Want To Know How Sea Level Rise Will Impact Your Hometown? There’s A Map For That

First published on ClimateProgress.org, a project of the Center for American Progress Action Fund, which was recently named one of Time magazine’s Top 25 blogs of 2010.

If you want to know whether your city has the potential to be underwater due to rising sea levels, there’s now a map for that.

In conjunction with research published Monday in the Proceedings of the National Academy of Sciences, Climate Central launched ‘Mapping Choices,’ an interactive tool that lets users compare sea level rise in different cities based on various carbon scenarios, from aggressive carbon cuts to unchecked pollution.

“I think we read a lot of projections about future temperature increases or impact, but it can be hard to understand what they really mean,” Ben Strauss, vice president for sea level and climate impacts at Climate Central and lead author of the study, told ThinkProgress. “We wanted to do a research project that would literally give people a picture, or a map, of the different outcomes that we could see. This is a story that can have different endings, and the endings depend on what we do.”

If left unchecked, carbon pollution could lead to between 14 and 33 feet of long-term global sea level rise, the study found. That magnitude of sea level rise would threaten to submerge land that is currently home to between 20 and 31 million Americans, including at least 20 major U.S. cities with more than 100,000 residents. With aggressive carbon cuts, the study found, half of these cities could be spared from rising seas — but major cities like New Orleans and Miami are likely to be permanently threatened by rising sea level even with aggressive action on climate change.

In addition to looking at sea level rise, the study looked at “lock-in dates” for long term sea level rise — dates beyond which the effect of carbon emissions doom the cities to inundation. Under a high-carbon pathway (RCP 8.5), a quarter of Boston would be “locked-in” to long term sea level rise around 2045, and New York City would have until 2095 — but cities like Miami, New Orleans, and Charleston have already passed their lock-in date.

“Many cities have features that depend on our energy path, but some appear to be already lost,” Strauss said. “It is hard to imagine how we can defend South Florida in the long run. It is hard to imagine how we can defend New Orleans in the long run.”

To understand how carbon emissions will impact sea level rise, the researchers essentially combined two well-established lines of research — one relating to carbon emissions and global warming, and another relating warming to long term sea level rise. After combining those lines of research in what Strauss referred to as a “statistically appropriate way,” the researchers were able to build a relationship between how much carbon is emitted into the atmosphere and how much sea levels can be expected to rise. The researchers then applied that relationship to coastal topography maps, and, using census data and information about historic high tide lines, mapped the areas that would be inundated, under different carbon emission scenarios, in the future.

The time frame on inundation, Strauss explained, is long term.

“The sea levels that we’re projecting could, with a small chance, occur as soon as 2200, but they might take many more years to unfold,” he said.

But Strauss underscored the idea that even though sea level rise could take centuries to reach catastrophic levels, the choices society makes in the coming decades will have a large impact on just how high the global waters will go.

“We’re doing our best to make this challenge concrete by showing you what it means for your zip code, your city, the places you care about, and explaining why the consequences may take a long time to unfold,” Strauss said. “Some of America’s most culturally important cities are at stake. Not just Miami and New Orleans, but New York, Washington, D.C., Philadelphia, Boston. Will we preserve and protect our great coastal cities, or will we not? The answer depends on how much carbon we put in the atmosphere.”

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