Local Climate Change Risks Exposed: Chatham’s Geography Makes It Vulnerable

CHATHAM – Climate change is already touching everyone’s lives, but perhaps nowhere as dramatically as in coastal communities like Chatham. A forum sponsored by the Chatham Climate Action Network Thursday invited four experts to talk about the risks posed by severe weather and rising sea levels, and the steps the town is taking to mitigate those risks.

 But first, panelist Chris Gloninger sought to set the record straight on climate change.

 “There’s still a lot of misconceptions,” he said. An Emmy award-winning TV meteorologist who left broadcasting in 2022 to become a climate consultant with the Woods Hole Group, Gloninger summarized the scientific basis for the idea that human activity is causing climate change. 

Since about 1880 — about the time of the industrial revolution — global temperatures have been rising, albeit with fluctuations generally related to the El Niño and La Niña oscillations in ocean temperatures. But scientific knowledge about global temperatures goes back much further than that.

 “Thermometers are a relatively new invention,” he told the crowded meeting room at the community center last Thursday. By studying tree rings, ice cores and ocean sediment, climate scientists have access to temperature data going back five million years. While some people argue that global temperatures are cyclical, records show that we are in the 536th consecutive month when the earth’s average temperature is above average. That’s a shocking statistic, Gloninger said.

 “That’s why I point to this when people push back and say, well, you know, there isn’t a consensus. There really is,” he said. “In fact, atmospheric and climate scientists have more data that shows humans are causing climate change than medical doctors have that smoking causes cancer.” There is a 99.9 percent consensus of peer-reviewed research that shows human influence over time, he noted. Other potential causes, from volcanic activity and solar flares to space lasers and weather modification, have been debunked.

 “Some people are willing to point fingers at other reasons, but literally the one that scientists have proven is the fact that carbon emissions going up is the big driver,” Gloninger said. 

 Climate change has already brought “weather whiplash” to New England, as with the recent flooding in the Merrimac Valley, which came during a period of drought. Cape Cod is a particularly vulnerable place, with thousands of people, 147 miles of road, and 6,898 homes worth a total of $5.6 billion located within five feet of sea level. Five feet is the size of the storm surge that New York experienced during Hurricane Sandy.

 “This isn’t a political issue at all. It’s science,” Gloninger said. “We have to find ways to cross the aisle to have meaningful conversation that isn’t just talking down to people, that isn’t preaching.”

 Next to speak was Joe Famely of the Woods Hole Group, who has been working with Chatham and other Cape communities on a project to identify and prepare low-lying roads for sea level rise. 

 “In Massachusetts, we are very lucky to have a state and agencies that take this issue very seriously,” Famely said. Various computer models show how rising ocean levels are likely to reshape the coastline in the decades ahead. When the rising water inundates salt marshes, the marshes gradually migrate inland to higher ground until they encounter a slope or a structure; when that happens, “we end up losing salt marsh,” Famely said. The computer models help inform coastal communities about the infrastructure that’s endangered by sea level rise, helping them plan accordingly for storm events.

 “As we have higher water levels from daily tides and higher storm surge events and bigger waves, the coast is likely to experience more erosion,” he said. 

 “Just because you have a low probability event on an annual basis doesn’t mean you don’t have to worry about it,” he said. The probability is multiplied out annually to provide a cumulative risk over time, which has implications for a 30-year mortgage on a house, or a road or a sewer pump station that has a lifespan of decades. Even if models show that a structure is exposed to a modest chance of flooding in a given year, it could have a 96 percent chance of flood exposure over a 30-year period.

 When considering the risks to roads, the low-lying roads study weighed not only the flood risk, but the potential impacts to emergency services, business activity and vulnerable populations, should the road flood. Once the highest-risk roads are identified in a community, it’s time to decide how to respond. The best is to avoid building in such areas or to move the road back, “but in a lot of cases, retreat is also hard,” Famely said. The strategy then is to either accommodate floodwaters by allowing them to pass underneath a road, or to raise or buttress the road to keep water out.

 Given its unique coastal geography, Chatham has been in the forefront of coastal preparedness. 

 “The overall approach in town is coastal resilience in every project,” said Natural Resources Director Greg Berman, the next panelist. For evidence, see the new sewer pump stations at Mill Pond and Old Mill Boatyard, which have been raised above flood level, or the elevated packing house at the trap dock pier. The town is also carrying out a two-part climate survey to help identify the climate adaptations that voters would support and to better understand energy use in the town. 

 The town is seeking grant funding for the projects, including the low-lying roads improvements, though that particular project was not funded in this round, Berman said.

 “The federal opportunities have kind of dried up a bit,” but state grants remain available, he noted. An analysis of the tide gate under Morris Island Road is moving ahead with town funding, and a contract is now in place for the study, Berman said. The town is actively involved in studies of its salt marshes, supported by the energy and climate action committee and using Community Preservation Act funds. Various strategies are being considered to make the marshes more resistant to sea level rise. 

 “What do the marshes do? They protect us,” Berman said.

 It’s an inescapable fact that coastal resilience costs money.

 “Today it’s going to cost something to adapt, very simply. But even not doing something is going to cost us in the future,” he said. Climate mitigation is money well spent and will yield “a massive benefit” in the years ahead.

 Wrapping up the panel was Catherine Ricks, Chatham’s coastal resilience director, who said that boosting “living shorelines” are key to climate adaptation since they “help to buffer areas without putting hard structures” in place. With a projected sea level rise of 3.2 millimeters each year, “our marshes are not going to keep up naturally,” she said. 

 In her previous job with the Louisiana Coastal Protection and Restoration Authority, Ricks worked on various strategies to bulk up salt marshes. In some places, the spraying of sediment on top of marshes can help them elevate over time. In places where grass and sediment are insufficient protection for the shore, a good solution can be the use of sills with shellfish that still offer a living shoreline, while giving “a little more protection against erosion.”

 In some places, a conventional hard structure is still called for, as with the bulkheads at the fish pier, Ricks noted. But if those bulkheads had been built to the height necessary to prevent storm flooding, they would have been so tall as to have made the fishing boats below unreachable, “and it would no longer be a working waterfront,” she said. So the design accommodates a certain level of flooding and protects critical infrastructure from the floodwaters. 

 “There’s a lot of money that has to go into these projects,” she said, and the town has been applying for no fewer than seven types of grants the current year alone. But those grants are becoming more competitive as other communities step up their coastal resilience efforts. 

 “Their funds for us have gone down and more people are applying for the grants, so there’s more need for them,” Ricks said.