The melting of Arctic sea ice

(MainsGS3: Conservation, environmental pollution and degradation, environmental impact assessment.)

Context:

• The recent studies stated that loss of Arctic sea ice is inevitable in the decades ahead, even if the world somehow gets its act together and sharply reduces carbon emissions.

Importance of Arctic sea ice:

• The United States’ Environmental Protection Agency (EPA) explains the importance of sea ice.
• It stated that “Sea ice is light-coloured and therefore reflects more sunlight back to space than liquid water, thus playing a vital role in keeping polar regions cool and maintaining the earth’s energy balance. 
• Sea ice also keeps the air cool by forming a barrier between the cold air above and the relatively warmer water below. 
• As the amount of sea ice decreases, the Arctic region’s cooling effect is reduced, and this may initiate a ‘feedback loop’ whereby ocean warming caused by more absorption of solar energy leads to an even greater loss of sea ice and further warming.”

Influence global climate:

• The massive sheets of ice that pad the Arctic region play a major role in influencing global climate and the rise and fall in Arctic sea temperatures.
•  During winter, the sea ice envelops most of the Arctic Ocean and in summer, a portion of it melts due to being exposed to longer periods of sunlight and elevated temperatures. 
• Sea ice normally melts and is at its thinnest and most sparse in mid-September, when the area covered by ice is roughly half the size of the winter maximum. 
• With the onset of winter and dipping temperatures, the ice begins to expand and thicken, all the way until March when it reaches its zenith.

Wider impacts:

• Changes in sea ice can affect biodiversity and impact mammals such as polar bears and walruses, which rely on the presence of sea ice for hunting, breeding, and migrating. 
• The reduction in ice cover also affects the traditional subsistence hunting lifestyle of indigenous Arctic populations such as the Yup’ik, Iñupiat, and Inuit, the EPA notes. 
• On the other hand, reduced ice can present “commercial and economic opportunities” with the opening up of shipping lanes and increased access to natural resources in the Arctic region. 
• This has already provoked global competition with several countries, including India, vying for greater influence in groups such as the Arctic Council that governs access to Arctic resources.

Way ahead:

• The Arctic sea ice is decreasing is well-known and acknowledged in several reports of the Intergovernmental Panel on Climate Change (IPCC) and it is widely expected that the world will see its first ‘sea-ice free summer’ before 2050. 
• This, however, is under the assumption that global emissions will drive temperatures to beyond 4.5°C making the Arctic ice-free by 2081-2100. 
• The diminished sea ice while warming the Arctic also leads to a weakening of the polar jet streams, which are currents of air that form when warm and cold air meet. 
• This weakening has been linked to rising temperatures and heatwaves in Europe as well as unseasonal showers in northwest India. 
• While the ice-free summer may be inevitable, reducing carbon emissions might mean being better able to adapt to climate ‘tipping points.’