Picture Miami in 2060. Not underwater yet, but close enough that insurance companies stopped writing policies a decade ago. The question isn't whether millions will move—it's who pays for it and where they go.

Climate migration isn't some distant hypothetical. It's already happening, from Louisiana's disappearing coastline to Bangladesh's shrinking delta. What makes this different from past migrations is scale. We're talking about hundreds of millions of people moving within decades, and the economic ripples will touch everyone—even those who never budge.

Moving people is expensive. Moving entire cities is almost incomprehensibly so. When we talk about relocating coastal populations, we're not just talking about helping families pack moving trucks. We're talking about building new hospitals, schools, water systems, and power grids from scratch.

Consider this: roughly 40% of the global population lives within 100 kilometers of a coastline. In the United States alone, coastal counties generate over $9 trillion in economic activity annually. The infrastructure serving these areas—roads, bridges, sewage treatment plants—took generations to build. Replicating even a fraction of it elsewhere means infrastructure investment measured in trillions, not billions.

The financing question is brutal. Governments already struggle with existing infrastructure backlogs. Now add the need to simultaneously maintain declining coastal areas while building new capacity inland. This isn't a problem that market forces alone can solve. It requires coordinated public investment on a scale we've rarely attempted outside of wartime.

Takeaway

Infrastructure follows people, but people move faster than infrastructure can be built. The economic burden falls not just on those who move, but on taxpayers everywhere who fund the public systems those migrants need.

Every migration wave creates winners and losers. Climate migration will be no different, except the numbers involved dwarf anything in modern history. Receiving regions will face a sudden influx of workers, while departing regions lose their economic base.

Here's where it gets interesting economically. When skilled workers leave vulnerable areas, they take their productivity with them. A nurse fleeing coastal flooding doesn't stop being a nurse—she just practices medicine somewhere else. Receiving regions gain human capital they didn't train or educate. The Florida exodus could become Tennessee's workforce boom.

But absorbing large populations quickly creates friction. Housing markets tighten. Wages in some sectors face downward pressure as labor supply increases. Local services strain under unexpected demand. The economic opportunity is real, but so is the adjustment cost. Cities that plan ahead—building housing, expanding public transit, investing in education—will capture the benefits. Those caught flat-footed will experience the disruption without the upside.

Takeaway

Climate migration redistributes human capital across geography. Regions that prepare for population growth will transform crisis into economic opportunity; those that don't will bear the costs without the benefits.

Our instinct is to fight the water. Build seawalls. Raise roads. Pump sand onto eroding beaches. But engineering solutions have limits, and those limits have price tags. At some point, the math stops working.

Economists call this the adaptation tipping point—the moment when defending a location costs more than relocating its population and economic activity. For many coastal areas, we're approaching or have already crossed that threshold. A seawall might buy twenty years, but if it costs $50 billion and only delays the inevitable, those resources would create more value invested in relocation infrastructure.

The hardest part isn't the economics—it's the politics. Nobody wants to tell communities their hometown is economically unviable. But managed retreat, done thoughtfully over decades, costs a fraction of emergency evacuations and disaster recovery. It means families move with savings intact rather than fleeing flooded homes with nothing. The economic case for planned relocation is overwhelming. The challenge is building political will before crisis forces our hand.

Takeaway

Defending every coastline is neither possible nor economically rational. The question isn't whether to retreat from some areas, but whether we do so thoughtfully at lower cost or chaotically at higher cost.

Climate migration will reshape property values, labor markets, and government budgets for the rest of this century. The economics aren't mysterious—they follow predictable patterns of supply, demand, and public investment.

What matters now is whether we treat this as a slow-motion emergency to be managed or a distant problem to be ignored. The costs are coming either way. Planning just lets us pay less.