Rising sea levels, driven by climate change, may wipe out some of the famous coastal cities in the world, including Mumbai, by 2050 and affect three times more people than estimated before, according to research published in the journal Nature on Tuesday.

The paper’s authors – New Jersey-based nonprofit Climate Central’s Scott A Kulp and Benjamin H Strauss – developed a more accurate method of estimating the effects of sea level rise, and found that about 150 million people are currently living on land that may be below the high-tide line by midcentury.

Scott A Kulp explained to The New York Times that standard elevation measurements calculated using satellites struggle to differentiate the actual ground level from the tops of trees and buildings. As a result, he and Strauss used artificial intelligence to figure out the rate of error and correct the numbers.

“Total and marginal exposure each rise by another 50 (20-90) million people by end of century,” the researchers said. “A total of 360 (310-420) million people are on land threatened by annual flood events in 2100, or an extra 110 (60-170) million beyond the contemporary baseline.”

This projection is based on curbs in greenhouse gas emissions “roughly consistent” with warming of 2 degrees Celsius and assumes a mostly stable Antarctic. “In the case of Antarctic instability, a total of 300 (270-340) million people today live on land indicated as vulnerable to an annual flood event by mid-century, rising to as many as 480 (380-630) million by 2100.”

Among the coastal cities that are under threat is India’s financial capital Mumbai. The new projections show that most of the city, especially the southern part, is at the risk of going under water, according to The New York Times. South Vietnam is projected to almost disappear, affecting more than 20 million people. Most of Ho Chi Minh City, the country’s economic centre, will be wiped out.

Some of the other regions that may be in peril are Thailand’s Capital Bangkok, Shanghai and surrounding cities in China, the ancient city of Alexandria in Egypt, and the Iraqi city of Basra.

Now, follow and debate the day’s most significant stories on Scroll Exchange.