ARCTIC SEA ICE

1. Context

2. Why is the Arctic sea ice important?

• The massive sheets of ice that pad the Arctic region plays 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.

3. The United States Environment Protection Agency (EPA) explains the importance of sea ice

• Sea ice is light-colored, reflecting more sunlight 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.
• 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 Yup'ik, Inupiat, and Inuit.
• On the other hand, reduced ice can present commercial and economic opportunities by opening shipping lanes and increasing 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.

4. What does the new study say?

• The world will see its first 'sea-ice-free summer' before 2050.
• The global emissions will drive temperatures to beyond 4.5°C making the Arctic ice-free by 2081-2100.
• There is no scenario under which the Arctic sea ice can be saved in summer.
• Moreover, if drastic reductions in emissions are not undertaken, we could very well be seeing the first such summer in the 2030s.

5. What’s the basis for this study’s conclusions? 

• The researchers first estimated how much of the ice melting was due to human instigated, or anthropogenic factors and they found that this was as much as 90%, and the rest of it was caused by natural variability.
• They established that the climate models, which even the IPCC relied on, underestimated the rapidity of melting.
• When they corrected for this, it turned out that there were also likely to be ice-free Augusts and Octobers by 2080 in the emission scenarios where the temperature rose above 4.5°C. 

6. Consequences

• 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'.