting in “2006 heavy snowfall.”

For the first time, Honda et al. Clarified the relationship between Arctic sea ice and mid-latitude weather, including the mechanism of its impact. When the ice in the Arctic Ocean melts, the surface of the sea, which is hotter than the ice, appears. Therefore, in years when there is little ice, the heat of the sea tends to warm the atmosphere. Especially around November when the atmosphere gets cold, heat is actively transferred to the atmosphere in the Barents Sea and Kara Sea in the western coast of Siberia, and as a result, the Far East around December becomes cold. This paper, which combines Arctic sea ice with mid-latitude weather, has since been cited in many papers. It is a proof that has given an important perspective to the research of the Arctic region up to the present.

Severe Arctic Ocean Acidification

When carbon dioxide in the atmosphere increases, not only global warming progresses, but also the “acidification” of the sea progresses. Sea water is slightly alkaline, but when carbon dioxide dissolves in sea water, it approaches neutrality. This is the acidification of the sea. In the sea, there are creatures that make shells and skeletons from calcium carbonate, such as shellfish and corals. As the sea becomes more acidified, the amount of “carbonic acid” (carbonate ion) that is the material for calcium carbonate decreases. Therefore, it can be a big blow to such creatures.

In a 2009 paper, Michiyo Kawai, an associate professor at Tokyokaiyo University, pointed out that the “unsaturation” of seawater is progressing on a large scale in the Canada Basin in the Arctic Ocean. “Supersaturated” has enough “carbonic acid” and “calcium” to make shells and skeletons, and “unsaturated” is lacking. It was known from that time that there were partially “unsaturated” sea areas such as the coast, but the indication that it covers a wide sea area triggered the eyes of researchers to the Arctic Ocean. rice field.

In addition, Kawai et al. Revealed in 2016 that they had been “unsaturated” for quite some time near the bottom of the Chukchi Sea, where the Pacific Ocean waters flowed into the Arctic Ocean. As a result of calculation based on the data from the summer of 2012 to the summer of 2014, when making a shell with calcium carbonate of the type “aragonite” that is easily dissolved in seawater, it becomes “unsaturated” for about 8 months in a year. It was. If we don’t try to reduce carbon dioxide emissions, the Chukchi Sea will continue to be in this state for almost a year by the middle of this century.

Figure 2 Graph showing the Figure 2 Graph showing the “saturation” near the bottom of the Chukchi Sea. The pink region with a saturation level of 1 or less is in an “unsaturated” state where aragonite shells cannot be formed. (Provided by Mr. Kawai)

Knowing this fact, a new mystery was born. A large number of bivalves inhabit the bottom of the Chukchi Sea. Moreover, it also contained small shellfish that were still in the growing stage. Bivalves usually lived in an environment where shells could not be made normally due to “unsaturation”. I still don’t know why. “The seawater in Tokyo Bay is likely to be in this state in 50 years. What is likely to happen in various seas is already a reality in the Chukchi Sea. We can see the future of the earth now. However, it is a great significance of Arctic research, “says Kawai.

Fig. 3 Shellfish collected from the seabed of the Chukchi Sea.  (Provided by Mr. Kawai)Fig. 3 Shellfish collected from the seabed of the Chukchi Sea. (Provided by Mr. Kawai)

The world is paying attention to the fact that if the Arctic sea ice decreases, ships will be able to navigate, but even how much the sea ice will decrease cannot be predicted properly. It is also said that the relationship between the decrease in sea ice from summer to autumn and the severe winter in Japan has recently collapsed. Something new may be born. At AMAP’s parent organization, the Arctic Council, Japan is nothing more than an observer, but “Japan can also contribute to the Arctic Council through scientific research,” says Kikuchi.

Arctic science is a hot field with many unknown territories. Scientists may be waiting for fundamental discoveries that can contribute to the world’s earth sciences, rather than small derivative studies.

(Naoki Hosaka, Science Portal Editorial Department)