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Senate Testimony on Sea Level Rise by Ben Strauss

Testimony for Senate Energy and Natural Resources Committee, April 19, 2012

New Report: Sea Level Rise Threatens Hundreds of U.S. Energy Facilities (PDF)
Interactive Map: Surging Seas, Sea Level Rise Analysis
News: Senate Hearing Focuses on Threat of Sea Level Rise
Watch: Ben Strauss' Senate Testimony
Watch: Archived webcast of Senate hearing
Read: Senate testimony of five witnesses

Presented by Benjamin H. Strauss

Good morning, Senator Bingaman and colleagues. Thank you for your attention to this important topic. I am Dr. Ben Strauss, coauthor of two recent peer-reviewed papers making an assessment of sea level risk to the lower 48 states, as well as the summary report submitted with my written testimony. I am also Director of the Program on Sea Level Rise at Climate Central, a nonprofit research organization that conveys scientific information to the public. We take no policy positions.

In my testimony today, as in my research, I will address two topics: first, how sea level rise is amplifying the risk from coastal storm surges, and then, what communities and assets are exposed at the lowest elevations.

The nearest-term sea level projections I will share, in inches, may sound small. But they are dangerous. The key problem is that rising seas raise the launch pad for coastal storm surges, and tilt the odds toward disaster. Just a few extra inches could mean the difference to flood a family’s basement — or New York City’s subway system, disabling it for months. You might think of it this way: raising the floor of a basketball court would mean a lot more dunks.

In the long term, we are likely to see many feet of sea level rise, and be forced to redraw the map of the United States. The high end of projections for this century would be enough to turn Miami-Dade County, Florida, into a collection of islands. But in the near term, we will mainly experience sea level rise as more and more coastal floods, reaching higher and higher.

In fact, according to our analysis, sea level rise due to global warming has already doubled the annual risk of extreme coastal flooding across widespread areas of the nation. Global average sea level has risen about 8 inches since 1880. This means that warming is already contributing to the damage caused by any coastal flood today. Diverse studies bracket additional global rise likely this century between 1 and 7 feet.

In some areas, especially for Louisiana, Texas, and mid-Atlantic states, sinking land will add to the total effective rise and compound problems. Taking such local factors into account, we made mid-range projections for sites around the lower 48 of 1-to-8 total inches increase by 2030, and 4-to-19 inches by 2050, depending upon location. All along the Pacific, from Seattle to the Oregon coast to San Francisco to Los Angeles, the component of past and projected sea level rise from global warming more than triples the odds of “century” floods by 2030 in our analysis, as you can see from the display. The same is true inside the Chesapeake and Delaware Bays, and many sites to the north.

These increases are likely to cause a great deal of damage. At more than half the 55 sites where we studied flood risk, storm surges on top of sea level rise have better than even chances to reach more than 4 feet above the high tide line by 2030. Yet nearly 5 million U.S. residents live in 2.6 million homes on land below this level. Multiplied by the national average sales price of existing homes in 2010, this stock comes to more than $500 billion of residential real estate, in a rough estimate.

An enormous amount of infrastructure also lies in the same zone, from airports to wastewater treatment plants, and including nearly 300 energy facilities — as you can see in the second display, along with values for some individual states, and population figures. The facilities shown are mainly natural gas, oil and gas, and electric facilities. More than half are in Louisiana, the vast majority there unprotected by levees.

In 285 municipalities, more than half the population lives on land below the 4-foot mark. One hundred and six of these places are in Florida and 65 are in Louisiana. In 676 towns and cities spread across every coastal state in the lower 48 except Maine and Pennsylvania, more than 10 percent of the population lives below the 4-foot mark. Maps and statistics for 3,000 coastal towns, cities, counties and states are searchable by name or zip code at, and I urge you and your colleagues and staff members to explore the places important to you.

In conclusion, the risks from sea level rise are imminent and serious; this is not a distant problem only of concern for our children. Escalating floods from sea level rise will affect millions of Americans, and threaten countless billions of dollars of damage to buildings and infrastructure.

Thank you for your attention.


By Byron Smith (Edinburgh)
on April 19th, 2012

Excellent! Thanks for posting this.

One small thought - if you have taken “the national average sales price of existing homes in 2010” as a benchmark for estimating potential property values at risk, then wouldn’t this likely be a significant underestimation of risk, given that (absent widespread awareness of the threat from SLR) coastal and beachfront property generally command a premium on price?

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By dan in illinois
on April 20th, 2012

“Global average sea level has risen about 8 inches since 1880.”

Wait a minute - I thought Global Warming was a recent phenomenon.  If the sea level has risen without Global Warming, what caused that?  This Climate Change stuff is really complicated!  Good thing for you experts here to make these fancy predictions.

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By Craig King
on April 21st, 2012

What will cause these sea level changes when there is nothing anywhere in the record that would indicate a quickening but in fact just the opposite, it has been slowing over the last few years?

However once you accept the rise in sea level as being a fact then the rest of this presentation is entirely consistent. A bit like saying DDT will kill us all so it must be banned. Even though, as we all know, DDT will not kill us all.

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By Gabe (Seattle/WA/98028)
on April 23rd, 2012


DDT won’t “kill us all”, right away. It was banned because it killed off the things that make our ecosystem function. Without the biodiversity of the lower level ecosystem, our environment would be wrecked.  DDT binds to fat.  In the United States, DDT and metabolites were detected in almost all human blood samples tested by the Centers for Disease Control in 2005, though their levels have sharply declined since most uses were banned in the US! DDT’s half-life in the human body is 6-10 YEARS.

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