RESEARCH STARTER

Islands and sea-level rise

Islands, particularly small and low-lying ones, are increasingly threatened by sea-level rise due to global warming. This phenomenon is primarily caused by thermal expansion of seawater and the melting of polar ice sheets and glaciers. As sea levels rise, many islands face ecological degradation, submersion, and severe erosion, which poses risks to human, animal, and plant life. Saltwater intrusion compromises freshwater supplies, making drinking water scarce and threatening agricultural productivity. With a significant number of small islands located just a few feet above sea level, their inhabitants face dire consequences, including the potential for becoming climate refugees. Historical examples include the evacuation of the Carteret Islands in Papua New Guinea and the disappearance of Lohachara Island. Despite contributing minimally to greenhouse gas emissions, island nations experience the brunt of climate change effects, evoking discussions on social and environmental justice. Global collaborations among island nations aim to address these challenges and advocate for their rights and needs in the face of an uncertain future.

Full Article

Global warming causes thermal expansion and ice melt, increasing seawater volume and provoking more frequent and severe storms. As a result, small, low-lying islands are threatened with ecological degradation and submergence.

Background

Global warming threatens the survival of low-lying islands, deltas, and beaches. In 2010, the National Research Council, as reported by the US Environmental Protection Agency (EPA), estimated that by the year 2100, sea levels will have risen between 16 and 56 inches (40.64 and 142.24 centimeters) since 1990. Subsequent assessments have refined these projections. The Intergovernmental Panel on Climate Change reported in the early 2020s that global mean sea level is likely to rise between approximately 11 and 40 inches (28 to 101 centimeters) by 2100, depending on future greenhouse-gas emissions scenarios. Even under lower-emissions pathways, continued sea-level rise poses significant risks to low-lying islands, coastal deltas, and beaches, threatening ecosystems, freshwater supplies, and human settlements. Rising sea levels threaten human, animal, and plant life, as arable land and potable water are compromised. Refugee migrations and species extinctions result.

Conditions

For millennia before the nineteenth century, Earth’s sea levels remained relatively stable. However, as the pace of industrialization and urbanization accelerated around the globe, sea levels began to rise by millimeters per year. Tide gauges and satellite monitoring indicate that this rise has increased in recent decades. Two factors contribute to increases in sea volume. One is thermal expansion, which causes warming waters to increase in volume. The other is the melting of ice sheets and glaciers at the North and South Poles and in the mountains of the Andes, Alps, and Himalayas. Observational records compiled since the early twenty-first century show that global mean sea level rise accelerated from roughly 0.06 inches per year (about 1.5 millimeters per year) during much of the twentieth century to more than 0.12 inches per year (over 3 millimeters per year) by the 2010s and 2020s.

Retreating ice has been noted in all these regions over the late twentieth and early twenty-first centuries. Ice melt in Greenland begins earlier each summer, leaving ever-smaller areas to refreeze by winter. The runoff water from the melt penetrates glaciers, loosening their attachment to rock surfaces. Large chunks then break away, in a process known as “calving,” launching masses of ice several square kilometers in area that float away, eventually melting in warmer waters. The snow and ice of ski fields in Switzerland have disappeared, as the snow line rises in altitude. Less snow and ice on the surface of the Earth reduces the deflection of sunlight, or albedo, thereby causing more warming in a positive feedback loop. Furthermore, thawing allows the escape of methane gases that have been locked in the frozen Earth, further strengthening the greenhouse effect. Satellite observations and field measurements collected since the 1990s, with increasing spatial and temporal resolution through the 2010s and 2020s, confirm that these processes are occurring across polar and high-mountain regions worldwide. Recent studies further indicate that permafrost thaw and associated methane release represent long-term climatic feedbacks that may persist for decades to centuries, even if global temperature increases are partially moderated.

Consequences

Islands are bodies of land surrounded by water, ranging in size from continents to tiny atolls. They can be found on all continents, oceans, and seas. One type of island rises from an underwater oceanic volcano, as the tip emerges above the water surface to form the island. The other type is an elevation of land on a continental shelf that rises above surrounding waters. Hawaii is an example of the former; the British Isles are instances of the latter. The smaller and closer an island is to sea-level elevations, the more vulnerable it is to rising sea levels. In addition to threats from rising sea levels, small islands are endangered by tropical storms, including hurricanes and cyclones. If the frequency and ferocity of these storms increase, the risk to islands does as well.

The consequences of this vulnerability are devastating in several respects. In addition to being submerged, small land bodies are being eaten away at their edges by erosion. Moreover, as salt water penetrates an island, salinity enters the water table below the island’s surface. The more salinity that freshwater absorbs, the less potable it is for drinking. Moreover, brackish water stunts or kills crops, reducing the food supply. The sustenance of not only humans but also wildlife is threatened.

Some islands are being abandoned by their inhabitants as the sea consumes the land. In 2009, facing predictions that their home would be completely submerged by 2015, the two thousand inhabitants of the Carteret Islands of Papua New Guinea began a community-wide evacuation effort that placed them among the world's first official climate-change refugees. Lohachara Island in the Bay of Bengal disappeared underwater in 2006; its residents fled to the mainland. Tuvalu, with a population under ten thousand, is a country of nine narrow coral atolls in the South Pacific. In 2024, NASA issued a dire warning for the Pacific Island nations of Tuvalu, Kiribati, and the Fiji Islands that they would receive at least 6 inches (15 centimeters) of sea level rise in the next thirty years even if greenhouse gas emissions are reduced. These islands, along with the Maldives and the Marshall Islands, are coral atolls with only a few feet of elevation, which puts people at risk because they cannot flee to a higher elevation. In 2014, for the first time, a Tuvaluan family was granted New Zealand residency based on their status as environmental refugees.

Many more environmental refugees followed suit. According to United Nations reporting, climate vulnerability increasingly overlaps with patterns of forced displacement. A UN report published in the early 2020s noted that roughly 75 percent of the more than 120 million forcibly displaced people worldwide lived in countries heavily affected by climate change. Related UNHCR-based analyses indicate that approximately 84 percent of refugees and asylum seekers in 2022 originated from highly climate-vulnerable countries, up from about 61 percent in 2010. By the end of 2023, additional reporting suggested that more than 70 percent of refugees and asylum seekers continued to come from countries classified as highly vulnerable to climate change, emphasizing a persistent and growing association between displacement and environmental stress.

By the early 2020s, scientists reported that global climate change had begun to rapidly reshape many islands worldwide. Assessments indicated that numerous island nations were likely to experience substantially increased flooding over the coming decades, with significant consequences for infrastructure, freshwater resources, and human habitation. While researchers emphasized that some impacts were already unavoidable due to past emissions, they also noted that the severity and pace of future environmental change would depend on mitigation efforts and adaptation strategies.

Prevention

Small island countries produce negligible amounts of greenhouse gases (GHGs), but they suffer most directly and critically the consequences of global warming caused by the major emitters. Small island countries act cooperatively through a number of organizations. The Global Islands Network (GIN) is an information clearinghouse and resources cooperative for islands all over the world. Complementing it is the Small Islands Development Network (SIDSnet), specializing in communications and information technology to support island maintenance and development. Members of the Alliance of Small Island States (AOSIS) coordinate their efforts through their respective UN diplomatic missions. The International Small Islands Studies Association (ISISA) is a professional organization that supports research about small islands. The International Scientific Council for Island Development (INSULA) supports the economic, technical, ecological, social, and cultural programs of the world’s islands and publishes INSULA: International Journal of Island Affairs, which specializes in nissology. Another periodical is the Island Studies Journal.

Since the early twenty-first century, small island states have increasingly focused their cooperative efforts on climate adaptation, disaster resilience, and access to international climate finance. Through forums such as the United Nations Framework Convention on Climate Change (UNFCCC), members of the Alliance of Small Island States have played a prominent role in advocating for emissions reductions, adaptation funding, and recognition of loss and damage associated with sea-level rise and extreme weather.

Context

Small, low-lying islands are idyllic yet fragile fragments of the Earth’s surface. Somewhat like a canary in a coal mine, their extinction is an early warning sign of ecological danger. Before they submerge, erosion and saltwater intrusion render them uninhabitable. Larger low-lying surfaces, such as delta regions and beaches, are also threatened. As more islands lose the means to sustain their populations, the number of environmental refugees in the world increases, putting further pressure on the planet’s remaining resources.

Small island populations account for a small share of global greenhouse gas emissions while experiencing early and pronounced effects of climate change. This asymmetry has become a subject of analysis in discussions of climate risk and international policy. Climate systems include reinforcing feedback processes, whereby initial warming can intensify conditions that contribute to additional warming. For populations living on low-lying islands and coastal areas, environmental change has increasingly affected long-term planning related to land use, infrastructure, and habitability.

Key Concepts

  • atoll: an island or islet consisting of a lagoon enclosed wholly or partly by a coral reef
  • brackish water: mixture of freshwater and seawater
  • calving: separation of a large portion of ice from a glacier or ice shelf, creating an iceberg
  • methane: a gas whose greenhouse effect is considerably stronger than that of carbon dioxide
  • nissology: the study of islands
  • thermal expansion: a heat-induced increase in the volume of a liquid or gas

Bibliography

Adamson, Joni, et al., editors. The Environmental Justice Reader: Politics, Poetics, and Pedagogy. U of Arizona P, 2002.

"Climate Change and Disaster Displacement." United Nations High Commission for Refugees (UNHCR), www.unhcr.org/us/what-we-do/build-better-futures/environment-disasters-and-climate-change/climate-change-and. Accessed 10 Dec. 2024.

"Climate Change 2021: The Physical Science Basis." IPCC, 2021, www.ipcc.ch/report/ar6/wg1/

Diamond, Jared M. Collapse: How Societies Choose to Fail or Succeed. Rev. ed., Penguin, 2011.

"Future of Climate Change." US Environmental Protection Agency, 12 Aug. 2025, www.epa.gov/climatechange-science/future-climate-change. Accessed 29 Jan. 2026.

Gerdes, Louise I., editor. Endangered Oceans: Opposing Viewpoints. Greenhaven, 2004.

Lisagor, Kimberly, and Heather Hansen. Disappearing Destinations: 37 Places in Peril and What Can Be Done to Help Save Them. Vintage, 2008. Print.

Maas, Amy. "Tuvalu Climate Change Family Win NZ Residency Appeal." New Zealand Herald. APN New Zealand, 2 Aug. 2014, www.nzherald.co.nz/nz/tuvalu-climate-change-family-win-nz-residency-appeal/JMA2SVA2HUB67XTUEXPJXN5DOA/. Accessed 29 Jan. 2026.

"NASA Analysis Shows Irreversible Sea Level Rise for Pacific Islands." NASA, 25 Sept. 2024, www.jpl.nasa.gov/news/nasa-analysis-shows-irreversible-sea-level-rise-for-pacific-islands/. Accessed 10 Dec. 2024.

Sundaresan, J., et al., editors. Climate Change and Island and Coastal Vulnerability. Springer, 2013.

Tompkins, Emma L., et al. Surviving Climate Change in Small Islands: A Guidebook. Tyndall Center for Climate Change Research, 2005.

"UNHCR Report Finds 90 Million Displaced People Face Climate Hazards." United Nations High Commisioner for Refugees, Development Aid, 11 Nov. 2025, www.developmentaid.org/news-stream/post/201852/unhcr-climate-change-displaced-people-90-million-conflict-report. Accessed 29 Jan. 2026.

"UNHCR Report Reveals Climate Change Is a Growing Threat to People Already Fleeing War." UNHCR, 12 Nov. 2024, www.unhcr.org/us/news/press-releases/unhcr-report-reveals-climate-change-growing-threat-people-already-fleeing-war. Accessed 29 Jan. 2026.

Full Article

Global warming causes thermal expansion and ice melt, increasing seawater volume and provoking more frequent and severe storms. As a result, small, low-lying islands are threatened with ecological degradation and submergence.

Background

Global warming threatens the survival of low-lying islands, deltas, and beaches. In 2010, the National Research Council, as reported by the US Environmental Protection Agency (EPA), estimated that by the year 2100, sea levels will have risen between 16 and 56 inches (40.64 and 142.24 centimeters) since 1990. Subsequent assessments have refined these projections. The Intergovernmental Panel on Climate Change reported in the early 2020s that global mean sea level is likely to rise between approximately 11 and 40 inches (28 to 101 centimeters) by 2100, depending on future greenhouse-gas emissions scenarios. Even under lower-emissions pathways, continued sea-level rise poses significant risks to low-lying islands, coastal deltas, and beaches, threatening ecosystems, freshwater supplies, and human settlements. Rising sea levels threaten human, animal, and plant life, as arable land and potable water are compromised. Refugee migrations and species extinctions result.

Conditions

For millennia before the nineteenth century, Earth’s sea levels remained relatively stable. However, as the pace of industrialization and urbanization accelerated around the globe, sea levels began to rise by millimeters per year. Tide gauges and satellite monitoring indicate that this rise has increased in recent decades. Two factors contribute to increases in sea volume. One is thermal expansion, which causes warming waters to increase in volume. The other is the melting of ice sheets and glaciers at the North and South Poles and in the mountains of the Andes, Alps, and Himalayas. Observational records compiled since the early twenty-first century show that global mean sea level rise accelerated from roughly 0.06 inches per year (about 1.5 millimeters per year) during much of the twentieth century to more than 0.12 inches per year (over 3 millimeters per year) by the 2010s and 2020s.

Retreating ice has been noted in all these regions over the late twentieth and early twenty-first centuries. Ice melt in Greenland begins earlier each summer, leaving ever-smaller areas to refreeze by winter. The runoff water from the melt penetrates glaciers, loosening their attachment to rock surfaces. Large chunks then break away, in a process known as “calving,” launching masses of ice several square kilometers in area that float away, eventually melting in warmer waters. The snow and ice of ski fields in Switzerland have disappeared, as the snow line rises in altitude. Less snow and ice on the surface of the Earth reduces the deflection of sunlight, or albedo, thereby causing more warming in a positive feedback loop. Furthermore, thawing allows the escape of methane gases that have been locked in the frozen Earth, further strengthening the greenhouse effect. Satellite observations and field measurements collected since the 1990s, with increasing spatial and temporal resolution through the 2010s and 2020s, confirm that these processes are occurring across polar and high-mountain regions worldwide. Recent studies further indicate that permafrost thaw and associated methane release represent long-term climatic feedbacks that may persist for decades to centuries, even if global temperature increases are partially moderated.

Consequences

Islands are bodies of land surrounded by water, ranging in size from continents to tiny atolls. They can be found on all continents, oceans, and seas. One type of island rises from an underwater oceanic volcano, as the tip emerges above the water surface to form the island. The other type is an elevation of land on a continental shelf that rises above surrounding waters. Hawaii is an example of the former; the British Isles are instances of the latter. The smaller and closer an island is to sea-level elevations, the more vulnerable it is to rising sea levels. In addition to threats from rising sea levels, small islands are endangered by tropical storms, including hurricanes and cyclones. If the frequency and ferocity of these storms increase, the risk to islands does as well.

The consequences of this vulnerability are devastating in several respects. In addition to being submerged, small land bodies are being eaten away at their edges by erosion. Moreover, as salt water penetrates an island, salinity enters the water table below the island’s surface. The more salinity that freshwater absorbs, the less potable it is for drinking. Moreover, brackish water stunts or kills crops, reducing the food supply. The sustenance of not only humans but also wildlife is threatened.

Some islands are being abandoned by their inhabitants as the sea consumes the land. In 2009, facing predictions that their home would be completely submerged by 2015, the two thousand inhabitants of the Carteret Islands of Papua New Guinea began a community-wide evacuation effort that placed them among the world's first official climate-change refugees. Lohachara Island in the Bay of Bengal disappeared underwater in 2006; its residents fled to the mainland. Tuvalu, with a population under ten thousand, is a country of nine narrow coral atolls in the South Pacific. In 2024, NASA issued a dire warning for the Pacific Island nations of Tuvalu, Kiribati, and the Fiji Islands that they would receive at least 6 inches (15 centimeters) of sea level rise in the next thirty years even if greenhouse gas emissions are reduced. These islands, along with the Maldives and the Marshall Islands, are coral atolls with only a few feet of elevation, which puts people at risk because they cannot flee to a higher elevation. In 2014, for the first time, a Tuvaluan family was granted New Zealand residency based on their status as environmental refugees.

Many more environmental refugees followed suit. According to United Nations reporting, climate vulnerability increasingly overlaps with patterns of forced displacement. A UN report published in the early 2020s noted that roughly 75 percent of the more than 120 million forcibly displaced people worldwide lived in countries heavily affected by climate change. Related UNHCR-based analyses indicate that approximately 84 percent of refugees and asylum seekers in 2022 originated from highly climate-vulnerable countries, up from about 61 percent in 2010. By the end of 2023, additional reporting suggested that more than 70 percent of refugees and asylum seekers continued to come from countries classified as highly vulnerable to climate change, emphasizing a persistent and growing association between displacement and environmental stress.

By the early 2020s, scientists reported that global climate change had begun to rapidly reshape many islands worldwide. Assessments indicated that numerous island nations were likely to experience substantially increased flooding over the coming decades, with significant consequences for infrastructure, freshwater resources, and human habitation. While researchers emphasized that some impacts were already unavoidable due to past emissions, they also noted that the severity and pace of future environmental change would depend on mitigation efforts and adaptation strategies.

Prevention

Small island countries produce negligible amounts of greenhouse gases (GHGs), but they suffer most directly and critically the consequences of global warming caused by the major emitters. Small island countries act cooperatively through a number of organizations. The Global Islands Network (GIN) is an information clearinghouse and resources cooperative for islands all over the world. Complementing it is the Small Islands Development Network (SIDSnet), specializing in communications and information technology to support island maintenance and development. Members of the Alliance of Small Island States (AOSIS) coordinate their efforts through their respective UN diplomatic missions. The International Small Islands Studies Association (ISISA) is a professional organization that supports research about small islands. The International Scientific Council for Island Development (INSULA) supports the economic, technical, ecological, social, and cultural programs of the world’s islands and publishes INSULA: International Journal of Island Affairs, which specializes in nissology. Another periodical is the Island Studies Journal.

Since the early twenty-first century, small island states have increasingly focused their cooperative efforts on climate adaptation, disaster resilience, and access to international climate finance. Through forums such as the United Nations Framework Convention on Climate Change (UNFCCC), members of the Alliance of Small Island States have played a prominent role in advocating for emissions reductions, adaptation funding, and recognition of loss and damage associated with sea-level rise and extreme weather.

Context

Small, low-lying islands are idyllic yet fragile fragments of the Earth’s surface. Somewhat like a canary in a coal mine, their extinction is an early warning sign of ecological danger. Before they submerge, erosion and saltwater intrusion render them uninhabitable. Larger low-lying surfaces, such as delta regions and beaches, are also threatened. As more islands lose the means to sustain their populations, the number of environmental refugees in the world increases, putting further pressure on the planet’s remaining resources.

Small island populations account for a small share of global greenhouse gas emissions while experiencing early and pronounced effects of climate change. This asymmetry has become a subject of analysis in discussions of climate risk and international policy. Climate systems include reinforcing feedback processes, whereby initial warming can intensify conditions that contribute to additional warming. For populations living on low-lying islands and coastal areas, environmental change has increasingly affected long-term planning related to land use, infrastructure, and habitability.

Key Concepts

  • atoll: an island or islet consisting of a lagoon enclosed wholly or partly by a coral reef
  • brackish water: mixture of freshwater and seawater
  • calving: separation of a large portion of ice from a glacier or ice shelf, creating an iceberg
  • methane: a gas whose greenhouse effect is considerably stronger than that of carbon dioxide
  • nissology: the study of islands
  • thermal expansion: a heat-induced increase in the volume of a liquid or gas

Bibliography

Adamson, Joni, et al., editors. The Environmental Justice Reader: Politics, Poetics, and Pedagogy. U of Arizona P, 2002.

"Climate Change and Disaster Displacement." United Nations High Commission for Refugees (UNHCR), www.unhcr.org/us/what-we-do/build-better-futures/environment-disasters-and-climate-change/climate-change-and. Accessed 10 Dec. 2024.

"Climate Change 2021: The Physical Science Basis." IPCC, 2021, www.ipcc.ch/report/ar6/wg1/

Diamond, Jared M. Collapse: How Societies Choose to Fail or Succeed. Rev. ed., Penguin, 2011.

"Future of Climate Change." US Environmental Protection Agency, 12 Aug. 2025, www.epa.gov/climatechange-science/future-climate-change. Accessed 29 Jan. 2026.

Gerdes, Louise I., editor. Endangered Oceans: Opposing Viewpoints. Greenhaven, 2004.

Lisagor, Kimberly, and Heather Hansen. Disappearing Destinations: 37 Places in Peril and What Can Be Done to Help Save Them. Vintage, 2008. Print.

Maas, Amy. "Tuvalu Climate Change Family Win NZ Residency Appeal." New Zealand Herald. APN New Zealand, 2 Aug. 2014, www.nzherald.co.nz/nz/tuvalu-climate-change-family-win-nz-residency-appeal/JMA2SVA2HUB67XTUEXPJXN5DOA/. Accessed 29 Jan. 2026.

"NASA Analysis Shows Irreversible Sea Level Rise for Pacific Islands." NASA, 25 Sept. 2024, www.jpl.nasa.gov/news/nasa-analysis-shows-irreversible-sea-level-rise-for-pacific-islands/. Accessed 10 Dec. 2024.

Sundaresan, J., et al., editors. Climate Change and Island and Coastal Vulnerability. Springer, 2013.

Tompkins, Emma L., et al. Surviving Climate Change in Small Islands: A Guidebook. Tyndall Center for Climate Change Research, 2005.

"UNHCR Report Finds 90 Million Displaced People Face Climate Hazards." United Nations High Commisioner for Refugees, Development Aid, 11 Nov. 2025, www.developmentaid.org/news-stream/post/201852/unhcr-climate-change-displaced-people-90-million-conflict-report. Accessed 29 Jan. 2026.

"UNHCR Report Reveals Climate Change Is a Growing Threat to People Already Fleeing War." UNHCR, 12 Nov. 2024, www.unhcr.org/us/news/press-releases/unhcr-report-reveals-climate-change-growing-threat-people-already-fleeing-war. Accessed 29 Jan. 2026.

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