New study reveals local drivers of the warming of the Arctic amplified


IMAGE: An international team of researchers, including Professor Sarah Kang (left) and DoYeon Kim (right) at UNIST's School of Urban and Environmental Engineering, revealed that local greenhouse gases …
watch Plus

Credit: UNIST

The Arctic experienced an extreme heat wave during the month of February 2018. The temperature at the North Pole has soared to the melting point of ice, which is approximately 30 to 35 degrees (17-19 degrees Celsius) above of the normal. Recent studies have also been conducted that indicate that the mbad of Arctic glaciers has decreased significantly since the 1980s by more than 70%. These sudden climatic changes affected not only the Arctic regions, but also the nexus between water, food and energy security around the world. This is why climate scientists around the world pay increasing attention to this accelerated warming pattern, commonly referred to as "Arctic Amplification".

An international team of researchers, including Professor Sarah Kang and DoYeon Kim at the UNIST School of Urban and Environmental Engineering, revealed that local concentrations of greenhouse gases appear to be attributable to Arctic amplification.

Published in the November 2018 issue of Climate change of nature, his study on the cause of Arctic amplification shows that local concentrations of greenhouse gases and Arctic climate comments outweigh other processes. This study was led by Project Assistant Leader Malte F. Stuecker of the IBS Center for Climate Physics (ICCP) in Busan, South Korea, and has involved researchers from all over the world, including the United States, Austrailia and China.

Long-term observations of surface temperatures show intensified surface warming in Canada, Siberia, Alaska and the Arctic Ocean relative to the increase in global mean temperature. Arctic amplification is consistent with computer models, simulating the response to increasing concentrations of greenhouse gases. However, the underlying physical processes for intensified warming are still difficult to achieve.

Using complex computer simulations, the scientists were able to refute the hypotheses previously suggested, which emphasized the role of heat transport from the tropics to the poles as one of the key contributors to amplified warming in the Arctic.

"Our study clearly shows that local carbon dioxide forcing and polar feedback are more effective in Arctic amplification compared to other processes," says Assistant Project Leader Malte F. Stuecker, the corresponding author of the study.

Increase in anthropogenic carbon dioxide (CO)two) concentrations trap heat in the atmosphere, which leads to surface heating. Regional processes can amplify or further attenuate this effect, thus creating the typical pattern of global warming. In the Arctic region, surface heating reduces the extent of snow and sea ice, which in turn decreases the reflectivity of the surface. As a result, more sunlight can reach the top of the soil layers and the ocean, leading to accelerated warming. In addition, changes in Arctic clouds and in the vertical atmospheric temperature profile can improve warming in the polar regions.

In addition to these factors, heat can be transported to the Arctic by winds. "We see this process, for example, during El Niño events: Tropical warming, caused by El Niño or by anthropogenic greenhouse gas emissions, can cause global changes in atmospheric weather patterns, which can lead to changes at surface temperatures in remote regions, such as the Arctic. "said Kyle Armor, co-author of the study and professor of Atmospheric Sciences and Oceanography at the University of Washington.

In addition, global warming outside the Arctic region will also lead to an increase in the temperatures of the Atlantic Ocean. Ocean currents, such as the Gulf Stream and the North Atlantic drift, can transport warmer waters to the Arctic Ocean, where they could melt sea ice and experience further amplification due to local processes.

To determine whether changes in tropical warming, atmospheric wind, and ocean current contribute to future Arctic amplification, the team designed a series of computer model simulations. "Comparing simulations with only Arctic COtwo Changes with simulations that apply CO.two Worldwide, we find similar Arctic warming patterns. These findings show that remote physical processes from outside the polar regions do not play an important role, in contrast to the previous suggestions ", says co-author Cecilia Bitz, Professor of Atmospheric Sciences at the University of Washington.

In the tropics, fed by high temperatures and humidity, air can easily rise to great heights, which means that the atmosphere is unstable. In contrast, the Arctic atmosphere is much more stable with respect to the vertical movement of air. This condition improves COtwoInduced heating in the Arctic near the surface. In the tropics – due to the unstable atmosphere – COtwo It mostly heats the upper atmosphere and energy is easily lost in space. This is opposite to what happens in the Arctic: outgoing infrared radiation escapes into the atmosphere, further amplifying the warming of the trapped surface.

"Our computer simulations show that these changes in the profile of the vertical atmospheric temperature in the Arctic region outweigh other regional feedback factors, such as feedback from the ice albedo often cited," says Malte Stuecker.

The results of this study highlight the importance of Arctic processes to control the rate at which sea ice will withdraw in the Arctic Ocean. The results are also important in understanding how sensitive polar ecosystems, the Arctic permafrost and the Greenland ice sheet will respond to global warming.


Notes for editors
The previous material has been provided by the Institute of Basic Sciences.

Contact with the author

Malte Stuecker, IBS Center for Climate Physics (ICC), Busan, South Korea; email: [email protected]; Phone: + 82-51-510-7862.

Journal reference

Stuecker, M. F., C. M. Bitz, K. C. Armor, C. Proistosescu, S. M. Kang, S.-P. Xie, D. Kim, S. McGregor, W. Zhang, S. Zhao, W. Cai, Y. Dong and F.-F. Jin, "Polar amplification dominated by local forcing and feedback", Climate change of nature (2018), doi: 10.1038 / s41558-018-0339-y

About the Institute of Basic Sciences (IBS)

IBS was founded in 2011 by the government of the Republic of Korea with the sole purpose of promoting the development of basic science in South Korea. IBS has launched 28 research centers as of August 2018. There are nine physics, one mathematics, six chemistry, eight life sciences, one earth science and three interdisciplinary research centers.

Source link