Global Glacier Melting Triggers 2 cm Sea Level Rise, Posing Severe Coastal Flood Risks
(Source – Indian Express, Section – Explained – Page No. – 14)
| Topic: GS3 – Environment – Climate Change |
| Context |
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Analysis of the news: 
Extent of Glacier Melting and Sea Level Rise
- Glaciers have been losing an alarming 273 billion tonnes of ice annually for the last 25 years.
- While 2 cm might seem negligible, experts warn that each centimetre of sea-level rise exposes an additional 2 million people to annual flooding, emphasizing the severe human impact.
Key Drivers of Sea Level Rise
1. Glacier and Ice Sheet Melting
- Global warming has accelerated the melting of glaciers and ice sheets, with glaciers losing between 2% and 39% of their ice regionally and 5% globally since 2000.
- This loss surpasses that of the Greenland and Antarctic ice sheets by 18%, posing a critical threat to coastal populations.
2. Thermal Expansion of Seawater
- As ocean temperatures rise, seawater expands—a phenomenon known as thermal expansion—responsible for one-third to half of the global sea level rise, according to NASA.
- This thermal expansion, coupled with ice melt, exacerbates sea level increases.
Sea Level Rise Trends and Regional Variations
- Since 1880, global sea levels have risen by 21 cm, with a sharp acceleration noted in recent decades—from 18 cm per year (1993) to 0.42 cm per year (2024).
- The rise is uneven globally; for example, the southwestern Indian Ocean sees a rise of 5 mm per year, surpassing the global average.
- In India, coastal cities like Mumbai have experienced the highest sea level rise (44 cm between 1987 and 2021), making them highly vulnerable due to low elevation.
- Other affected cities include Haldia (2.726 cm), Visakhapatnam (2.381 cm), and Kochi (2.213 cm).
Why Rising Sea Levels Are Concerning
1. Increased Flooding and Coastal Erosion
- Rising seas result in frequent coastal flooding, intensifying coastal erosion and displacing coastal populations.
- For example, the West Bengal coast lost 99 sq km of land between 1990 and 2016, highlighting the dire consequences of unchecked sea level rise.
2. Threat to Coastal Ecosystems and Freshwater Supplies
- Storm surges become more intense with higher sea levels, affecting mangroves, coral reefs, and salt marshes.
- Additionally, saltwater intrusion threatens freshwater reserves, impacting agriculture and daily water consumption.
3. Population Vulnerability
- Approximately 29% of the global population lives within 50 km of the coast, and 15% within 10 km, making large populations vulnerable to flooding, displacement, and economic disruption.
The Way Forward:
If greenhouse gas emissions continue unchecked, NASA estimates an additional 20 cm rise in sea levels by 2050, potentially doubling flood frequencies globally. Addressing this crisis requires:
- Global emission reductions to slow glacier melting.
- Coastal resilience planning in vulnerable regions.
- International cooperation to mitigate displacement and economic loss.
Conclusion
- The accelerating rise in sea levels, driven by glacier melting and thermal expansion, poses a serious threat to coastal communities, ecosystems, and global economies.
- With cities like Mumbai already witnessing significant impacts, immediate climate action is critical to prevent further disasters and ensure a sustainable future.
| Practice Question: Discuss the major causes of global sea level rise and analyze its potential socio-economic and environmental impacts, with a special focus on vulnerable coastal regions in India. (150 Words /10 marks) |
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