These are the numbers. Weather-related disasters forced people to leave their homes nearly 30 million times in 2025, according to new data from the Internal Displacement Monitoring Centre (IDMC). This was 13 per cent above the ten-year average.
East Asia and the Pacific accounted for 59 per cent of the total, with a majority displaced by monsoons in November. Wildfires are becoming a significant driver, causing 694,000 people to flee, the second highest figure in the past decade.
The data is stark. And yet, it captures only part of the crisis.
The IDMC produces the most widely recognised figures on internal displacement, based on a range of different sources – from government figures to UN agency reports. And yet, its figures cannot capture everyone: there are those not counted because humanitarian services cannot reach them; those who move gradually as livelihoods collapse; those forced to cross international borders.
Taken separately, these numbers tell one story: disasters are a growing driver of movement. Conflict too is forcing people from their homes in huge numbers. In fact, conflict displacements increased by 60 per cent year on year, according to the IDMC. And as Dialogue Earth’s Leaving Home series has shown, a person’s reason for leaving can rarely be attributed to one cause alone.
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It’s difficult to untangle climate change from the systems it works within. You’re more likely to see people say [they are moving] because of poverty or economic reasons or war – things that feel a bit more tangible to us than climate change.
Fahmida Miah, programme manager, Climate Outreach
Around the world, people are not moving because of conflict or climate extremes in neat, separate categories. They move through systems in which war, weather, poverty, borders, livelihoods and political decisions collide.
Jan Egeland, secretary general of the Norwegian Refugee Council, said “countless families” were returning to destroyed homes or found they were unable to return at all. “Such displacement is a sign of a global collapse in prevention of conflict and the basic protection of civilians,” he said.
What is a climate migrant?
A person may be described as a climate migrant when they move because of environmental changes caused or exacerbated by climate change.
Often, there is a direct connection between environmental changes and the decision to leave home. A person whose home is destroyed by a wildfire is an example. Those living in rural areas, whose incomes are tied up in farming or fishing – activities that are strongly impacted by environmental changes – might also migrate, permanently or temporarily.
Or the connection could be less direct.
The fact that leaving home is rarely motivated by a single factor can make it difficult to identify climate migration. According to one study, some of the leading “macro” contributors to migration are politics, economic factors and the environment.
Migrants are influenced by several drivers when they decide to move and often find their places of refuge under similar strain.
As we saw in Kenya’s Kakuma camp, people who have fled war and insecurity find themselves combating flood, drought, heat, shrinking food support and restricted livelihoods. In Afghanistan, families forced back across the border returned not to stability, but to a country marked by conflict, poverty, earthquakes, floods, drought and the possibility of further displacement. And in Chile’s Valparaíso region, fire did not only destroy homes; it forced a community to confront whether staying itself had become a form of risk.
Fahmida Miah, a programme manager at Climate Outreach, an environmental NGO, highlighted the subtle difference between displacement and migration. “Displacement is much more extreme and sudden. You see an entire village swept away by floods,” she explained. “Other people might see that the area is changing over 10 years. And you start to plan in response to that.”
Alex de Sherbinin of the Columbia Climate School said: “You have forms of displacement, and then migration itself can be broken down into forced and voluntary. There is no binary.”
What the numbers show, and what they miss
There is little definitive data on climate migration, so there is no single authoritative number for climate migrants. The IDMC data released earlier this month recorded 29.9 million internal displacements by disasters last year. Over the past decade, people have left their homes some 294.6 million times because of disasters such as floods, earthquakes and fires.
The numbers that do exist do not capture the scale of the crisis. “We see climate change as a risk amplifier,” says IDMC’s Alice Baillat. “We know it can amplify the frequency and the intensity of weather-related hazards, but it doesn’t necessarily mean that every flood or storm is attributed to climate change,” she said.
The IDMC data also only takes into account internal displacement. While the majority of climate migration does happen within borders, the data does not reflect those who are forced to leave their own country. “We do not look at cross-border movement,” Baillat said. “Our figure, unfortunately, is an underestimate of the reality of population movement due to climate change.”
Further, it only refers to displacement caused by disasters. This means it misses migration driven by gradual changes to the environment caused by climate change. If farmland becomes less productive, for example, a family may decide to move.
Academics have made other attempts to model or predict migration patterns linked to climate change. The most significant research in this field is the Groundswell reports prepared by the World Bank. The first edition, published in 2018, predicted that without action up to 3 per cent of the population of Sub-Saharan Africa, South Asia and Latin America will need to move by 2050. The second revised the total figure in a worst-case scenario upwards from 143 million to 216 million.
But all these numbers grapple with a problem: people who are forced to leave home are unlikely to view themselves as “climate migrants”, particularly when environmental change is just one of the several factors that influence their decision. “It is rare you find someone who confidently calls themselves a climate refugee or climate migrant, because of the intersectionality of the issue,” Miah said.
What can we do?
There are very few easy answers.
Relocation before environmental conditions make an area unsafe, or “managed retreat”, is a promising solution, but there are several challenges in its application. A 2023 study found that relocation plans sometimes proved financially damaging to those affected, and that community-led plans usually had better outcomes than those led by government.
De Sherbinin also highlighted the risks of “trapped” populations, who are being adversely affected by climate change but are unable to move, often because of a lack of finances, or documents, or fear of a loss of identity.
A paper published in 2025 warned that while populations are increasingly vulnerable to climate change impacts, some “lack the agency to move out of harm’s way”. This “involuntary immobility” is insufficiently addressed in policy, it concludes. “A poor agriculturalist without a passport and frankly very little power in the world clearly has more constraints than someone with a PhD in a developed country,” De Sherbinin said.
Proposed solutions have included cash transfers or mobility grants for trapped communities or more investment in adaptations like flood defences or drought-resistant agriculture. Some groups are starting to propose a “right to stay” as part of legal frameworks, De Sherbinin said. “We know enough now to say the poor and the least politically connected tend to suffer the greatest consequences,” he added. “We need to do things to intervene and improve their ability to withstand these shocks in the future.”
Miah said: “It’s difficult to untangle climate change from the systems it works within. You’re more likely to see people say [they are moving] because of poverty or economic reasons or war – things that feel a bit more tangible to us than climate change. But if you take a few steps back that becomes ‘the increased floods impacted my livelihood.’”
This means climate migration policy cannot only be about predicting movement. It must be about what makes movement necessary; what protection people find, or do not find, after they move; and what would allow them to remain safely where they are.
This is where data fails to fully capture a human crisis. A person may leave because of war and then live with drought in refuge. A family may be returned across a border into a country already weakened by disaster and a community may stay and rebuild and yet know that the next season could undo everything. None of these experiences fits neatly inside one category.
Leaving Home has followed that unsettled space: not only the moment people depart, but the longer condition in which home becomes harder to rely on. As shelter, as memory, as livelihood, as promise. The question then, is not only when someone becomes a climate migrant. The question is what happens when home is no longer home.
This article was originally published on Dialogue Earth under a Creative Commons licence.
