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Ice-Breaker: Get to Know the Melting Arctic Sea Ice


Image Source: Carbon Relief


Ice-breakers are somewhat nerve-wracking but fun. You awkwardly exchange questions and perform activities with strangers you just met, gradually learning about each other and becoming friends.


Arctic’s ice-breaker? Not fun at all, but just as important to learn about.


What is Arctic like?


Arctic sea ice is thickest ice during March (end of winter) and thinnest during September (end of summer). Yet despite this variation, the Arctic is frozen year-round.


This supposedly vast barren land of ice actually has many ecological roles!


We all know coastal regions have milder climates because water has higher specific heat than land. But another reason that ocean water regulates coastal temperature is because of the global ocean water circulation, through which freezing cold polar water flows toward the equator and warm equatorial water flows back to the poles. Freezing sea ice drives ocean water circulation by increasing local water salinity which will sink and flow toward warmer equatorial regions.


Moreover, the freezing sea ice also stimulates column mixing, or water mixing between depth. This brought nutrients and organic matters deep within the ocean back to the surface, resulting in a period of phytoplankton growth that establishes a firm base for marine food chain.


Melting sea ice melts release nutrients and increase sunlight penetration, similarly boosting phytoplankton growth.


The permanently freezing ice is also both a natural protection to coastal erosion and the habitat for many organisms such as seals, arctic foxes, polar bears, and penguins. It’s not just some ice.



How are you doing, arctic sea ice?


Arctic sea ice has not been well!


In October this year, Siberian ice in the Laptev Sea, border of the Arctic ocean, reached a record late date to freeze. It’s hard to freeze when both the air and ocean water is warm due to global warming. Laptev Sea is 5 degrees Celsius warmer than usual this year, because the changing global temperature and the ocean circulation pattern pushed warm Atlantic currents into the Arctic. This increased turbulence even caused mixing between the cold Laptev Sea surface water and warm bottom water.


Since 1979, the Arctic is warming at almost twice the global average rate and sea ice has declined by more than 40%. At this rate, scientists predict that before the end of the 21st century, the Arctic will be ice free for part of the year before the 21st century.



What’s the problem?


For one, this is a positive feedback loop that continuously worsen climate change.


The visually white ice reflects more sunlight than visually blue ocean water, because ice has higher reflectivity, or albedo. Lower ice coverage results in more absorption of sunlight, causing the Earth to further warm and melt ice.


More open sea also leads to more mixing between warm and cold water, further warming the surface water to melts ice.


Moreover, the Laptev Sea ice usually drifts toward the Arctic region, where it melts and deposits nutrients for phytoplankton growth. But the thinner ice now melts before it reaches the Arctic, and less nutrients leads to diminished phytoplankton growth thus a reduced capacity to remove carbon dioxide from the atmosphere. All in all, melting sea ice leads to more melting sea ice.


This decreased frozen Arctic region also significantly disturbed Arctic ecosystems.


In Canadian arctic, the retreating ice shelves and warmer ocean water led to an influx of orca whales, who aren’t as well adapted to the freezing condition. Now the orca whales prey on numerous arctic species including the endangered bowhead whale, who are threatened by both the changing climate and a new predator.


In Pacific arctic, walrus are forced to move further north in search of adequate climate, devouring fishes in Barents Sea and forcing them to move north as well.


In Atlantic arctic, arctic fox faces a rapid loss of habitat and prey lemming. The red fox, which traditionally lives south of the arctic fox, is moving north and outcompeting arctic foxes. Worse, they are the targets of many hunters seeking benefits from fur trade. In certain regions, arctic foxes are classified as endangered.


Arctic sea ice is an indispensable part of our Earth. A rapidly disappearing part of our Earth.



Sources

  • https://earthobservatory.nasa.gov/features/SeaIce#:~:text=As%20water%20and%20air%20temperatures,while%20pack%20ice%20floats%20freely.

  • https://e360.yale.edu/digest/arctic-sea-ice-has-still-not-formed-in-siberia-the-latest-date-on-record

  • https://www.worldwildlife.org/stories/as-arctic-ice-melts-orcas-move-in

  • https://www.adn.com/alaska-news/science/2020/09/14/as-arctic-sea-ice-melts-killer-whales-are-increasingly-preying-on-endangered-bowhead-whales-scientists-say/

  • https://www.biologicaldiversity.org/programs/climate_law_institute/the_arctic_meltdown/slideshow_text/arctic_fox.html

  • https://eeas.europa.eu/arctic-policy/eu-arctic-policy_en


Photography by Sahil Sethi, Lucy Grossmann, and others
©2020 by SEEC