Concerns of Rising Sea Level (SLR)
Why in news?
World Meteorological Organization’s (WMO) State of the Global Climate 2022 report highlighted that the world’s sea level is rising at an unprecedented rate.
How much is the sea rising?
- The rate of global mean sea-level (GSML) rise has doubled between the first decade of the satellite record and the last.
- To calculate the rate of change in the GSML, e. how fast or slow the sea level is changing, we can calculate the difference in the GSML across a few years, usually a decade, and then divide the difference by the number of years.
- The sea level has been rising in the last 3 decades.
- The rate of sea-level rise was 27 mm/year in 1993-2002, it shot up to 4.62 mm/year in 2013-2022.
What causes accelerated sea-level rise (SLR)?
- Thermal expansion due to increasing ocean temperatures.
- Ocean warming the phenomenon of rising mean ocean temperatures contributed 55% to GSML rise.
- According to the State of the Global Climate 2022 report in 2005-2019, loss of glaciers and ice sheets contributed 36% to the GSML rise.
- Changes in the storage of land water contributed less than 10% to GSML
- Thinning of cryosphere leading to melting of glaciers.
- The cryosphere includes the Arctic and Antarctic regions, seasonal snow cover, and permafrost (mass of land that remains below 0º C for at least 2 straight years).
- Increasing concentrations of carbon dioxide and other greenhouse gases.
What are the impacts of sea level rise?
- Groundwater crisis – It allows the salt water to enter underground making the underground water salty.
- Coastal areas – It affects the coastal areas by swallowing the land.
- Migration – People in coastal areas gets migrated due to increasing sea level rise.
- Land cover – May be decreased leading to population density.
- Acute shortage of land for human use.
- Cyclones – The chances of cyclones could increase, affecting coastal communities and leading to large economic liabilities to tropical countries.
- Disintegrate the coastal communities – People on the coastal ecosystem may be affected and push them to poverty and force them to migrate.
Steps taken to Tackle SLR:
- Relocation: Many coastal cities have planned to adopt relocation as a mitigation strategy. For example, Kiribati Island has planned to shift to Fiji, while the Capital of Indonesia is being relocated from Jakarta to Borneo.
- Building Sea Wall: Indonesia’s government launched a coastal development project called a Giant Sea Wall or “Giant Garuda” in 2014 meant to protect the city from floods.
- Building Enclosures: Researchers have proposed Northern European Enclosure Dam (NEED), enclosing all of the North Sea to protect 15 Northern European countries from rising seas. The Persian Gulf, the Mediterranean Sea, the Baltic Sea, the Irish Sea, and the Red Sea were also identified as areas that could benefit from similar mega enclosures.
- Architecture to Steer Flow of Water: Dutch City Rotterdam built barriers, drainage, and innovative architectural features such as a “water square” with temporary ponds.
Vulnerability of India:
India’s 7,516-kilometre-long coastline includes 5,422 kilometres of coastline on the mainland and 2,094 kilometres on the islands belonging to nine states and four Union Territories.
The coastline accounts for 90% of the country’s trade and it spans 3,331 coastal villages and 1,382 islands.
Coastal Regulation Zone: The coastal areas of seas, bays, creeks, rivers, and backwaters which get influenced by tides up to 500 m from the high tide line (HTL) and the land between the low tide line (LTL) and the high tide line were declared as Coastal Regulation Zone (CRZ) in 1991.
The latest regulation also takes into account rising sea-levels due to global warming.
National Action Plan on Climate Change: It was launched in 2008 by the Prime Minister’s Council on Climate Change. It aims at creating awareness among the representatives of the public, different agencies of the government, scientists, industry and the communities on the threat posed by climate change and the steps to counter it.
The Paris Agreement provides a clear vision on limiting global warming and thus, SLR. Some of the other steps in this direction would include:
- Switching from fossil fuels to clean alternatives like solar and wind energy.
- Instituting carbon taxes on industries and subsidies for reducing the carbon footprint.
- Carbon sequestration by geo-engineering and natural methods like restoring peatland and wetland areas to capture existing greenhouse gases.
- Afforestation and reducing deforestation.
- Subsidizing research on climate change.