Effect of global warming on Sea level rise
Recently Scientists found in a study that due to the effect of global warming, the sea level around ‘Lakshadweep Islands’ will rise. This rise in water level will affect airports and residential areas close to the coast.
It may be noted that Lakshadweep is the smallest union territory of India. There are 36 small islands in this archipelago; its area is 32 square km.
Rise in sea level:
- The effects of climate change have resulted in an increase in the water level of the world’s oceans, in particular ‘global warming’, driven by three primary factors: thermal expansion, glaciers, the melting of Greenland and Antarctica region ice.
- The sea level is measured mainly through tide stations and ‘satellite laser altimeters’.
Factors of sea level rise
- Thermal Expansion of Water: When water is heated, the water molecules expand i.e. water expands. About half of the sea level rise over the past 25 years is due to warmer oceans that take up more space.
- Melting of glaciers: Increase in temperature due to global warming, mountain glaciers melt more in summer. This creates an imbalance between runoff and ocean evaporation, which raises the sea level.
- Damage to Greenland and Antarctic ice plates: Due to increased temperature, the vast ice plates covering Greenland and Antarctica are melting at a more rapid rate, similar to mountain glaciers, increasing sea water even more rapidly.
Rate of rise in sea level:
- Globally: It should be noted that the global sea level has increased during the last century but in recent decades its rate of increase has seen intensification. Between 1880 and 2015, the average global sea level rose by 9 inches, much faster than the previous 2,700 years.
In 2019, a report titled ‘The Special Report on the Ocean and Cryosphere in a Changing Climate’ by the ‘Intergovernmental Panel on Climate Change’ (IPCC) outlined the serious changes in oceans, glaciers and land and sea ice deposits.
- Regional level: It is not uniform in all parts of the world. The rise in ‘regional sea level’ may be greater or less than global ‘water level rise’ due to subduction, erosion, regional ocean currents, upstream flood control, variations in land elevation and compressive weight of ice age glaciers.
Consequences of rise in sea level:
- Destruction of coastal area biodiversity: Sea level rise can cause catastrophic erosion, wetland flooding, aquifer and agricultural soil contamination with salt, and loss of biodiversity habitat.
- Increase in Dangerous Storms: Rising sea level is causing more dangerous storms causing more damage to life and property.
- Lateral and inland migration: ‘Floods’ in low-lying coastal areas are forcing people to migrate to higher land areas, creating a worldwide refugee displacement crisis.
- Impact on infrastructure: The potential for high coastal water levels also threatens access to the Internet and basic services such as food items.
- Threats to inland life: Rising sea levels can contaminate soil and groundwater with salt.
Steps taken to address sea level rise:
- Relocation: Many coastal urban areas are planning to adopt resettlement as a mitigation strategy. For example ‘Kiribati Island’ has planned to shift to ‘Fiji’, similarly ‘Indonesia’ is planning to shift its capital from ‘Jakarta’ to ‘Borneo’.
- Construction of sea wall: In the year 2014 Indonesia started a coastal development project called a giant sea wall or “Great Garuda”, this project will serve to protect the city from floods.
- Building Enclosure: Scientists have proposed the ‘Northern European Enclosure Dam’ (NEED), which includes all fifteen countries of the North Sea to protect them from rising seas. The Persian Gulf, the Mediterranean Sea, the Irish Sea, the Baltic Sea, and the Red Sea were also identified as areas that could receive protection from similar mega enclosures.
- Architecture for water flow management: The Dutch city of Rotterdam has also built drainage and innovative architectural features for obstacles such as “water squares” with temporary ponds.
- India has a coastline of 7,516 km, of which 5,422 km of coastline belongs to 9 states and 2,094 km of coastline includes islands of 4 union territories.
- The seaside trade accounts for 90 percent of the country’s total trade and is spread over 3,331 coastal villages and 1,382 islands.
National Action Plan on Climate Change: It was released in the year 2008 by the Prime Minister’s Council on Climate Change. Its main objective is to spread awareness among the representatives of the public, various agencies of the government, scientists, industry and communities about the threat posed by climate change and the steps to combat it.
Source – PIB