
by Claire Loewen, McGill University
edited by Gaby Clark, reviewed by Robert Egan
Sea level rise could put more than 100 million buildings across the
Global South at risk of regular flooding if fossil fuel emissions are
not curbed quickly, according to a new McGill-led study published in npj Urban Sustainability. Exposure to building inundation as a function of LSR. Credit: npj Urban Sustainability (2025). DOI: 10.1038/s42949-025-00259-z Sea level rise could put more than 100 million buildings across
the Global South at risk of regular flooding if fossil fuel emissions
are not curbed quickly, according to a new McGill-led study published in npj Urban Sustainability.
Millions of buildings at risk, even in best-case scenario
The study considered scenarios of between 0.5 and 20 meters of sea
level rise. It found that with a rise of just 0.5 meters, a level
projected to occur even under ambitious emissions cuts, approximately
three million buildings could be inundated. Under scenarios with five
meters or more of rise, as could be expected within a few hundred years
if emissions don't end soon, exposure increases sharply, with over 100
million buildings at risk.
Many of these buildings are in densely populated, low-lying areas, meaning that entire neighborhoods and critical infrastructure, including ports, refineries and cultural heritage sites, would be affected.
"We were surprised at the large number of buildings at risk from
relatively modest long-term sea level rise," said Prof. Jeff Cardile,
co-author and professor at McGill University. "Some coastal countries
are much more exposed than others, due to details of the coastal
topography and locations of buildings."
Critical insights for urban planners, policymakers, communities
The researchers argue that these findings offer critical insights for urban planners, policymakers and communities working to prepare for inevitable sea level rise.
"Every one of us will be affected by climate change and sea level
rise, whether we live by the ocean or not," said Eric Galbraith, another
professor involved in the study at McGill. "We all rely on goods, foods
and fuels that pass through ports and coastal infrastructure exposed to
sea level rise. Disruption of this essential infrastructure could play
havoc with our globally interconnected economy and food system."
The study's interactive map, publicly available via Google Earth Engine, allows decision-makers
to visualize which regions face the greatest exposure. This data can
inform climate adaptation strategies such as building protective
infrastructure, adjusting land use planning or, in some cases, managed
retreat.
"There is no escaping at least a moderate amount of sea level rise,"
said Maya Willard-Stepan, lead author who conducted the study as part of
an undergraduate research project . "The sooner coastal communities can
start planning for it, the better chance they have of continuing to
flourish."
More information:
M. Willard-Stepan et al, Assessing the exposure of buildings to long-term sea level rise across the Global South, npj Urban Sustainability (2025). DOI: 10.1038/s42949-025-00259-z