Global Sea Level Rise

Recent studies highlight the alarming rise in global sea levels, primarily driven by climate change. Research indicates that glaciers have been losing 273 billion tonnes of ice annually, contributing to a sea level rise of nearly 2 cm this century. This seemingly minor increase carries implications for millions worldwide. The paper titled ‘Community estimate of global glacier mass changes from 2000 to 2023’ reveals critical vital information about the ongoing crisis.

About Sea Level Rise

Sea level rise refers to the increase in the average height of the ocean’s surface. Two main factors contribute to this phenomenon. First, the melting of glaciers and ice sheets is a major cause. Glaciers have lost 2% to 39% of their ice since 2000, with a global loss of about 5%. Second, thermal expansion of seawater occurs as global temperatures rise. This phenomenon accounts for one-third to half of the current sea level rise.

Current Statistics

Since 1880, global sea levels have risen approximately 21 cm. However, the rate of increase has accelerated in recent years. From 1993 to 2024, the rate jumped from 0.18 cm per year to 0.42 cm per year. This acceleration is unprecedented in over 2,500 years. Notably, the rise is not uniform across the globe. For example, the southwestern Indian Ocean is experiencing a rise of 2.5 mm per year, exceeding the global average.

Regional Impacts

Coastal cities are particularly vulnerable to rising sea levels. In India, cities like Mumbai have seen a rise of 4.44 cm from 1987 to 2021. Other cities such as Visakhapatnam and Kochi also report increases. These changes threaten the livelihoods of millions living in low-lying coastal areas.

Consequences of Rising Sea Levels

The impacts of rising sea levels are deep. Increased flooding leads to coastal erosion and displaces populations. Between 1990 and 2016, West Bengal lost nearly 99 sq km of land due to rising sea levels. Additionally, storm surges during tropical storms become more intense, further threatening coastal ecosystems. Freshwater supplies may also become contaminated, affecting daily life for many.

Future Projections

If greenhouse gas emissions remain unchecked, sea levels could rise by an additional 20 cm by 2050. This would double the changes observed in the past century. Such projections indicate a future with more frequent and severe flooding events globally.

Global Response and Mitigation

Addressing sea level rise requires concerted global efforts to reduce greenhouse gas emissions. Climate policies must adapt to protect vulnerable coastal communities and ecosystems. Research and technological advancements play vital roles in understanding and mitigating these impacts.

Questions for UPSC:

1. Critically discuss the factors contributing to global sea level rise and their implications on coastal ecosystems.
2. Examine the relationship between climate change and the frequency of extreme weather events in coastal regions.
3. Estimate the potential impact of rising sea levels on the socioeconomic conditions of coastal populations globally.
4. Point out the measures that can be implemented to mitigate the effects of sea level rise on urban coastal areas.

Answer Hints:

1. Critically discuss the factors contributing to global sea level rise and their implications on coastal ecosystems.

1. Melting glaciers and ice sheets account for sea level rise, with glaciers losing 273 billion tonnes of ice annually.
2. Thermal expansion of seawater contributes one-third to half of the current sea level rise due to increasing ocean temperatures.
3. Regional variations exist, with some areas experiencing faster rises, affecting local ecosystems differently.
4. Coastal ecosystems like mangroves and coral reefs are threatened by increased flooding and erosion, impacting biodiversity.
5. Displacement of coastal communities leads to loss of habitat and resources, further stressing ecosystems and human systems.

2. Examine the relationship between climate change and the frequency of extreme weather events in coastal regions.

1. Climate change increases ocean temperatures, leading to more intense storms and hurricanes.
2. Higher sea levels amplify storm surges, resulting in greater flooding during extreme weather events.
3. Changes in precipitation patterns can lead to both droughts and floods, impacting coastal communities.
4. Extreme weather events are becoming more frequent, with studies indicating a direct correlation with rising global temperatures.
5. Coastal infrastructure is increasingly at risk, necessitating improved resilience and adaptation strategies.

3. Estimate the potential impact of rising sea levels on the socioeconomic conditions of coastal populations globally.

1. Sea level rise threatens livelihoods, particularly in fishing and agriculture, which are vital for coastal economies.
2. Displacement due to flooding can lead to increased poverty and loss of property among coastal populations.
3. Infrastructure damage from rising seas can strain local economies and increase government expenditures on disaster response.
4. Access to clean water may be compromised due to saltwater intrusion, affecting health and sanitation.
5. Social inequalities may worsen as vulnerable populations are disproportionately affected by rising sea levels.

4. Point out the measures that can be implemented to mitigate the effects of sea level rise on urban coastal areas.

1. Implementing coastal defenses like seawalls and levees can help protect urban areas from flooding.
2. Restoration of natural barriers such as mangroves and wetlands can absorb storm surges and reduce erosion.
3. Urban planning should incorporate climate resilience strategies, including zoning laws that restrict development in high-risk areas.
4. Investment in infrastructure improvements, such as drainage systems, can help manage increased rainfall and flooding.
5. Community education and engagement are essential for developing local strategies to adapt to changing conditions.