Important Geophysical phenomena such as earthquakes, Tsunami, Volcanic activity, cyclone etc., geographical features and their location? changes in critical geographical features (including water?bodies and ice?caps) and in flora and fauna and the effects of such changes
General Studies 3
Conservation, Environmental pollution and degradation, environmental impact assessment.
Disaster and disaster management
Melting of Arctic and Antarctic ice caps
Arctic and Antarctic are important global regions critical for the existence of the humankind on earth. Antarctica as part of the global commons and Arctic with the rim countries have to protect and conserve the same to avoid large scale disasters the world can face.
In recent months, unprecedented rates of glacier melts have been reported both in the Antarctic and the Arctic.
“A massive crack in Antarctica’s fourth-biggest ice shelf has surged forward by at least 10 kilometres since early January,” said Nature magazine in a recent article. Glaciers cover the terrain in both these regions, which have the only permanent ice sheets that still exist on earth today.
Earth till now:
The earth has enjoyed a more or less stable temperature for the last 10,000 years.
Prior to that there were several ice ages and periods of warmer temperature, also known as inter-glacials.
The ice ages are believed to have been caused by small shifts in the earth’s orbit, but all the reasons for the temperature fluctuations observed are not yet entirely understood.
What could happen in the current century, as a result of anthropogenic climatic change, remains a matter of great interest within the scientific and policymaking community.
The melting Antarctic:
The Antarctic ice sheet is 14 million sq km in area and holds a large amount of frozen fresh water. (In comparison, the area of India’s land mass is about 3.1 million sq km.)
If all the ice over the Antarctic were to melt, sea levels would rise by about 60 metres.
Parts of the ice sheet also flow into the ocean and do so through ice shelves that protrude into the water.
Several media reports over the last few months have covered the expanding rift or crack along the Larsen C shelf in the Antarctic, which is expected to break off at any time.
Larsen A and B collapsed in 1995 and 2002 respectively. Normally, ice shelves lose mass by the breaking off, or calving, of some of the portions and also by melting.
Even though the Larsen C collapse by itself, since it is in the water, will not raise sea levels, it will hasten the melting of the glacier it is connected to.
Rising sea levels
In the Arctic, if all the ice in the Greenland ice sheet were to melt, it would raise global sea levels by about 7 metres (or 23 feet).
Experts have known that there are feedback mechanisms that speed up glacier melt; exactly what these processes are and the rate by which they accelerate the melting remains an area of research.
Soot and dust carried by air from various places, bacteria and algal pigments in the melt water, any other pigments in the glacier can all reduce the reflection of the sunlight, thus increasing the absorption of heat energy by the ice.
This consequently increases ice melt, which then absorbs more solar radiation, thus accelerating a feedback process.
The meltwater flows into deep shafts, or moulins, that then speed up the flow of the glacier.
Global response needed:
The global community is well aware that many large and densely populated cities are located along the coast and in low-lying deltas.
Protecting the coast is an expensive undertaking and even then dikes, sea walls and similar structures provide only partial protection, based on studies undertaken by the Dutch Delta Committee and others.
For India, the east coast, especially certain low-lying districts, are extremely vulnerable to intensive storms, which then lead to flooding, salt-water intrusion, and loss of land and livelihoods.
On the west coast, while there are generally fewer storms, the concern is coastal erosion and flooding from sea level rise.
The discussion regarding sea level rise and potential coastal impacts needs also to be understood not just as a coastal phenomenon, but also as an issue that ripples through the entire economy.
Flooding in Chennai two years back did not affect just the land, but went through the economy as a whole and Swiss Re, the reinsurance company, has estimated losses to the economy due to the floods to be $2.2 billion.
Remedial Actions needed:
Thus, enforcing the coastal regulation zone, protecting vulnerable districts and the most vulnerable communities which rely on ecosystems and the sea for their livelihoods are areas that need strengthening.
Regional agreements related to refugees from climate effects need to be initiated. As a country which has generally been open to refugees from Tibet, Nepal, Afghanistan, Bangladesh and Sri Lanka, initiating and taking forward the conversation on regional planning for extreme events such as sea level rise would be important for India, the largest country in the region.
India being a peninsular nation itself and any change in sea levels can affect livelihoods to a high extent. Further as a responsible nation in world comity India has to set the agenda for responsible action and timely remedial measures for the same.
Connecting the dots
Elaborate on the effect that seal level rise can have on coastal livelihoods and nation’s economy especially with recent reports on changes in the Arctic and Antarctic.