Greenland Ice sheet melted the most last year, in over fifty years according to a study by US scientists.
“The world continues to warm,” the National Oceanic and Atmospheric Administration said in a briefing paper for reporters. “Multiple indicators, same bottom-line conclusion: consistent and unmistakable signal from the top of the atmosphere to the bottom of the oceans.”
The Greenland Ice sheet is a large body of ice, in fact the largest in the Northern Hemisphere. It comes second to the largest body of ice- the Antarctic Ice sheet. If the Greenland Ice sheet melts completely, the sea level would rise by 7m.
The Oslo-based Arctic Monitoring and Assessment Program said in May that warming in the Arctic was on track to lift sea levels by up to 5.3 feet (1.6 meters) by 2100, a far steeper jump than predicted a few years ago.
The reducing Greenland Ice sheet is a cause for alarm as it will impact not just Greenland but the entire region and would also have far reaching impacts on a global scale. Arctic sea ice shrank to its third smallest area on record, while the world’s alpine glaciers shrank for the 20th straight year, the study said.
How did the Greenland Ice Sheet form?
Greenland is near the Arctic Circle, in fact above the Arctic Circle and so subject to extremely cold temperatures. It witnesses continuous periods of night for months and then continuous days, a feature common near the poles. For the ice sheet to accumulate, temperature must be below the freezing point. The successive layers of snow undergo compression from the layers above and become compact and solid. The ice sheet is most vulnerable near the margins and loses ice, large chunks of ice may break off and move into the sea forming what are known as icebergs.
According to the predictions of the IPCC (Intergovernmental Panel on Climate Change) by 2100, annual temperatures over the Arctic will be 3 to 8 0 C high that the 1951-1980 reference period. Such an increase in temperature will definitely lead to an increased rate of melting of Greenland ice sheet. For the Ice sheet to be stable and in equilibrium, it should add the same amount of ice that it loses, global warming has adversely affected this stability and it would lose ice at a greater rate than it manages to add.
How does Global Warming and increased temperatures adversely affect the Greenland Ice Sheet?
By reducing albedo (amount reflected to the incident solar radiation) because of the deposition of particles of dust and soot (black carbon) into the ice. Further, the increased temperatures favour the melting of ice in the form of icebergs. Till 1990, the ice sheet was still stable, i.e. the amount it lost was compensated by the amount added, however this shift was aggravated by global warming. However, the melting of ice is not the solitary factor that contributes to an increase in sea levels; it is also brought about by the thermal expansion of water.
Greenland Ice sheet melting would have far reaching effects such as-
- Increase in the sea level: The melting ice sheet is already leading to an increase in the sea levels. This poses a major threat to the small island states if the sea levels continue to rise.
- Oceanic Circulation: This is perhaps the single most damage that global warming can cause. The ocean currents play a major role in shaping the earth’s climate, the water is cooled in the arctic regions and it sinks comprising the cold water currents that moves towards the south. A disruption of this heat carrying oceanic cycle could lead to much cooler climates elsewhere.
Apart from this, the everlasting impact this melting will necessarily have on populations living in and around Greenland remains to be seen. The increased melting contributes to release of water which reduces the salinity and density of surface water near the coasts. This affects the production capacity of the oceans. These abrupt changes are bound to affect the food chains, marine life, and productive capacity of the oceans ultimately disrupting the marine ecosystems as a whole.
Reference and further Reading- Snow, Water, Ice and Permafrost in the Arctic (SWIPA), 2009.
Article by Mr. Puskar Pande