- A collapse of the Atlantic Meridional Overturning Circulation (AMOC), a major system of ocean currents, would sharply cool the far north and modestly cool much of the rest of the Northern Hemisphere. This cooling would reverse the usual pattern in which climate change hurts developing regions most and spares, or even benefits, advanced northern economies, narrowing the gap between rich and poor regions.
- Under a moderate-emissions scenario, a collapse would lower global welfare, a measure of overall well-being that combines income and quality of life, by 1.9% by 2200 relative to a world with warming but no collapse. Losses would be concentrated in Scandinavia, Russia, Canada, and northwestern Europe, while parts of Africa, Latin America, and Southeast Asia would gain.
- Migration is a key buffer. Scandinavia’s population would fall by roughly a quarter as people move away from the cold, and blocking that movement would worsen global welfare losses by an additional 2.1%.
What Is the AMOC?
The Atlantic Meridional Overturning Circulation (AMOC) carries warm, salty surface water from the subtropics toward the North Atlantic, where the water cools, sinks, and flows back south. The delivery of warm water north helps keep Western and Northern Europe relatively mild for their latitude. Rome, for example, is about 18°F warmer than Chicago during the winter, even though the two cities sit at roughly the same latitude.
Global warming threatens to disrupt this cycle. As the North Atlantic warms and Greenland’s ice sheet melts, the surface water becomes warmer and less salty. This less dense water is less apt to sink and flow back south and therefore slows the AMOC. Eventually this pattern becomes self-reinforcing: a slower current brings less salty water back north, which makes the surface water even lighter.
Recent estimates suggest the slowing of the AMOC becomes self-reinforcing at about 5.4°F (3°C) of warming above preindustrial levels, making a collapse before 2100 more likely than not under moderate carbon emissions. Once that threshold is crossed, the collapse would likely unfold gradually over the following century.
How Would a Collapse Impact
the Economy?
In this paper, the authors estimate how an AMOC collapse would affect local economies across the world. They construct a model that divides the globe into a grid of 1-degree by 1-degree cells and quantifies, for each cell, how temperature changes would affect productivity and quality of life through 2200. The model then simulates how people and businesses respond to these changes by migrating, shifting trade, and investing in innovation. Under moderate emissions, the model yields the following estimates of how an AMOC collapse would affect population, GDP, and overall welfare by 2200:
- In the far north, cooling reduces both productivity and quality of life. Winter temperatures near Svalbard fall by more than 45°F, pushing already cold regions further below the temperatures at which they are most productive and most livable. Welfare falls sharply in Canada, Russia, and Scandinavia, with some locations losing more than 20%.
- Farther south, milder cooling eases the damage from heat. In regions that are already hot, a modest drop in temperature boosts productivity and quality of life. Welfare rises along the Mediterranean and in North Africa, Brazil, and Southeast Asia, though gains are modest, mostly between 1% and 5%.
- This reverses the usual pattern of climate damage. Without an AMOC collapse, warming falls hardest on developing regions near the equator, while Scandinavia, Russia, and Canada gain from milder winters. With a collapse, the regions hurt most by warming instead benefit most, and inequality across regions narrows.
- Overall, the world loses welfare under an AMOC collapse. Despite reversing some of the effects of global warming, a collapse lowers aggregate welfare by 1.9% in 2200 relative to a world that experiences global warming but no collapse. This reflects welfare losses being concentrated in the relatively productive northernmost latitudes, where cooling is most severe.
- In some parts of Europe, cooling raises productivity but lowers quality of life. Earlier work by two of the authors finds that productivity peaks at an average winter temperature of about 35°F, while quality of life peaks at a milder 47°F. In northern Europe, where winters are already colder than both, cooling lowers productivity and quality of life, and welfare losses are steepest. In places with winter temperatures between 35°F and 47°F, which include much of Western Europe, from the UK and Germany to the Benelux countries and parts of France, cooling moves them toward the productivity peak and away from the quality-of-life peak. There, productivity gains are not enough to offset the decline in quality of life, and welfare still falls. Only in the warmest areas, near the Mediterranean, does cooling improve quality of life as well, and welfare rises. On net, Europe loses 3.3% of its welfare, well above the 1.9% global loss.
- People leave the cold in large numbers. By 2200, an AMOC collapse reduces Scandinavia’s population by 25.6%, Russia’s by 17.8%, the rest of Europe’s by 7.1%, and North America’s by 4.1%. The Middle East, Africa, and Latin America gain roughly 1% to 2%. Regional GDP shifts by similar amounts.
- Blocking migration steepens welfare losses. In a counterfactual where people cannot relocate, global welfare falls an additional 2.1%. Density in the north stays high even as the land becomes less productive, which depresses wages and worsens crowding.
An AMOC collapse would reverse who bears the burden of climate change while leaving the world worse off overall. How large those losses are depends heavily on whether people can adapt. When they are free to move away from regions that become colder and less productive, the damage is substantially smaller, underscoring migration’s role as one of the most important ways economies absorb climate shocks.
