How Many Homes Are at Risk from Sea Level Rise? New Interactive Map Has the Answers

June 25, 2018
Kristy Dahl
Senior Climate Scientist

Last week the Union of Concerned Scientists released a report revealing that sea level rise puts over 300,000 homes in the United States at risk of increasingly frequent, disruptive flooding in just the next 30 years. Along with the report, UCS published an interactive map tool that lets you explore the exposure of coastal real estate in your state, your community, or your ZIP code to chronic flooding, or flooding that occurs 26 times or more per year (an average of every other week). It also highlights the implications of this massive risk to our economy and the importance of both acting quickly to curtail our carbon emissions and using the coming years wisely to prepare for the changes to come.

Here are a few questions you can explore with the tool:

Which states are most at risk from sea level rise?

If you’re interested in a broad overview of which states have the most homes–or the greatest property value, most people, or largest tax base–at risk of chronic flooding due to sea level rise, check out the “By State” tab of the tool:

In this tab, you can click on any state to pull up statistics on things like the number of homes at risk and the current value of those homes. You can also use the brightly-colored buttons to view the stats for different variables like the current population and tax base of at-risk properties.

The information is organized by year so you can see how this risk grows over time. The opening maps show results of our analysis of a high sea level rise scenario, but you can also scroll down to view results from a moderate sea level rise projection.

Will homes in my community or my ZIP code be affected by flooding due to sea level rise?

Similar to the “By State” tab, you can explore the risk of chronic flooding to your hometown or your neighborhood in the “By Community” and “By ZIP Code” tabs. Click on any community or any ZIP code to bring up information about the number of homes at risk, their value, the number of people living in them today, and their current property tax contribution. And like the “By State” tab, you can change the map to show the variable or year you’re interested in by clicking the buttons, and you can scroll down to see results from the moderate sea level rise projection.

When exploring the data in these two tabs, keep in mind that the way communities are defined on the ground is not always the way they are defined by the Census boundaries we used in this analysis. In some smaller towns the community boundaries we show may encompass a few small towns.

If we cut carbon emissions and future ice loss is limited, would a slower pace of sea level rise mean that fewer homes would be at risk?

The answer is a resounding YES, and the “Homes in the Balance” tab lets you explore which communities have the most to gain from a slowed sea level rise pathway. The map in this section shows how many homes could avoid chronic flooding in each community by comparing the results of our analyses of the high and low sea level rise scenarios. The low sea level rise scenario is one we should strive for, but not one we should count on. It is predicated on global carbon emissions being reduced drastically within the next decade and also requires future ice melt to be limited. Click on any community to get information on what’s at stake.

How will chronic flooding due to sea level rise affect the real estate sector and what can we do about it?

The “Challenges and Choices” section of the tool explores the broader economic implications of chronic flooding and describes how different actors in the real estate sector–from mortgage lenders to insurance providers–could be affected. It also outlines the steps we need to take, as a nation, to address this profound risk.

Improving the maps based on data and feedback

Let us know how you’re using the interactive maps to better understand the risks of sea level rise and please do send any suggestions for improvements.


About the author

More from Kristy

Kristina Dahl is a senior climate scientist for the Climate & Energy program at the Union of Concerned Scientists. She designs, executes, and communicates scientific analyses to make climate change more tangible to the general public and to policymakers. Her research focuses on the impact of climate change, particularly sea level rise and extreme heat, on people and places.