Context: As per the data from US National Snow and Ice data Center (NSIDC), the combined extent of Arctic and Antarctic sea ice dropped from 15.93 million sq km to 15.76 million sq km in marking a record low.
Relevance of the Topic: Prelims: Questions based on climate change and climatology.
About Sea Ice Cover
- There are two major sea ice spots in the world, the Arctic and Antarctic. Arctic sea ice covers 40% of total global sea ice. Whereas, Antarctic sea ice accounts for 60% of total global sea ice due to its extensive seasonal fluctuation.
- Role of sea ice in maintaining climate:
- Enhancing albedo: The white ice helps in reflecting back the insolation, enhancing albedo. This helps in maintaining the global temperature.
- Absorbing heat: The sea ice absorbs the subsurface heat in the ocean. This reduces the average ocean temperature.
- Prevents ocean acidification: By reducing the ocean temperature, sea ice cover helps in reducing the carbonification of ocean water. This in turn helps in maintaining health of corals, across the globe.
Extent of ice dip in Arctic and Antarctic (As per the study)
- According to the NSIDC, an estimate of 77,800 sq km of ice has been lost per year since the late 1970s.
- Arctic: Between 1981 and 2010, Arctic sea ice extent in September (when it reaches its minimum) shrunk at a rate of 12.2% per decade.
- Antarctica: Until 2015, the region actually witnessed a slight year-on-year increase in sea ice. But, between late 2014 and 2017 the Antarctic lost two million square km of sea ice, i.e., an area equivalent to roughly four times the size of Spain.
Reasons behind the dip:
- Oceanic and Atmospheric changes: The studies suggested the subsurface warming of the Southern Ocean has pushed the Antarctic sea ice melt.
- Transformed wind pattern: Changes in the wind patterns can influence sea ice extent by pushing warmer water. The transformed wind pattern in the Arctic, sea ice remained low because of the delayed freezing around the Hudson Bay.
- Increased ocean heat loss: Less ice means more open ocean, which accelerates further melting of ice, due to rise in absorption of heat.
- Storms and higher air temperature: The regions like the Barent sea witnessed some storms due to which the Arctic ice has become thinner and more fragile over the years. Also, higher than usual air temperatures in areas such as Svalbard, Norway resulted in further loss of sea ice.
Implications of sea ice loss
- Climate regulation: Antarctica sea ice plays a crucial role in regulating earth’s climate by reflection. A decrease in the sea ice alters these dynamics, potentially accelerating global warming.
- Ecosystem impact: The loss of ice affects the habitat of various polar species (like Polar Bear and Penguins), disrupting food chains and threatening biodiversity.
- Sea level rising: While sea ice melt does not directly contribute to sea level rise leading to further vulnerability and climate change induced migration. (E.g., Indonesia changed its capital from Jakarta due to the threat of sea level rise.)
Understanding the contributing factors for dip in ice cover and its potential consequences is essential for developing effective mitigation and adaptation strategies.