Arctic Warming from Space
Atmosphere Climate Change Daily Earth Science Hydrosphere Repost

Arctic Warming

Research tells us the Arctic is warming, and most evidence points to the Arctic warming faster than average global temperature rises. Melting ice and permafrost amplify temperature increases by releasing carbon dioxide and allowing oceans to absorb more solar heat. The consequences of this added heat in the Arctic are significant and range from sea level rise to long term variations in seasonal climatic cycles. So living in the Arctic is not a requirement for feeling the consequences of a warmer north pole.  

Arctic warming is significant because it triggers two feedback processes that strengthen the rate of global warming. The first of these processes centers on carbon. The Arctic contains the largest reservoir of carbon on the face of the earth, and that carbon is being stored as organic matter, frozen into thick layers of Arctic soil. So the Arctic permafrost is a ticking carbon bomb waiting to explode.

The earth’s atmosphere contains 850 gigatons of carbon. However, there are an additional 1,400 gigatons of carbon in the Arctic, waiting patiently for release from its frozen cage. Also stored in the Arctic are large reservoirs of methane. Methane is about 20 times more effective as a greenhouse gas than carbon dioxide (CO2).

Bacteria and methane hydrates

Rising temperatures affect these methane and carbon stores in two ways. When the Arctic permafrost thaws, bacteria will start feasting on organic matter in the soil. The byproduct of this bacterial party is CO2 and methane. So temperature increases lead to faster Arctic warming and a higher rate of greenhouse gas release into the atmosphere. The added gases then trap even more heat in the atmosphere. This sort of feedback loop works to amplify global warming.  

The methane reservoirs of the Arctic are held in clathrates (methane hydrates). When temperatures are low, and pressures are high, conditions are ripe for the formation clathrates. During the formation process, large amounts of methane get trapped within water crystals to form a substance similar to ice. Large deposits of these clathrates exist today on the ocean floors, storing methane in a solid form. In the Arctic, these methane clathrates exist in shallow seas and in permafrost. 

Clathrates become unstable and release their methane if the temperature rises or confining pressures drop. If temperatures rise high enough in the Arctic, these clathrates will release their methane payload into the atmosphere, further exacerbating warming. 

Sea ice versus open ocean

There is another feedback loop at work heating the polar environment in a process called Arctic Amplification. This process involves a temperature feedback mechanism from solar radiation. 

The Arctic Ocean is warmer than the atmosphere in the winter, and heat transfers from the warm water to the colder air. Ice then forms on the ocean surface. The ice inhibits heat transfer and acts as an insulator as it thickens. When the ice is thick enough to impede any transfer of heat (about 3 meters), it stops growing. 

Seasonal temperature increases in the summer warm the Arctic, and some of the sea ice melts. If the summer climate is warm enough, the ice will disappear and expose open ocean waters below.

Sea ice has a high albedo and reflects solar radiation back into space.  The darker ocean water is not as reflective as the ice, and it absorbs heat from solar radiation more efficiently than ice. So less sea ice cover equals less reflected solar radiation and increased ocean warming.  Then more ocean heat and a warmer atmosphere inhibit ice formation the next winter. When summer returns, it is easier for the sun to melt the thinner sea ice than the year before. If this cycle continues long enough, sea ice will disappear completely.

Sea ice decline

Sea ice extent affected by Arctic Warming
Figure: Changes Arctic sea ice extent (National Snow and Ice Data Center (NSIDC))

The graph above shows a 40% decrease in Arctic sea ice extent over the past 40 years. Arctic Amplification is not a fantasy; it is already an active component in increasing the rate of climate change. The fabled Northwest Passage that eluded explorers for hundreds of years will become a reality by the mid 21st century. Since the northern polar region exerts a primary control on our planet’s weather systems, we can all expect to experience the results of Arctic warming no matter where we live.


ArcheanWeb

Politics: A tipping point for climate change? (Source: ArcheanWeb) – https://archeanweb.com/2019/12/02/politics-a-tipping-point-for-climate-change/ Also:

Arctic Methane Craters (Source: ArcheanWeb) – https://archeanweb.com/2020/01/08/arctic-methane-craters/


Sources:

Cohen, J., Pfeiffer, K. & Francis, J.A. Warm Arctic episodes linked with increased frequency of extreme winter weather in the United States.Nat Commun 9, 869 (2018) doi:10.1038/s41467-018-02992-9 – https://www.nature.com/articles/s41467-018-02992-9#ref-CR17

Methane Hydrates and Contemporary Climate Change By: Carolyn D. Ruppel (U.S. Geological Survey, Woods Hole, MA) © 2011 Nature Education Citation: Ruppel, C. D. (2011) Methane Hydrates and Contemporary Climate Change. Nature Education Knowledge 3(10):29 –  https://www.nature.com/scitable/knowledge/library/methane-hydrates-and-contemporary-climate-change-24314790/

Source for figure showing changes Arctic sea ice extent – National Snow and Ice Data Center (NSIDC) – http://nsidc.org/arcticseaicenews/2018/10/september-extent-ties-for-sixth-lowest/

William House
William is an earth scientist and writer with an interest in providing the science "backstory" for breaking environmental, earth science, and climate change news.

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