The False Link Between Climate Change and Mass Migration
Here’s how it really works.
“The great climate migration has begun.” “Climate crisis could displace 1.2bn people by 2050.” “Migration will soon be the biggest climate challenge of our time.”
These are just some of the headlines that have appeared in major international newspapers. They reflect a widely shared belief that climate change will lead to mass migration. A broad coalition of journalists, politicians, climate activists and migration experts have claimed that the effects of global warming will lead to massive movements of climate refugees.
Much media attention has focused on the fate of “sinking islands” in the Pacific, such as the Maldives and Tuvalu, widely seen as the first victims of climate change. We are told that rising sea levels are forcing more and more people to relocate—the world’s first climate refugees. Experts have claimed that a series of devastating climate change-related hurricanes in Central America have spurred migration to the United States, and that protracted droughts are forcing more and more Africans onto boats in desperate attempts to reach Europe. From this viewpoint, countering climate change by reducing carbon emissions is the only way to prevent a human tide of climate refugees from overwhelming Western countries.
How it really works
Climate change is real. Since the start of the Industrial Revolution in the late nineteenth century, average global temperatures have risen by 1.1°C, and according to estimates by the Intergovernmental Panel on Climate Change (IPCC) they are likely to rise by a further 1.0–1.8°C in a very low greenhouse gas emissions scenario, 2.1–3.5°C in a moderate scenario, or as much as 3.3–5.7°C in an extreme scenario.
Because of the complexity of climate systems, we cannot predict exact impacts, but there is widespread consensus that global warming will lead to significant changes in climates around the world. While rainfall may increase in various polar, temperate and tropical zones, large parts of southern Africa, the Mediterranean, Latin America and Australia are likely to get dryer. Scientists also expect that climate change will increase the occurrence of extreme weather events such as hurricanes, droughts, floods and heatwaves. The melting of temperate glaciers and ice caps, as well as “thermal expansion” caused by higher water temperatures, will accelerate sea level rise.
Global warming is one of the most pressing issues facing humanity. However, to link this issue with the specter of mass migration is a dangerous and misleading practice based on myth rather than fact. The typical approach of apocalyptic climate migration forecasts has been to map changes induced by climate change (such as sea level rise, drought or desertification) onto settlement patterns to predict future human displacement. For instance, if climate change models predicted a sea level rise of (say) 50 centimeters, it would be possible to map all coastal areas affected by this and work out how many people lived in such areas. The assumption is that all these people would then have to move.
I have always been flabbergasted at how naively some serious research organizations buy into such deterministic reasoning, which assumes a one-on-one relation between the environment and migration, in which “environmental pressures” somehow automatically generate movement. There are many reasons to be wary of this narrative, but here are just three.
1. “The good land is there where the flood is”
Geographers have long observed that people show huge resilience in coping with scarcity and environmental threats. In fact, people have often moved towards, instead of away from, places with the greatest environmental hazards, such as river valleys and coastal areas, because these also tend to be the most fertile and prosperous areas—the exact opposite of the climate refugee forecasts.
The paradox is that the most fertile agricultural lands also tend to be most prone to flooding. For this reason, throughout history, people have settled in low-lying areas despite the risk of seasonal flooding and the usual inconveniences such as hot and sticky weather, mosquitoes and waterborne diseases such as malaria. The Limpopo valley in southern Mozambique is a fertile agricultural area that is subject to regular, sometimes disastrous flooding, which occasionally drives farmers from their fields and homes. However, few people bother moving out of the valley permanently, because that is where the water and fertile lands are. As local farmers would say, “The good land is there where the flood is.”
For this reason, people are not keen to abandon their lands in fertile river valleys and delta areas. They have historically learned to cope with seasonal and occasional flooding so it becomes a way of life—for instance, by building dykes, mounds, houses on stilts or even floating homes. In fact, fertile soils and abundant water are the very reasons that river plains and delta areas have always attracted people, have high population densities, and were the cradles of early states and civilizations.
2. Lands are rising as the seas are rising
Dramatic forecasts of massive climate migration are also based on the assumption that sea level rise will drive people out of coastal areas. However, we cannot just assume that low-lying areas will be submerged. This is mainly because processes of sedimentation—leading to land growth—can counterbalance the effects of erosion and sea level rise. Sediments are small parts of rocks, soil, dead plants and animals, such as shells and coral, which have been eroded by strong flows of water, glaciers and winds. Sediment is deposited on riverbeds, floodplains and seabeds, causing existing coastal lands to rise and new lands to form in the sea.
Land rise because of sedimentation explains why studies of satellite images have shown that most deltas, mangroves and other coastal marshlands in the world have actually grown, not shrunk over the past decades, despite the rise in sea level. While it is uncertain whether land gains will be able to keep up with accelerated sea level rise in the future, such evidence shows the naivety of the simplistic “lands will be flooded” narrative.
The evidence also counters the stereotype that the Pacific islands are massively “sinking” into the ocean. Again, this is because the effects of sea level rise and erosion are counterbalanced by the sedimentation of material generated by the surrounding reef, such as dead coral, weathered shells and dried-up microorganisms. One study that analyzed thirty Pacific and Indian Ocean atolls—comprising 709 islands in total—revealed that 89 per cent of islands were either stable or had grown in land area, while only 11 per cent had decreased in size. In Tuvalu, a small Pacific nation often singled out by the media as one of the first nations likely to disappear entirely due to sea level rise in the future, a recent study found that between 1971 and 2014, eight of Tuvalu’s nine atolls and almost three-quarters of the 101 reef islands had grown in size. This increased Tuvalu’s total land area by 3 per cent, even though in Tuvalu sea levels rose at twice the global average.
This undermines the entire assumption—and popular media narratives—that climate change-related sea level rise is already a significant driver of current migration in delta areas such as Bangladesh or the Pacific islands. This doesn’t mean there’s no possibility that future sea levels will outpace land gains through sedimentation. But we cannot just assume that land will simply be submerged because sea levels are rising. And it’s clearly nonsensical to link recent and current migrations to climate change-driven sea level rise.
3. Environmental hazards can trap poor people into immobility
Nor can we assume that environmental stresses in general will automatically “push” people out of their homes. A wide range of studies has shown that people generally prefer to stay home in the wake of natural shocks, and will do everything they can to stay put. In situations where agricultural productivity is affected, individual members of families with sufficient assets may migrate to towns or cities as a strategy to earn extra income. However, such moves are more likely to be internal and temporary than international and permanent, as people generally prefer to stay close to home and long-distance migration is expensive.
The idea that climate change will lead to mass migration is based on popular “push-pull” models that naively assume that migration is somehow a linear function of poverty, violence and other forms of human misery. However, migration requires considerable resources, particularly long-distance migration from rural areas to cities or abroad. Extreme poverty—whether caused by environmental stress or other factors—actually tends to deprive vulnerable people of the means to travel and migrate over large distances, and they might therefore find themselves trapped where they are, unable to flee.
Detailed studies fail to find a simple causal link between environmental stress (whether linked to climate change or not) and migration. A severe drought in rural Mali, for instance, was found to increase short-distance, temporary migration to nearby towns to supplement family income, but did not increase long-distance and international migration. In Malawi, droughts and floods have been shown to decrease out-migration from rural areas to cities. Similarly, droughts in Burkina Faso have been shown to reduce international moves to Côte d’Ivoire.
So, scarcity and poverty—whether linked to environmental or other factors—may actually prevent people from migrating, certainly over long distances. It is therefore not surprising that studies of global migration trends have failed to find any clear correlation between climatic factors and long-term trends of international migration. This evidence defies the simplistic assumption that climate change will automatically “push” people to migrate.
The fabrication of a migration threat
The acceleration of global warming will have severe effects on production and livelihoods and the overall stability of the planet’s ecosystems, which may reach a dangerous tipping point. Urgent action is needed to prevent irreparable damage.
However, apocalyptic forecasts of massive climate migration lack any empirical basis, and are based on faulty assumptions about the relationship between environmental change and migration.
To argue in favor of cutting carbon emissions by raising the specter of massive climate migration is therefore a typical case of being right for the wrong reason. It is intellectually dishonest and puts the credibility of organizations using this argument—as well as the broader case for climate change action—seriously at risk.
Most importantly, the adverse consequences of climate change will most severely affect the most vulnerable populations, who lack the means to move out and who are most likely to get trapped in life-threatening situations. Genuine concerns about climate change should focus not on migrants, then, but on those unable to move at all.
Hein de Haas is a sociologist and geographer. A founding member of the International Migration Institute (IMI) at the University of Oxford, he is currently professor of sociology at the University of Amsterdam
Excerpted from How Migration Really Works: The Facts About the Most Divisive Issue in Politics by Hein de Haas. Copyright © 2023. Available from Basic Books, an imprint of Hachette Book Group, Inc.
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