The UK has announced much harsher rules for asylum seekers, including more deportations for failed applicants. The US is massively expanding enforcement and detention capacity. The EU is doubling its border budgets. These moves come as ecological changes threaten to displace hundreds of millions of people in coming decades.
We face two broad choices. Wealthier, high-emitting countries can share resources and fund large-scale adaptation where it’s needed. Or they can protect access to livable land and resources by building physical and regulatory barriers, enforced through expanded policing and deportation. Recent policy trends suggest many governments are choosing the latter.
Climate pressures are already making parts of the world hard to inhabit. A 2020 Institute for Economics and Peace report estimated 2.6 billion people face high or extreme water stress today, rising to 5.4 billion by 2040. Droughts, heatwaves, floods, cyclones, failing harvests and related conflicts will drive mass displacement. The IEP warned up to 1.2 billion people might be displaced by 2050; the World Bank gives a more cautious number of around 216 million people displaced within their own countries by mid-century.
Most movement will be internal, but internal displacement can also entrench inequality: in unequal societies, migration already prompts security-driven responses such as gated communities and segregated living to keep poorer people at a distance. Many affected people will also try to cross international borders. Their motives are often labelled “economic,” but economic collapse and loss of livelihoods are frequently direct outcomes of climate shocks—droughts that destroy crops, floods that wash away farmland, saltwater intrusion that ruins wells. Treating climate and economic drivers as separate is misleading.
There are stark inequalities in responsibility and impact. The richest 1% emit as much carbon as the poorest two-thirds, and historical emissions are heavily concentrated in the global North. Those who have contributed least to greenhouse gases are often the most vulnerable and least able to adapt, so they are disproportionately likely to be displaced.
At the same time, richer countries are increasing migration policing. In the US, recent legislation would allocate nearly US$30 billion to ICE enforcement and deportation operations, triple its current budget; authorize about $45 billion for new detention centres (a very large expansion relative to other national budgets); and earmark $46.6 billion for additional border infrastructure. Under such plans, immigration enforcement agencies could become among the largest domestic security forces.
In the UK, the government has proposed asylum and returns policies framed around deterrence and “robustly enforced” rules; critics warn these measures could lead to large-scale raids and rapid deportations. The EU’s 2028–34 budget proposal allocates tens of billions of euros to border management and migration, including a marked expansion of Frontex’s resources. Taken together, proposals in rich countries effectively triple current migration and border spending in some blocs.
Borders are more militarized than at the end of the Cold War. After decades of globalization, many states are reterritorializing, constructing fortified barriers against perceived unwanted flows. More than 70 new international barriers have gone up in the past two decades: Poland’s fence with Belarus, Greece’s barriers on the Turkish border, Turkey’s wall on its Iranian frontier, new sections of the US–Mexico border wall, and Israeli barriers around Gaza and through parts of the West Bank. These fortifications often reflect efforts to control land and resources as much as they do to manage migration.
The intensification of border controls raises urgent human-rights questions. In July 2025 the International Court of Justice affirmed that states have legal responsibilities to address and compensate for climate change and can be held accountable for emissions. That ruling underlines a broader dilemma: the international community can prioritize universal rights by sharing resources and supporting adaptation, or it can attempt to shield a small wealthy minority behind walls, enforcement and deportation.
The choices made now will shape whether climate-driven displacement is met with solidarity or with securitized exclusion. The scale of projected migration and the concentrated responsibility for causing climate change suggest that ethical and practical imperatives point toward cooperation, investment in adaptation, and fairer resource sharing. Yet current policy signals in many wealthy countries point toward expanded borders, greater detention and deportation capacity, and the deepening of global inequalities. The outcome will determine who is protected and who is pushed into precarious movement in a warming world.
Andrea Rigon is professor, Politecnico di Milano, and UCL.
This article is republished from The Conversation under a Creative Commons license.
