Sea Level Change

Published on 06 Apr 2025

The variations in the average level of the world's oceans over time are referred to as sea level change. According to WMO’s Report “Global Sea level rise and Implications” indicate that between 2013 and 2022, Global mean sea-level was 4.5 mm/year and human influence was likely the major driving force of these increases since at least 1971.

Causes of accelerated Sea Level Rise

• Global Warming: The main factor contributing to the acceleration of sea level rise is global warming, which is brought on by rising greenhouse gas concentrations.

• Melting Glaciers and Ice caps: Greenland and Antarctica contain giant ice sheets that are also considered glaciers. As temperatures rise, glaciers melt faster than they accumulate new snow.

• Example: Global warming has increased the speed at which glaciers in Greenland are melting by fivefold over the last 20 years, scientists from the University of Copenhagen

• Ocean warming: Oceans hold 90% of the excess heat produced by global warming due to greenhouse gas emissions which may result in thermal expansion of water.

• Example: The amount of heat stored in the upper 2,000 metres of the global ocean or the ocean heat content reached 286 ZJ in 2023 relative to the 1981–2010 average, according to a study published in Advances in Atmospheric Sciences.

• Earth's gravitational and rotational field: Sea level can also vary geographically due to variations in the Earth's rotational and gravitational fields.

• Anthropogenic Activities: The main causes of global warming and, consequently, the acceleration of sea level rise are human activities like the combustion of fossil fuels and deforestation.

• Example: Close to 20% of Goa’s shore along its 139-km-long coastline has been eroded due to sea level rise and human intervention such as deforestation and urbanization, according to MoES.

Impacts of Sea Level Change

• Increased flooding and erosion: Coastal regions with low lying areas will be more susceptible to erosion and floods, which could cause harm to infrastructure, natural ecosystems, and structures.

• Example: Climate change is expected to accelerate sea-level rise and coastal cities such as Shanghai are most at risk of increased flooding.

• Saltwater intrusion: A decrease in water quality can also result from saltwater seeping into freshwater habitats and aquifers due to rising sea levels.

• Example: Saltwater intrusion into Mississippi from Gulf of Mexico

• Increased frequency of cyclones: The likelihood of cyclones could rise as the Global Mean Sea Level and ocean temperatures continue to rise.

• Example: According to the IITM, the frequency, duration, and intensity of cyclones in the Arabian Sea have increased significantly due to increase in sea surface temperature.

• Loss of biodiversity and ecosystem services: Important coastal habitats like mangroves and salt marshes may disappear as a result of sea level rise.

• Displacement of coastal communities: Millions of people who live in low-lying coastal areas may have to move to safer areas due to sea level rising.

• Example: Displacement of El Bosque community in Tabasco, Mexico due to sea level rise

Government initiatives and policy measures

• National Centre for Sustainable Coastal Management: It is an autonomous institution to support the protection, conservation, rehabilitation, management, and policy advice of the coast.

• National Adaptation Fund for Climate Change (NAFCC): To meet the cost of adaptation to climate change for the State and Union Territories of India that are particularly vulnerable to the adverse effects of climate change.

• National Cyclone Risk Mitigation Project (NCRMP): It reduces reduce vulnerability to cyclone and other hydro-meteorological hazards of coastal communities in Project States and to increase the capacity of State entities to effectively plan for and respond to disasters.

International initiatives

• Paris Agreement: The goal is to hold the increase in the global average temperature to well below 2°C above pre-industrial levels” and pursue efforts “to limit the temperature increase to 1.5°C above pre-industrial levels.

• The Future Earth Coasts Program: To work to support sustainability and adaptation to global change in the coastal zone.

• United Nations Decade of Ocean Science for Sustainable Development (2021-2030): It seeks to stimulate ocean science and knowledge generation to reverse the decline of the state of the ocean system and catalyse new opportunities for sustainable development of this massive marine ecosystem.

Way Forward

• Reducing Greenhouse Gas Emissions: The adoption of sustainable behaviors, increased energy efficiency, and a shift to cleaner energy sources are critical components of climate change mitigation.

• Coastal Protection: To lessen the effects of storm surges and erosion, invest in coastal protection techniques including seawalls, levees, and mangrove restoration.

• Infrastructure Planning: Develop and implement adaptable infrastructure designs that account for sea level rise such as flood-resistant structures, elevating roads, and constructing buildings on stilts.

• Community Education: Increase community awareness and preparedness by spreading information on sea level rise, its effects, and adaptation strategies.

Tags:
Environment

Keywords:
Global warming Climate change Sea level Coastal area

Syllabus:
General Studies Paper 3

Topics:
Environment and Climate Change