Global exodus: How climate change is forcing hundreds of millions of people to relocate

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The world’s first

In early December 2025, a passenger plane landed at Brisbane Airport on Australia’s east coast carrying three residents of the neighboring state of Tuvalu — a pastor, a truck driver, and a dentist, who had received Pacific Engagement Visas granting them the right to work, and to receive education and social protection. They were the first officially recognized climate migrants in history.

With a total population of 11,000, Tuvalu is one of the world's smallest and most vulnerable states, occupying a handful of low-lying coral atolls. More than a third of its residents applied for Australian relocation visas, and for very compelling reasons. With its average altitude of only a few meters above sea level, the country is already facing tangible consequences as a result of global climate change: flooding, salinization of soil and freshwater, coastal erosion, and damage to infrastructure.

Between 60% and 80% of the country’s population will be living in flood-prone areas by 2050, with projections for the end of the 21st century dependent on future emissions levels. The worst-case scenario shows sea levels rising by two meters — meaning most of the islands would be submerged, while the remaining land would face flooding for 100 days a year.

In November 2023, Australia and Tuvalu signed the bilateral Falepili Union agreement — the first international document to explicitly recognize climate change as sufficient grounds for migration and to establish an institutional mechanism for carrying out relocations. The arrangement is based on the concept of Falepili — a Pacific tradition of neighborliness, care, and mutual respect.

However, the relocation wave will be strictly limited. Under the agreement, up to 280 Tuvaluan citizens will be able to receive visas and move to Australia each year on a competitive basis. The Tuvaluan government aims to avoid a sharp population decline or a “brain drain.” The island nation intends to preserve its culture and political agency even in the face of climate threats through “mobility with dignity,” not flight.

What is climate migration? What makes it confusing?

The case of Tuvalu's first relocants marks the emergence of a new approach to climate migration, one that is so far limited to a single bilateral agreement between two countries. The international legal framework has no widely recognized official status for people forced to move due to climate change, and existing mechanisms for migrants and refugees address fundamentally different circumstances.

The international debate on climate migration gained serious momentum after the case of Ioane Teitiota, a citizen of Kiribati. In 2010, Teitiota sought asylum and recognition as a climate refugee in New Zealand, citing the threat of rising sea levels and deteriorating living conditions on his home islands. The court denied his claim, noting that international law does not recognize climate change as sufficient grounds for receiving refugee status — the 1951 UN Convention is focused on protecting people fleeing war and persecution.

In 2020, the UN Human Rights Committee did not consider the denial a violation of international law, since Teitiota’s life was not in imminent danger. However, it highlighted a crucial argument: returning people to countries where climate change endangers their lives can be regarded as a human rights violation. This marked the first instance of climate being recognized as a factor requiring political and legal consideration.

The controversy in the debate on climate migration is largely the result of the complex nature of the phenomenon. Droughts, floods, crop failures, and housing destruction all affected human mobility long before the era of global warming, and it is still impossible to make a clear distinction between “ordinary” natural disasters and events that can be definitively linked to climate change. Humanity is not dealing with entirely new threats; rather, we are faced with an increased frequency and intensity of already known risks, with their combination and impacts varying significantly across regions.

The main challenge to would-be “climate refugees” lies in the fact that climate change is rarely the sole reason for relocation — even if, according to research by the International Organization for Migration (IOM), the deterioration of living conditions linked to climate change is often what pushes people to move to new locations.

In this context, the issue of climate inequality becomes increasingly prominent. Not everyone has the means to adapt to new conditions — to reinforce infrastructure, insure homes, or relocate to safer areas — which is why Australian authorities, when presenting their agreement with Tuvalu, emphasized the idea that developed countries bear a special responsibility to assist those facing the consequences of global warming.

For now, the international debate largely revolves around definitions: who should be considered a climate migrant, how to identify them, and whether a separate term like “climate refugee” is even necessary given that climate is not the sole driver of migration. International organizations, such as the Intergovernmental Panel on Climate Change (IPCC), the IOM, and the UN, view such movement primarily as a form of forced mobility (which can be temporary or permanent, internal or cross-border).

Even in the absence of a universal definition, analytical documents are largely guided by a simple logic: environmental degradation undermines living conditions, a person loses their livelihood, and as a result, decides to relocate. The agreement between Australia and Tuvalu does not solve these problems, but for the first time, someone is at least offering an institutional response in the absence of common rules.

Climate migrants who wish to move abroad face the biggest obstacles, which is why most choose to relocate within their own countries. The barriers are not only legal — such as immigration status, visas, and rights — but also social and cultural. People tend to move to places where their language, social ties, and at least a partial sense of belonging are preserved.

When global warming overlaps with political and economic turbulence, this combination can escalate existing conflicts, as evidenced by the case of Syria, where the prolonged drought of 2007–2010 led to large-scale internal migration from rural areas to cities — about 1.5 million people became climate migrants inside the country. Although the drought was not a direct cause of the civil war, it intensified social pressure and vulnerability, becoming part of a more complex chain of events. As a result, over 6 million people were forcibly displaced within the country, and 5.5 million (as of 2020) fled to other states.

This example shows that climate migration depends, among other things, on the political context, the quality of governance, and a society’s capacity to adapt to change.

The most vulnerable

All sorts of geographical areas are vulnerable to climate change. Low-lying islands, mainly in the Pacific and Indian Oceans (such as Tuvalu, Kiribati, the Marshall Islands, and the Maldives), face a direct threat from rising sea levels, and even a small rise leads to flooding and storm surges, coastal erosion, soil and groundwater salinization, loss of freshwater, and noticeable inundation of land.

Coastal regions, including densely populated deltas of major rivers (such as the Ganges and Brahmaputra deltas in Bangladesh, the Nile in Egypt, the Mekong in Vietnam, and the Mississippi in the U.S.), suffer from flooding and salinization of water and soil. In Bangladesh, more than one-seventh of the country’s territory could be lost to the sea by 2050, and millions of people are already relocating each year due to natural disasters.

Arid regions are affected by increasingly frequent droughts and desertification. This primarily concerns the semi-deserts and dry steppes of the Sahel in North Africa, Central and South Asia, the Middle East, and southern Australia. Shortages of freshwater and declining crop yields are forcing rural communities to migrate to cities and neighboring countries.

Climate change has increased the risk of extreme water shortages in the Horn of Africa by roughly a hundredfold. A series of record-breaking droughts in Somalia over the past 15 years has triggered multi-million migrations and even resulted in loss of life. In 2010–2011 alone, deaths from disaster-related impacts in the country reached 258,000, with more than half of them children under five. At the moment, the country is under a state of emergency again, and the UN warns that there is a high risk of another humanitarian catastrophe. As a result, between 20 and 25 million people living in Somalia, Ethiopia, and Kenya are at risk of acute water and food shortages.

Mountainous areas are affected by glacier melting and changing precipitation patterns, leading to water shortages, loss of pastures, and increased risks of mudflows and landslides. One of the most vulnerable regions in this regard is Central Asia, where as many as 200–300 glaciers disappear annually, locals report the drying up of water sources, and experts warn of an imminent rise in forced migration — both into cities and across state borders. According to World Bank projections, the number of climate migrants in the region will be 2.4 to 3.4 million by 2050, depending on the pace of global warming.

Meanwhile, the Arctic is warming three to four times as fast as the rest of the world. Thawing permafrost negatively impacts traditional winter livelihoods and causes the ground beneath buildings and infrastructure to lose stability. In Alaska, more than 140 Indigenous communities are at risk, with some villages already relocating, and over the past 25 years, the Russian Arctic has lost about 20% of its population. Researchers note that climate is becoming an increasingly important factor in this process.

Even beyond these “hot seats,” the number and intensity of extreme natural events are increasing almost everywhere. The types of natural disasters vary by region, with some areas regularly flooded or hit by powerful tropical cyclones and hurricanes, while others face extreme droughts and intensifying heat waves.

Breaking the pattern: first-world climate migration

Even in developed countries, residents are beginning to lose faith in their own invulnerability. A striking example is California, where wildfires and prolonged droughts are increasingly “pushing” residents to other regions. After the Camp Fire in 2018, about 50,000 people who lost their homes left the state, and in 2025, more than 150,000 Californian residents were evacuated due to severe wildfires. Some will likely never return, thus becoming climate migrants.

In Australia, following the catastrophic floods and the Black Summer bushfires of 2019–2020, many families are relocating from particularly vulnerable areas. A 2024 demographic study showed that an average of 22,000 Australians change their place of residence each year due to major natural disasters (fires, floods, tropical cyclones).

European countries still have no data on large-scale climate-related displacement. However, southern countries such as Italy, Spain, and Greece have observed an increased frequency of wildfires, droughts, and floods, recording an alarming number of cases of forced migration as a result.

Even wealthy countries cannot shrug off climate problems, as a high income does not provide a lifetime guarantee against the loss of homes, infrastructure, or a familiar lifestyle. People can be forced from their homes not only by hunger or war, but also by the disappearance of reliable water sources, a surge in the number of extreme heat days, and recurring floods. Housing can lose its market value, and insurance companies may refuse to renew contracts.

Main trends and scale

The majority of people facing climate risks migrate domestically. According to IOM estimates, more than 218 million people have relocated inside different countries worldwide over the past decade. Most of them moved from rural and coastal areas to cities and industrial centers.

The IOM and World Bank emphasize that in countries of the so-called Global South, climate migration mainly follows the familiar “rural-to-urban” pattern. People are attracted to areas with higher incomes, well-developed infrastructure, and better access to education and healthcare. At the same time, triggers for relocation include crop loss, destruction of housing, and the increasing frequency of extreme events.

A well-studied example of this process is Bangladesh. Research shows that most of its internal migration occurs from low-lying coastal areas to cities: Dhaka, Chittagong, Khulna, and others. According to some estimates, up to 400,000 new migrants arrive in Dhaka each year (other studies put the figure at twice that number).

Surveys in urban slums, where many relocants end up, show that up to 70% of residents moved to the city following natural disasters or prolonged environmental stress caused by floods, sea-level rise, and tropical storms.

The scale of international migration driven by climate factors is not as large, but it is precisely this type that most often becomes the subject of political debate, media coverage, and legal discussion. People from countries where these risks are particularly high often move to more prosperous and less vulnerable regions, but they usually follow “well-trodden paths,” relocating for work or family reasons.

Forecasts

Predictions regarding the global scale of future climate migration vary due to the fact that it remains unknowable how well the world will limit global warming and how capably states will adapt to its effects. Current projection models bring together climatic, economic, and demographic variables, allowing for a wide range of estimates.

IPCC, World Bank, and IOM documents emphasize that international climate migration is particularly difficult to quantify. As long as climate change is not officially recognized as an independent and sufficient reason for relocation, even climate-motivated cross-border movements almost always end up being categorized as being motivated by economic or familial concerns.

As a result, the climate factor becomes “diluted” within overall migration statistics, making it significantly more difficult both to assess current international climate migration and to build accurate projections. Nevertheless, the IPCC notes that environmental factors could displace tens of millions of people by mid-century.

The situation is somewhat different for internal climate migration. More data are available for it, as such movements are more frequently recorded in national statistics and studies, making them easier to attribute. According to World Bank estimates, under the most pessimistic scenario, by 2050 up to 216 million people across a range of regions (South, East, and Central Asia; the Pacific region; Sub-Saharan Africa; Eastern Europe; and Latin America) could become internal migrants, relocating domestically due to sea-level rise, droughts, declining crop yields, and water scarcity. However, World Bank experts believe that with effective adaptation measures, these flows could be reduced by roughly 80%, meaning the migration effects of climate change will function as a test of our collective ability to respond to the challenges of the 21st century.