Here's How Many Buildings Are Threatened by Rising Seas

That rising seas could threaten some coastal buildings is no surprise—but just how many may startle you. A sweeping new study that looks specifically at the Global South—so along the coasts of Africa, Southeast Asia, and Central and South America—warns that tens of millions of buildings could be at risk. Researchers from McGill University analyzed satellite maps and elevation data to estimate how the roughly 840 million buildings in the region would fare under scenarios of between 0.5 and 20 meters of sea level rise. Their findings were published in npj Urban Sustainability.

Even if the world manages to significantly cut emissions and keep sea level rise to 0.5 meters, about 3 million buildings could be swamped. But the researchers say if emissions keep climbing and seas rise by 5 meters or more, the number of imperiled buildings jumps to 45 million; at 20 meters, it's 136 million. Many of these structures sit in crowded, low-lying zones, putting entire neighborhoods, essential infrastructure, and cultural landmarks in jeopardy. "We were surprised at the large number of buildings at risk from relatively modest long-term sea level rise," said co-author Prof. Jeff Cardille, per a release.

If you're inclined to wave off the findings because they don't seem geographically relevant, the research team stresses that no one is immune to the fallout. As study author Eric Galbraith points out, "We all rely on goods, foods, and fuels that pass through ports and coastal infrastructure exposed to sea level rise."