How to Prepare for Sea Level Rise: Follow New Hampshire’s Lead

July 16, 2015 | 12:46 pm
Aaron Huertas
Former Contributor

New Hampshire has the nation’s shortest coastline, at less than 20 miles, but don’t let that statistic fool you: when scientists count its bays, tidal rivers, and salt marshes, they tally more than 230 miles of so-called inland tidal shoreline. These areas are vitally important for New Hampshire’s economy, especially when it comes to tourism and shipping. They’re also vulnerable to coastal flooding, which is why the state is using the best available science to plan for the future, including rising seas.

Given the fact that presidential candidates have logged more than 400 trips to the Granite State in the past year, I hope they’re paying attention. After all, they’re vying to lead a country with more than 12,000 miles of coastline.

Portsmouth, New Hampshire is one of the nation’s oldest port cities. Source:

Portsmouth, New Hampshire is one of the nation’s oldest port cities. Source:

Sea level rise is a new factor in centuries-long challenges with coastal flooding

Coastal communities have long dealt with erosion and land subsidence; now they also have to deal with sea level rise from industrially driven climate change.

While future sea level rise is often painted in hopelessly dire terms—and believe me, I’m not here to discount how serious the issue is—it presents significant long-term challenges worth preparing for now. Engineers and coastal planners are finding that canal systems, pump stations, and even sewer pipes—things we take for granted as part of modern life—will need updating to account for rising seas.

Floodwaters don’t care what political party you’re in

A cubic foot of sea water weighs 64 pounds. And it weighs 64 pounds whether a coastal community is represented by Democrats or Republicans. Water is water and it can pack a heavy punch when a storm moves it quickly inland.

Policymakers in New Hampshire understand this. In August 2013, they created a Coastal Risk and Hazards Commission to help the state prepare for flooding and sea level rise. The legislation was sponsored by Nancy Stiles, a Republican state senator from Hampton, and two Democratic state senators, David Watters of Dover and Martha Fuller Clark of Portsmouth.

Obviously, it would be great to see more cross-party cooperation like that at the national level, too.

Science is a darn good tool for understanding our world

The commission convened a panel of experts, including from the University of New Hampshire, to produce an advisory report. Panel members also included those who are skeptical about mainstream climate science, which ensured that all voices were heard.

Sea-level rise scenarios for New Hampshire, where a scientific advisory panel laid out future potential sea-level rise and made recommendations for how to plan in response. Source. NH Coastal Hazards Planning Commission.

Sea level rise scenarios for New Hampshire, where a scientific advisory panel laid out future potential sea level rise and made recommendations for how to plan in response. Source: NH Coastal Hazards Planning Commission.

The report includes practical recommendations for local and state officials based on how long they expect projects to endure and a range of risks we’re likely to face as sea levels rise. As climate science nerds will happily tell you, future sea level rise depends largely on how much more heat-trapping emissions go into the atmosphere and how quickly land-based ice melts in response to warming. Thus the double-barreled uncertainty that produces a wide range of future sea-level rise scenarios that are all worth considering.

On a recent visit to New Hampshire, the Rockingham Planning Commission’s Julie LaBranche helpfully explained the specifics of the report:

If a town were building a new pump station to manage flooding and expected that station to be in service for 30 years the report recommends that the town plan on managing 1.3 feet of sea level rise above today’s levels and consider ways to modify the infrastructure over time to possibly manage 2 feet of sea level rise.

A causeway in coastal New Hampshire, in October 2011—inches from the reach of high tide.

A causeway in coastal New Hampshire, in October 2011—inches from the reach of high tide.

If something was designed to last past 2050, such as a new wastewater treatment plant, the risk increases to 3.9 feet of sea level rise with the possibility of as much as 6.6 feet by the end of the century.

Whenever I see reports like this, I’m struck by how useful they are. Why would anyone want to build something without taking advantage of the latest scientific knowledge about our coasts? At the most practical level, we want to build infrastructure that can last into the future – not infrastructure that will need replacing when it floods.

Coastal communities are learning from each other and will need more support

My colleagues and I pay a lot of attention to these planning processes, including in Florida and Louisiana as well in places like North Carolina, where the state is once again considering science-based sea level rise projections after legislators voted to ignore them in 2012.

My colleague Erika Spanger-Siegfried follows them particularly closely. When she’s not writing analyses about coastal flooding, she also works with Storm Surge, a coastal adaptation workgroup in Merrimack Valley, which sits along the border between Massachusetts and New Hampshire. Erika and her neighbors are on the Massachusetts side and she’s glad they’ve found ways to learn from folks in New Hampshire. “They’re far out ahead of us,” she told me, a testament to the foresight New Hampshire legislators showed in creating the commission.

Flooding in Cashman Park in Newburyport, Massachusetts. Source:

Panorama of flooding in Cashman Park in Newburyport, Massachusetts. Source:

A few years ago, I also met Caroline Lewis, the head of the CLEO Institute in South Florida, an area that has become a national symbol of the threat of rising seas, particularly in Miami. She assured me that Miami could continue to thrive for decades—if leaders plan for the future now. And she told me she hoped other communities around the country—and the world—could learn from what Miami chooses and doesn’t choose to do. In this sense, being on the front lines of sea level rise is both a challenge and a responsibility, and Florida leaders at the county level certainly understand that, even as state officials too often avoid the issue.

We need a national plan for dealing with sea level rise

Meeting people who are actively working to protect their communities from coastal flooding has made it abundantly clear to me that we need to do more as a country to support them.

The next president, in particular, will lead agencies including the National Oceanic and Atmospheric Administration, the Federal Emergency Management Agency, and the Army Corps of Engineers, which all play a critical role in studying, protecting and reshaping our coasts. Their duties—and the assistance communities will need from them—will only grow as seas rise.

Candidates owe it to coastal states to tell them how they plan on dealing with sea level rise over the next four years. As they pass through these states, especially New Hampshire, I hope we learn what those plans are.