South County Coastline Fades Away as Carbon Emissions Pile Up
May 31, 2021
Along the Rhode Island coast from Watch Hill to Point Judith, change is happening fast. From 5,000 to 150 years ago, coastal erosion along this stretch of open-ocean shoreline held steady, but it accelerated as our fondness for burning fossil fuels grew.
Coal became dominant in the late 19th century before being overtaken by petroleum products, such as oil, gasoline and diesel, in the middle of the past century. Natural gas is now the dominate fossil fuel.
The buildup of greenhouse gas emissions in the atmosphere has taken a bite out of the Ocean State’s South County coast. Erosion rates are increasing and the volume of sand is decreasing, according to John King, a longtime professor at the University of Rhode Island’s Graduate School of Oceanography. Beaches and the sand upon them protect the land behind them. Rhode Island is losing a natural defender of its developed coastline, and upland sand resources won’t last forever, even if taxpayer funding could.
King said these accelerating erosion rates are tied to the relentless burning of fossil fuels during the past century and a half that has the level of atmospheric carbon at nearly 420 parts per million. Science considers a safe level of carbon dioxide in the atmosphere — meaning one that supports human existence — to be no more than 350 parts per million.
King and his revolving team of URI researchers have been monitoring coastal changes at eight Ocean State beaches from Westerly to Narragansett since the mid-1990s. Decades of data show a highly developed shoreline eroding at a significant rate. South Kingstown Town Beach and Green Hill Beach are eroding faster than other places along the South County coast, according to King.
In the early 1960s the late Robert McMaster, a well-respected professor and researcher in the field of marine geology, initiated the URI beach monitoring project. It started with four sites and grew to its current eight. King took over these biweekly beach profiles — in June, July and August they are only performed once a month — after McMaster’s death in 1993.
At 6-decades-old, it’s the world’s longest running beach profiling study, according to URI. The project’s data were used in creating the Coastal Resources Management Council’s nationally recognized Shoreline Change Special Area Management Plan, better known as the Beach SAMP.
The rate of sea-level rise, according to the National Aeronautics and Space Administration (NASA), has risen from about 0.1 inch (2.5 millimeters) a year in the 1990s to about 0.13 inches (3.4 millimeters) a year now. It may not seem like much, but a few millimeters matter. It will matter even more when millimeters turn into centimeters.
King said when sea-level rise is less than 2.5 millimeters a year “beaches don’t retreat that rapidly and stay roughly in the same place.” That’s not what is happening now, neither along Rhode Island’s southern shore nor across the globe.
NASA notes that every inch of sea-level rise results in the loss of about 100 inches (8.3 feet) of beach. Locally, sea levels have risen nearly a foot since the 1930s. The rate of sea-level rise is also accelerating as increasing amounts of mountain glaciers and ice sheets melt and ocean waters warm. Rhode Island, like much of the rest of the Atlantic Coast, is in a sea-level-rise hot spot.
King said sea levels are rising rapidly, in geologic time, and the combination of this rise with more frequent severe weather and intense storms that linger longer are steadily damaging the coast. With the amount of carbon already baked into the atmosphere, these coastal beatings won’t be ending anytime soon. Continued burning of fossil fuels will only prolong the assault.
It’s not easy to eyeball sea-level rise at your local beach — URI’s beach-monitoring project has relied on changing technology — but its impacts are being felt in multiple ways: shoreline loss, coastal wetland inundation and dune flattening. Coastal lagoons are being filled in, and waves are “hitting the mainland with significant energy.”
“It’s not a good situation,” King said.
He noted Rhode Island, based on a few thousand years of recurrence interval data, gets hit by a Category 3 or stronger hurricane every 60-70 years. The last Category 3 hurricane was Carol in 1954, 67 years ago. We’re due, and when it strikes, King said “we’re in trouble.”
“A fair amount of unpleasant things are going to happen,” he said.
King and his team now monitor coastal changes using light detection and ranging (LiDAR) technology. The expensive equipment works by shooting a laser, from a boat traveling about 3-4 knots per hour, at the shore, which bounces back to a detection sensor. Hard or reflective surfaces return more light than soft, absorbent ones. The result is a dense group of points, each with a latitude, a longitude and an elevation.
With this data, King and other scientists can see exactly what a beach looked like at the time of the survey, and can figure out how much sand there was and where.
The increased speed of LiDAR allows more flexibility for when data is collected, such as immediately after a big storm. It also doesn’t require a U.S. Fish & Wildlife escort in the summer to make sure the nests of piping plovers aren’t disturbed.
With the changes his work has documented during the past three decades and the full collection of data amassed during URI’s ongoing beach monitoring project, King said Rhode Island shouldn’t be fooled into thinking engineering solutions are the panacea. He also noted policy change often takes too long, even when the political system is working.
Besides the obvious need to drastically cut greenhouse-gas emissions here and across the globe, climate solutions, at least when it comes to living, working and playing along the Rhode Island coast, will require retreating from the shore, buying out properties and letting nature take over, halting development in vulnerable areas, relocating roads and moving critical infrastructure such as water mains and wastewater systems.
To address the former, King said offshore wind and the electrification of the transportation and heating sectors play vital roles. For the latter, he said, “We should already be in the triage process, determining what we can do and what we can give up.”
But time is running out to get a handle on the climate crisis.
“We pissed away most of the time we had to address these impacts,” said King, noting the time for easy answers has passed. “A greater sense of urgency is required.”
To watch a PowerPoint presentation about the ongoing beach monitoring project, click here.