Climate Change Factors Driving Human Displacement: From Rising Seas to Extreme Weather

Climate change is no longer a distant threat-it’s actively reshaping where and how people can live. From rising seas that swallow coastlines to droughts that turn farmland to dust, environmental shifts are forcing millions to abandon their homes. Understanding the specific factors behind climate-induced migration reveals why this humanitarian challenge will only intensify in the coming decades-and why urgent action is needed now.

Global warming: the engine driving displacement 🔗

Human activities have pushed global temperatures approximately 1°C above pre-industrial levels, and the warming trend shows no signs of slowing. According to the Intergovernmental Panel on Climate Change (IPCC), this warming is projected to reach 1.5°C between 2030 and 2052 if current rates continue. The consequences of this temperature rise will persist for centuries to millennia, fundamentally altering climate systems worldwide.

The year 2024 was the warmest on record, and its effects were immediately visible in climate systems. NASA’s analysis confirmed that global sea levels rose faster than anticipated, driven largely by thermal expansion as oceans absorbed unprecedented heat. Every fraction of additional warming amplifies risks. The IPCC has documented that each additional 0.1°C of warming produces measurable increases in the intensity and frequency of temperature extremes, precipitation events, and agricultural droughts.

These aren’t abstract statistics. They translate directly into uninhabitable regions, failed harvests, and communities with no choice but to move. The United Nations reports that in 2024, disasters triggered a record 45.8 million internal displacements, with 99.5% caused by weather-related hazards such as floods, storms, wildfires, and droughts.

Sea level rise: threatening coastal populations worldwide 🔗

Sea level rise represents one of the most visible and irreversible consequences of climate change. Since satellite monitoring began in 1993, global sea levels have risen approximately 10 centimeters (4 inches), and the rate of rise has more than doubled over this period. In 2024, NASA researchers recorded an unexpected acceleration, with seas rising at 0.23 inches per year-significantly above the projected 0.17 inches annually.

The shifting dynamics of sea level rise 🔗

Historically, melting ice sheets and glaciers accounted for roughly two-thirds of sea level rise, while thermal expansion (water expanding as it warms) contributed about one-third. In 2024, however, those proportions reversed. Thermal expansion drove two-thirds of the year’s sea level rise, a direct consequence of record ocean temperatures. As NASA researcher Josh Willis noted, the ocean continues to rise, and the rate is accelerating year after year.

The implications for coastal communities are severe. The U.S. National Oceanic and Atmospheric Administration (NOAA) warns that higher background water levels amplify storm surges, pushing deadly and destructive flooding farther inland than ever before. High-tide flooding-sometimes called nuisance flooding-has increased dramatically over the past 50 years, disrupting daily life and damaging infrastructure even without major storms.

Regional vulnerabilities 🔗

Low-lying coastal zones, Pacific Island nations, and delta regions face the highest risks. NASA data shows that Pacific Island nations will experience at least 15 centimeters of sea level rise in the next 30 years, and the frequency of high-tide flood days will increase tenfold by the 2050s. For countries like Tuvalu, Kiribati, and Fiji, this isn’t a future scenario-it’s an existential threat unfolding now.

The consequences extend beyond flooding. Saltwater intrusion contaminates freshwater supplies and agricultural land. Infrastructure damage compounds economic losses. Intensified cyclones and storm surges destroy homes and livelihoods, leaving communities with few options but to relocate.

Drought patterns and agricultural collapse 🔗

While rising seas threaten coastlines, expanding droughts devastate inland regions dependent on agriculture. Climate change is disrupting rainfall patterns across multiple continents, reducing crop yields, depleting water resources, and forcing farming communities to abandon lands their families have worked for generations.

The global scope of drought 🔗

The European Commission’s Joint Research Centre reports that severe drought conditions persist across parts of central, northwest, and northeast Africa, with temperatures expected to remain above average and conditions likely to worsen in coming months. The impact on agriculture is significant, with below-average production, reduced crop yields, and increased food insecurity affecting multiple regions.

Africa is particularly vulnerable. The continent is warming faster than the global average, reducing water availability and intensifying drought conditions. According to Welthungerhilfe, approximately 620 million people-over 45% of Africa’s total population-lived in drylands as of 2020. For communities dependent on rain-fed agriculture, climate change isn’t a future concern; it’s a current crisis threatening survival.

How drought drives migration 🔗

The relationship between drought and displacement operates through multiple pathways. When rains fail and crops wither, rural households face impossible choices. Research published in npj Climate Action documents how drought and insufficient rainfall in West African countries like Ghana, Senegal, and Burkina Faso have forced rural populations to migrate to urban areas. Similar patterns appear across the Middle East, where recent droughts have strained already scarce water resources and reduced wheat production, triggering migration to cities.

In Asia, recurring droughts threaten livelihoods and force households to decide whether to migrate or attempt adaptation under worsening conditions. Families in the Bolivian and Ecuadorian Andes, heavily dependent on agriculture, have been severely affected by drought, compelling them to relocate to other rural areas or neighboring cities.

The Migration Policy Institute notes that while neither food insecurity nor drought necessarily leads to mass displacement, migration becomes more common when people are less able to adapt locally. This is particularly true in agriculture-dependent, low-income, and politically unstable countries where infrastructure and support systems are limited.

The scale of climate displacement: current numbers and future projections 🔗

The human toll of climate-related displacement is staggering and growing. UNHCR estimates that by mid-2024, around 90 million of the world’s 123 million forcibly displaced people were living in countries with high-to-extreme exposure to climate-related hazards-an increase of approximately 5 million from the end of 2023.

The 2024 UNHCR climate report reveals that nearly half of all forcibly displaced people now face both conflict and serious climate hazards. Countries like Sudan, Syria, Haiti, the Democratic Republic of the Congo, Myanmar, Ethiopia, Yemen, and Somalia experience this dangerous intersection of crises.

World Bank projections 🔗

The World Bank’s Groundswell report projected that without urgent climate and development action, Sub-Saharan Africa, South Asia, and Latin America could see more than 140 million internal climate migrants by 2050. These are people forced to leave increasingly unviable areas due to water scarcity, crop failure, sea level rise, and storm surges.

An updated World Bank analysis expanded the scope to include additional regions-East Asia and the Pacific, North Africa, and Eastern Europe and Central Asia-providing a global estimate of up to 216 million internal climate migrants by 2050 across all six regions. Sub-Saharan Africa faces the largest burden, with projections of up to 85.7 million internal climate migrants by mid-century.

These estimates are likely conservative. They focus primarily on slow-onset climate impacts-gradual changes in water availability, crop productivity, and sea levels-rather than rapid-onset disasters like floods and hurricanes that cause immediate displacement. The actual numbers could be substantially higher.

Hotspots of out-migration 🔗

Climate migration hotspots are emerging as distinct spatial patterns. Areas affected by declining water availability, reduced crop yields, and coastal flooding are projected to see significant population outflows. In Bangladesh alone, projections suggest up to 19.9 million internal climate migrants by 2050-nearly half the projected total for all of South Asia.

The North African region faces particular pressure due to severe water scarcity and the impacts of sea level rise on densely populated coastal areas, including the Nile Delta. Models predict that between 28.3 and 71.1 million people will be forced to migrate within Africa by mid-century.

The intersection of climate and conflict 🔗

Climate change rarely operates in isolation. Its impacts compound existing vulnerabilities and can escalate tensions over scarce resources. UNHCR notes that climate impacts can trigger conflicts over vital resources like water, fuel, and arable land, threatening peaceful coexistence between displaced populations and host communities.

The case of Sudan illustrates this deadly intersection. Devastating conflict has forced millions to flee, including 700,000 who have crossed into Chad-a country that has hosted refugees for decades while itself being among the most climate-exposed nations on Earth. Those who remained in Sudan face additional displacement risks from severe flooding that has compounded the humanitarian crisis.

Similarly, in Myanmar, 72% of refugees have sought safety in Bangladesh, where extreme cyclones and flooding present ongoing threats. For the world’s most vulnerable people, climate change multiplies existing dangers rather than creating entirely new ones.

Why most climate migrants stay within borders 🔗

A critical but often overlooked fact is that the vast majority of climate-displaced people move within their own countries rather than crossing international borders. The term “climate refugee” does not exist in international law. UNHCR prefers the phrase “persons displaced in the context of disasters and climate change” to more accurately describe this population.

This internal displacement creates its own challenges. As the World Bank research team leader Kanta Kumari Rigaud has noted, without proper planning and support, people migrating from rural areas into cities could face new and more dangerous risks. Urban areas in developing countries often lack the infrastructure, housing, and services to absorb large influxes of climate migrants, potentially leading to increased tensions and conflict over scarce resources.

Can we reduce climate migration? 🔗

While the numbers appear overwhelming, research consistently shows that climate-induced migration is not inevitable at its projected scale. The World Bank estimates that with concerted action-including global efforts to reduce greenhouse gas emissions and robust development planning-the worst-case migration scenarios could be reduced by as much as 80%, or more than 100 million people.

Key strategies include cutting greenhouse gas emissions to slow climate impacts, transforming development planning to account for climate migration patterns, investing in climate-resilient agriculture and infrastructure, and improving early warning systems and disaster preparedness. For communities in vulnerable regions, these aren’t abstract policy recommendations-they represent the difference between remaining in ancestral homelands or becoming part of the world’s growing population of displaced people.

What do you think? As climate impacts accelerate, should wealthier nations bear greater responsibility for supporting communities facing climate displacement? And how can we balance immediate humanitarian needs with long-term climate adaptation investments?

References

1. https://www.nasa.gov/missions/jason-cs-sentinel-6/sentinel-6-michael-freilich/nasa-analysis-shows-unexpected-amount-of-sea-level-rise-in-2024/
2. https://www.ipcc.ch/sr15/chapter/spm/
3. https://www.un.org/en/climatechange/science/climate-issues/degrees-matter
4. https://www.jpl.nasa.gov/news/nasa-analysis-shows-unexpected-amount-of-sea-level-rise-in-2024/
5. https://www.climate.gov/news-features/understanding-climate/climate-change-global-sea-level
6. https://sealevel.nasa.gov/news/279/nasa-data-helps-international-community-prepare-for-sea-level-rise/
7. https://joint-research-centre.ec.europa.eu/jrc-news-and-updates/severe-drought-africa-persists-and-expected-worsen-2025-04-23_en
8. https://www.welthungerhilfe.org/global-food-journal/rubrics/climate-resources/climate-hunger-migration-a-vicious-circle-in-africa
9. https://www.nature.com/articles/s44168-024-00133-1
10. https://www.migrationpolicy.org/article/east-africa-drought-food-insecurity-refugees
11. https://www.unrefugees.org/news/how-climate-change-impacts-refugees-and-displaced-communities/
12. https://www.unhcr.org/publications/no-escape-frontlines-climate-change-conflict-and-forced-displacement
13. https://www.worldbank.org/en/news/press-release/2018/03/19/climate-change-could-force-over-140-million-to-migrate-within-countries-by-2050-world-bank-report
14. https://documents1.worldbank.org/curated/en/540941631203608570/pdf/Overview.pdf
15. https://www.unhcr.org/us/what-we-do/build-better-futures/climate-change-and-displacement