Context: A newly published study highlights that melting ice from glaciers worldwide has led to the sea level rising by almost 2 cm this century alone.
Relevance of the Topic: Prelims: Key trends regarding climate change.
Major Highlights of the Study
- Study: Community estimate of global glacier mass changes from 2000 to 2023.
- Contributors: Scientists from the University of Edinburgh (Scotland) and the University of Zurich (Switzerland)
Findings:
- Melting ice has led to the sea level rising by almost 2 cm this century alone.
- Glaciers have been losing 273 billion tonnes of ice each year, equivalent to water Earth’s entire population would consume over a period of 30 years.
Glacial Melting and Sea Rise
- According to the US agency National Oceanic and Atmospheric Administration (NOAA):
- The rate of glacial melting has doubled from 0.18 cm per year in 1993 to the current rate of 0.42 cm per year.
- The global sea level has risen by about 21-25 cm since 1880.
- As per the National Aeronautics and Space Administration (NASA), global sea levels have risen by more than 10 cm between 1993-2024.
- According to a World Meteorological Organisation report, sea level is not rising uniformly around the world (owing to local changes in ocean heat content and salinity). For example- the southwestern Indian Ocean region is seeing sea level rise at a rate of 2.5 mm per year, faster than the global average.
Indian Scenario
Data from the Center for Study of Science, Technology and Policy (CSTEP), Bengaluru.
- Mumbai has witnessed a rise of 4.44 cm between 1987 and 2021, the worst among Indian cities.
- West Bengal’s Haldia has witnessed a sea-level rise of 2.726 cm.
- Andhra Pradesh’s Visakhapatnam has witnessed a sea-level rise of 2.381 cm.
- Kerala’s Kochi has witnessed a sea-level rise of 2.213 cm.
Factors contributing to the Sea level Rise:
Sea level rise is essentially the increase in the average height of the ocean’s surface, measured from the centre of the Earth.
- Global Warming: This has resulted in increased melting of land-based ice, such as glaciers and ice sheets. According to the latest study, since 2000, glaciers have lost between 2% and 39% of their ice regionally, and about 5% globally.
- Thermal expansion of seawater: With global temperatures rising, oceans are becoming warmer, and as a result, the volume of water is increasing as well. According to the National Aeronautics and Space Administration (NASA) thermal expansion of seawater is responsible for one-third to half of global sea level rise.
Concerns associated with the rising sea levels
As per the study “Every centimeter of sea level rise exposes another 2 million people to annual flooding somewhere on our planet”.
- Flooding and erosion of coastal areas:
- Sea level rise leads to more frequent and intense coastal flooding, which exacerbates coastal erosion.
- According to a 2018 report by the National Centre for Coastal Research (NCCR), between 1990 and 2016, the West Bengal coast alone lost almost 99 sq km of land.
- More severe geophysical phenomenon:
- The rise results in more intense storm surges, allowing more water inland during tropical storms.
- This in turn can impact coastal ecosystems like mangroves, coral reefs and salt marshes, contaminate fresh water supplies etc.
- Displacement of population:
- Submergence, erosion and intense climatic events may result in huge displacement of coastal populations, which in turn would adversely impact their livelihood and their age-old traditions.
- A 2024 study in the journal Scientific Reports found that 15% of the global; population lived merely 10 km away from water.
- Changes in weather patterns: Addition of a considerable amount of freshwater into the ocean is concerning as this increase in freshwater has the potential to disturb the oceanic circulations, which is a crucial system of ocean currents responsible for shaping the Earth's climate and weather patterns.