State of the Global Climate 2022: The threat of rising sea levels

Source: The post is based on the article “The threat of rising sea levels” published in The Hindu on 28th April 2023

What is the News?

The World Meteorological Organisation (WMO) has released a report titled ‘State of the Global Climate 2022’.

What does the report say about sea level rise?

The world’s sea level is rising at an unprecedented rate. The rate of global mean sea-level [GSML] rise has doubled between the first decade of the satellite record and the last.

For instance, the rate of sea-level rise was 2.27 mm/year in 1993-2002, it has increased to 4.62 mm/year in 2013-2022.

The report also says that the earth’s ice cover, known as the cryosphere has thinned. 

Note: The cryosphere includes the Arctic and Antarctic regions (called “sea ice”), glaciers, the ice sheets of Greenland and Antarctica (area of ice on land covering more than 50,000 km2), seasonal snow cover and permafrost (mass of land that remains below 0 degree Celsius for at least two straight years).

What causes accelerated sea-level rise?

The report points to the following factors as being responsible for a rising GSML:

-Ice loss from glaciers and ice sheets

-Ocean warming: As increasing concentrations of carbon dioxide and other greenhouse gases drive global warming, 90% of the ‘extra’ heat is stored in the oceans. This leads to ocean warming. And as the ocean heats up, it undergoes thermal expansion, which in turn leads to a rise in the GSML. 

-Changes in the storage of land water.

What problems will sea level rise cause?

Firstly, the rising sea level will cause changes in land cover. This means rising seas will swallow more of the land cover particularly in coastal areas. Due to this, the coastal communities will face an acute shortage of land for human use.

Secondly, weather formations such as cyclones are known to typically originate in the open seas. As the GSML continues to rise, along with a rise in ocean temperatures, the chances of cyclones could increase.

– This will affect coastal communities and leads to large economic liabilities for tropical countries such as India and South Africa, which have high population densities.

Thirdly, as the GSML continues to rise, more seawater could seep into the ground, leading to the groundwater — which is usually freshwater — turning more and more saline.

How will sea level rise affect societies?

Due to sea level rise, the coastal ecosystems could be “completely changed”.

For example, in the Sundarbans delta in West Bengal, the world’s largest mangrove area, rising sea levels and coastal erosion has left more islands submerged underwater and that, in turn, has forced members of local communities to migrate.

This endangered the socio-economic stability of these coastal communities. This in turn has led to increased child trafficking in the Sundarbans area.

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