From New York to Shanghai, coastal cities around the world are at risk from rising sea levels and unpredictable storm surges. But rather than simply building higher seawalls to hold back floodwaters, many builders and urban planners are turning to floating and amphibious architecture — and finding ways to adapt buildings to this new reality.

Some new buildings, including a number of homes in Amsterdam, are designed to float permanently on shorelines and waterways. Others feature special foundations that let them rest on solid ground or float on water when necessary. Projects range from simple retrofits for individual homes in flood zones to the construction of entire floating neighborhoods — and possibly even floating cities.

“It’s fundamentally for flood mitigation, but in our time of climate change where sea level is rising and weather events are becoming more severe, this is also an excellent adaptation strategy,” says Dr. Elizabeth English, an associate professor at the University of Waterloo School of Architecture in Ontario. “It takes whatever level of water is thrown at it in stride.”

New kind of flood readiness

From ground level, amphibious houses look like ordinary buildings. The key difference lies with their foundations, which function as a sort of raft when the water starts to rise.

In some cases, existing homes can be retrofitted with amphibious foundations to give people in flood-prone areas a less costly alternative to moving or putting their homes on stilts, says English, founder of Buoyant Foundation Project, a nonprofit based in Breaux Bridge, Louisiana and Cambridge, Ontario. “What I’m trying to do is to take existing communities and make them more resilient and give them an opportunity to continue to live in the place that they’re intimately connected to,” she says.

There are also new constructions built with amphibious foundations, such as a home designed by Baca Architects on an island in the River Thames in Marlow, England. When waters are low, the house rests on the ground like a conventional building; during floods, it floats on water that flows into a bathtub-shaped outer foundation.