Syllabus :GS 3/Environment
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NASA reported that global sea levels rose faster than expected in 2024, reaching 0.59 cm per year, surpassing the anticipated 0.43 cm.
Global Mean Sea Level
- Global mean sea level provides an integrative measure of the state of the climate system, encompassing both the ocean and cryosphere (ice covered portions of Earth).
- It is the average height of the entire ocean surface.
- It is a key indicator of climate change, reflecting changes in both the ocean and ice-covered regions.
Causes of Global Mean Sea Level changes
- Ice Melt: Warming causes ice sheets and glaciers to melt, adding freshwater to the ocean.
- Thermal Expansion: As oceans absorb heat, water expands, raising sea levels.
- In 2024, thermal expansion contributed to two-thirds of the rise, a shift from previous years when melting ice was the dominant factor.
- It was also the warmest year on record, with Earth’s oceans at their highest levels in three decades. Since 1993, global sea levels have risen by 10 cm, with the rate of rise more than doubling.
- Land Water Storage: Changes in water storage on land, such as groundwater pumping or dam building, can alter the amount of water in the ocean.
- Climate change is the primary driver of global sea level rise.
Effects of Global Sea Level Rise
- Threatens infrastructure, including roads, bridges, and buildings, leading to increased repair costs.
- Causes more frequent and severe coastal flooding, exacerbating erosion and saltwater intrusion into freshwater supplies.
- Endangers coastal ecosystems (e.g., mangroves, coral reefs) and displaces people in low-lying areas, causing social and economic challenges.
- Economic and Social Impacts: Rising seas lead to higher costs for coastal protection (e.g., sea walls) and infrastructure repairs.
- Displacement of communities and loss of livelihoods (tourism, fishing, agriculture) due to coastal flooding and erosion.
- Disrupts economic activities and places strain on social services, especially in vulnerable regions.
Countries Most Affected by Rising Sea Levels:
- High-Risk Countries: Bangladesh, China, India, and the Netherlands are highly vulnerable.
- Pacific Island Nations: Kiribati, Tuvalu, and the Marshall Islands face extreme risks due to high exposure to storms and sea-level sensitivity.
What can be done to counter sea level rise?
- Reduce Greenhouse Gas Emissions: The most important action is to slow global warming by cutting emissions, the primary cause of climate change and sea level rise.
- Mitigation and Adaptation: Build infrastructure like sea walls and storm surge barriers to protect against flooding and erosion.
- Improve drainage systems and construct flood-resistant buildings.
- Restore natural barriers like mangroves, wetlands, and coral reefs to absorb wave energy and reduce storm surge impacts.
- Disaster Risk Reduction: Strengthen disaster risk reduction plans and enhance early warning systems, supported by the UN, to address sea level-related incidents.
- In some cases, relocate communities from vulnerable coastal areas as part of adaptation strategies.
Source :TH
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