SEA-LEVEL rise is among the most ominous of multifaceted risks attributed to climate change, and has serious implications for billions of people. Rising sea levels are one of the primary indicators of global warming, originating in the early 20th century, when fossil fuels consumed by the expanding industrial complex released huge amounts of greenhouse gas (GHG) emissions. While extreme weather events induced by climate change cause huge damage during short spells, the long-term risks associated with sea-level rise are equally lethal and pose serious threats to life.

Sea levels rise in two ways: through melting glaciers and ice sheets releasing more water, and through thermal expansion due to an increase in global temperatures. The year 2023 was confirmed as the hottest year on record by a clear margin, and this year, many parts of the world have experienced record-breaking heatwaves. According to the World Meteorological Organisation’s (WMO) State of Global Climate report, “In 2023, global mean sea level reached a record high in the satellite record (since 1993), reflecting continued ocean warming (thermal expansion) as well as the melting of glaciers and ice sheets”.

Its impact on coastline communities is deeply disturbing as it degrades ecosystems, reduces habituality and increases exposure to ocean hazards, according to UNEP’s Global Foresight Report, 2024. Almost 40 per cent of the global population live within 100 kilometres of the sea. Some of the more populous urban centres in developing countries located close to the coast are at risk: Mumbai, Bangkok, Shanghai, and Karachi in Asia, Lagos in Africa, and Buenos Aires in Latin America.

Most at risk, however, are people living in low-elevation coastal areas. In some of the Pacific Islands nations, where the sea level is rising faster than elsewhere, residents are forced to relocate to other areas in search of livelihoods. This trend could spread to other low-lying areas and see a spike in numbers of dislocated persons in the coming years. According to the World Bank, sea-level rise could displace over 216 million people by 2050 worldwide, mostly in low-lying regions and coastal cities.

UN Secretary General António Guterres rightly says that “rising seas are sinking futures”. As sea levels creep up, coastal erosion worsens, while saltwater intrusion reduces food productivity, resulting in the loss of habitat for plants, fish and other freshwater marine life. However, the ramifications of sea-level rise are not limited to inflicting damage in just these areas. It goes beyond, into the remit of international law, carrying human rights implications, particularly in low elevation coastal regions where a small rise of a few centimetres can lead to land loss of several kilometres, displacing communities and degrading the economic and social well-being of its inhabitants.

As sea levels creep up, coastal erosion worsens.

Shrinking land masses can raise questions about the limits of exclusive economic zones, continental shelves and demarcation of maritime boundaries between states. Also pertinent would be the determination of the national status of people, for example, in a small island nation, who run the risk of dislocation to another country due to loss of habituality in their own countries. What will be the national and legal status of such dislocated people in their new abodes when their lands are swallowed by the sea?

These issues have been taken up at UN fora in recent years. An open-ended Study Group of the International Law Commission is deliberating on the topic ‘Sea-level rise in relation to international law’. Scientific data produced by the WMO, the IPCC, UNEP and others have helped a better understanding of the risks associated with ocean swelling and how to tackle it.

On the policy side, the UN General Assembly, through two resolutions on oceans and law of the sea, has called for action to address the sea-level rise, among other measures, by urgent climate action and enhancing the capacity of developing countries for adaptation and resilience to environmental disasters. The Security Council met to specially discuss this subject last year.

This month, a high-level meeting convened by the president of the UN General Assembly at the UN in New York will seek to strengthen international and multisectoral cooperation for “addressing the threats posed by sea-level rise”.

Urgently reducing GHG emissions — the primary driver of climate change — is key to controlling sea-level rise. Developing countries will need to integrate sea-level rise into climate risk assessments and prioritise ecosystem-based adaptation and nature-based solutions, such as protecting and expanding mangrove coverage, to buffer against the threats posed by sea-level rise to their peoples and economies.

The writer is director of intergovernmental affairs, United Nations Environment Programme.

Published in Dawn, September 21st, 2024