Hundreds of thousands of coastal homes in the United States are at risk from the effects of climate change on sea levels in the next three decades, according to new research.

The study from real estate firm Zillow using a coastal analysis from Climate Central, points out that this includes thousands of new homes in coastal states that have recently been built in areas that are at risk of chronic flooding within just a few decades.

Overall, some 400,000 properties homes are likely to be at risk of regular flooding by 2050, the analysis shows but moderate emissions cuts could reduce the number of current homes in at-risk areas to 348,000 by 2050.

Because the effects of climate change will worsen over time, the estimates for the year 2100 are far higher with 1.3 million current homes anticipated to be at risk of regular flooding if emissions are cut moderately, and 2.5 million homes worth $1.3 trillion if emissions grow unchecked.

The report says that as sea levels rise, the intermittent floods that coastal communities now experience on average once a year are projected to reach farther inland than they do today. Those floods can damage and devalue homes, degrade infrastructure, wash out beaches, and interrupt transportation systems and other aspects of daily life. They also put home owners, renters and investors in danger of steep personal and financial losses.

‘This research suggests that the impact of climate change on the lives and pockets of home owners is closer than you think. For home buyers over the next few years, the impact of climate change will be felt within the span of their 30 year mortgage,’ said Skylar Olsen, Zillow’s director of economic research and outreach.

‘Without intervention, hundreds of thousands of coastal homes will experience regular flooding and the damage will cost billions,’ he added.

The report explains that coastal communities will encounter the effects of sea level rise to greatly varying degrees, depending on the local rate of rise, local tides and storms, the potential future development of coastal defences, the flatness of the landscape and where homes are built within it.

Some major coastal cities, including Los Angeles, sit high enough above sea level that the biggest hit, even as far out as 2100, will be to their beaches. Others will suffer more far-reaching and damaging effects.

For example, about 10% of homes in Galveston, Texas, and 7% in Ocean City, Maryland, are projected to be at risk of at least annual flooding by 2050, if the world makes moderate emissions cuts, numbers that rise to nearly half of the homes in each community by 2100.

By the same year, Hoboken in New Jersey and Miami Beach in Florida, could see three quarters or more of their homes at risk of at least annual flooding, if emissions remain unchecked.

When it comes to new homes still being built at striking rates in areas that face high risks of future flooding, it is projected that in New Jersey some 7% of current homes could be in flood risk zones by 2100, under moderate emissions cuts. But because of ongoing development, 14% of the state’s homes built from 2010 through 2017 are in the same high risk areas.

‘A combination of Zillow’s data with Climate Central’s coastal analysis has given us our most detailed picture yet of U.S. homes at risk from rising seas,’ said Dr. Benjamin Strauss, chief executive officer and chief scientist of Climate Central.

‘And we have discovered that many communities are growing faster in areas facing chronic future floods than they are in higher areas. It’s difficult to plan for higher seas if you are busy digging deeper holes,’ he added.