A new McGill University-led study has issued a stark warning that more than 100 million buildings across the Global South could face regular flooding in the coming centuries if fossil fuel emissions are not reduced rapidly. The research is the first of its kind to assess the long-term impact of sea level rise on a building-by-building scale across Africa, Southeast Asia, and Central and South America.
Using advanced satellite mapping and elevation data, scientists estimated how many structures would be inundated under different scenarios of sea level rise ranging from 0.5 to 20 metres. The results reveal an alarming picture of future coastal vulnerability particularly for densely populated and low-lying regions.
Rising Seas, Growing Threat
“Sea level rise is a slow but unstoppable consequence of global warming,” said Professor Natalya Gomez, Canada Research Chair in Ice Sheet–Sea Level Interactions at McGill University and co-author of the study. “People often talk about sea level rising by a metre, but in reality it could continue for many metres if fossil fuel burning doesn’t stop soon.”
Even in the most optimistic case with only half a metre of sea level rise around three million buildings could be affected. Under scenarios exceeding five metres, expected over the next few hundred years without aggressive emissions cuts the number of at-risk buildings surpasses 100 million.
Many of these structures are vital to local and global economies, including homes, schools, hospitals, ports, and refineries. “We were surprised at how large the exposure is, even under relatively modest sea level increases,” said Professor Jeff Cardile, another co-author. “The risk varies sharply from country to country depending on coastal elevation and building patterns.”
Planning for the Unavoidable
The researchers emphasize that while some degree of sea level rise is inevitable, immediate global action can still prevent catastrophic outcomes. Their interactive map, accessible through Google Earth Engine, allows policymakers and urban planners to identify high-risk regions and design targeted adaptation strategies.
“Every one of us will be affected by sea level rise, whether or not we live near the coast,” noted Professor Eric Galbraith, another co-author. “Our ports, food supply chains, and energy infrastructure are all connected through vulnerable coastal systems. Any major disruption could ripple across the global economy.”
Adapting to a Rising Future
Lead author Maya Willard-Stepan, who conducted the research as part of an undergraduate project, stressed the need for proactive planning. “There is no escaping a moderate amount of sea level rise,” she said. “The sooner communities start preparing, the better chance they have of surviving and thriving in a changing world.”
The study calls for a combination of adaptation measures including coastal protection, resilient urban design, and in some cases, managed relocation to reduce long-term risks. It also reinforces a growing consensus among climate scientists: without swift and sustained emissions cuts, the cost of inaction will reshape coastlines and lives for generations to come.