Researchers from Kiel University and the University of Southampton projected populations of coastal cities. They found that more than a billion people could live in these low-lying areas by 2060. Click through to see the countries with populations most exposed to sea-level rise. (Joe Raedle/Getty Images)

People around the world are heading for the shores, but not for a day at the beach. By the year 2060, a billion could live along the coasts, at or below elevations of 10 meters (32 feet). Couple that with the fact that ocean waters are steadily increasing, and many more people could potentially face storm-surge flooding, coastal erosion and other challenges resulting from sea-level rise.

“Two-thirds of the world’s megacities are located in the coastal zone,” Barbara Neumann, of Germany’s Kiel University, told weather.com. “We assume that this trend of migration to coastal areas will continue.” Neumann, along with colleagues from the United Kingdom’s University of Southampton, Wednesday, Mar. 11, 2015, in the journal PLOS One.

Some of the research confirmed what’s already known, for example, that more than 80 percent of low-lying communities reside in less developed countries, many of which are in Asia and Africa. What surprised Neumann, however, was the inclusion of more developed countries on the list of those with highest exposure to sea-level rise.

(MORE:)

In the United States — which ranked eighth on the overall list — nine percent of the population or 23.4 million people live in the low-elevation coastal zone or LECZ, as the researchers describe it. “These numbers could grow up to 43.8 million by 2060, assuming very high population growth,” Neumann said. Japan, Brazil, the United Kingdom, Argentina and the Netherlands also made it into the top 25.

To get to these results, the scientists looked at four complicated scenarios for the years 2030 and 2060, taking into account “global economic growth” and “political, social and economic governance.” Picture a grid, with economics across the top and governance down the right-hand side. The scenarios move along a continuum. In Scenario B, for example, there’s very low population growth; C shows ballooning populations paired with high rates of people moving to the coast. Two extremes, Neumann said.

This research, she added, wasn’t about fear-mongering or pushing an agenda. “One of the messages of our study: It’s not that we want to be alarmist about climate change and sea-level rise. It’s more like just getting new numbers and knowing, how many people are we talking about and where are the problem areas?” That will help set a new baseline, she explained.

The article, “,” ran in PLOS One.

MORE FROM WEATHER.COM: