On Cape Cod, climate change casts a wide shadow
Traffic makes its way onto Cape Cod during Memorial Day weekend in 2010. The region has seen tremendous growth in the past 50 years, stressing its fragile beauty. Now climate change threatens to amplify problems associated with those changes. Photo by Let Ideas Compete/flickr.
Jan. 28, 2013
Fifty years of rapid growth have stressed resources on the Cape. Climate change will magnify these challenges.
By Jennifer Weeks
The Daily Climate
WELLFLEET, Mass. – Near the outer tip of Cape Cod, a small cottage faces west across the bay toward the mainland. Built in 1950, it measures 776 square feet – smaller than many one-bedroom apartments. It has no garage and sits on less than an acre of land at the end of a dirt road.
The house is for sale. List price: $1.5 million.
The price tag is extra-high because this is one of a few hundred private properties within the Cape Cod National Seashore, a 40-mile stretch of undeveloped coast that runs up Cape Cod's forearm. It shows the powerful draw of life here, where residents treasure a slower pace and expansive ocean views.
But the Cape’s beauty is fragile. Highways, condos and shopping centers are eating up open space. Water pollution is choking bays and ponds. Shorelines are eroding, even where residents have built seawalls and jetties to hold the land together. And over it all, threatening to alter daily rhythms of Cape life, looms climate change.
Cape Cod’s popularity far exceeds its size. It’s a 70-mile-long barrier island rimmed with curving sandy beaches and grassy marshes. More than five million tourists visit annually, and the year-round population tripled between 1960 and 2010, rising from 70,000 to 215,000. Nearly everyone on the Cape does something outdoors – commercial fishing, surfing, bird-watching, boating.
Sand, clay and rock
Physical changes have been constant on Cape Cod since glaciers pushed a pile of rock out on the continental shelf some 23,000 years ago. The Cape is made of sand, clay and rocks deposited by retreating glaciers, with no underlying bedrock. It faces the full force of Atlantic waves and weather. Henry David Thoreau, who traveled the Cape from end to end, called it "the bared and bended arm of Massachusetts ... boxing with Northeast storms."
In military planning, "force multipliers" are factors that make troop units more effective without increasing their size – for example, better training or a cutting-edge technology. Climate change will be a force multiplier on the Cape, which already is under stress from rapid growth. As sea levels rise and storms become more frequent and intense, those factors will interact with other environmental problems and make them harder to solve.
Cape Cod is famous for sand and surf, but its most urgent environmental concern is sewage.
Development patterns on the Cape reflect life before tourism, when farming and fishing were the main local industries. Homes are spread among 15 towns with no major urban center. The land in between is a mix of pine and oak scrub forests and heaths, dotted with more than 200 freshwater lakes and ponds. Secluded "kettle ponds" (holes gouged by glaciers that later filled with water) are popular spots for a quiet swim. In cool months residents rake up clams, scallops and oysters in coastal salt ponds.
These oases are at risk because only about 15 percent of Cape homes are linked to sewer lines. The rest use septic systems, which remove harmful pathogens from wastewater but do not treat nitrogen and other nutrients. These systems release treated effluent into the Cape's sandy soil, where it quickly flows into ponds, streams and bays. Nutrient pollution causes eutrophication: blooms of algae cloud the water, blocking out sunlight that aquatic plants need to grow. Then the algae die and decompose, depleting oxygen from the water and killing fish and shellfish.
"Every community on the Cape is dealing with some kind of nitrogen-related issue," said Paul Niedzwiecki, executive director of the Cape Cod Commission, a planning and regulatory agency. "Nutrient issues are destroying parts of the environment here now in a way that won't heal for generations." Over-fertilization in ponds and marshes has killed eelgrass, which provides habitat for shellfish. Many bays are clogged with algae in summer.
Most Cape towns don't have the money or technical resources to upgrade their wastewater systems, so the commission is helping them collaborate. There are plenty of technical solutions, such as equipping new homes with composting toilets and restoring marshes to serve as natural water filters. Ultimately it will cost roughly $6 billion to $8 billion to manage nutrient pollution Cape-wide, said Niedzwiecki.
And climate change could swamp poorly-designed systems. Cape Cod is only 10 miles across at its widest point, and many buildings are at sea level. According to a recent U.S. Geological Survey report, sea levels along the Cape are rising 2 to 3.7 millimeters per year – three to four times faster than globally.
"We don't want to hook up sewer systems in zones where salt water can intrude and back things up," said Niedzwiecki. "Some stretches on the south Cape could see huge overland surges from storms, so we want to keep important assets [such as pumping stations] out of those areas." The commission is using laser mapping and working with scientists to assess potential climate change impacts and threats to infrastructure.
"In every location we have to be aware that nature is changing faster than it has in the past," Niedzwiecki said.
Climate change also is amplifying natural coastal erosion, a serious issue year-round on Cape Cod. Winter storm damage can make roads impassable, and the local economy depends heavily on summer beach tourism.
Without even factoring in climate change, geologists say, Atlantic waves will probably reduce the Cape to a few islands within one or two thousand years. Now climate change is accelerating the pace of erosion. "We expect rapid change in the next five to 10 years," said Mark Adams, a mapping specialist with the National Park Service. "We see storm effects becoming more severe, and big storm and tide events are what cause drastic coastal erosion. But it's hard to quantify what fraction of the losses we see is due to climate change."
Beach erosion rates vary across the Cape, but at Provincetown's popular Herring Cove Beach, the shoreline is eroding by about 2.5 feet per year. Last winter waves gouged four separate breaches in the parking lot in front of a 1950s bathhouse. The Park Service demolished the bath house and is building new facilities, set farther back from the water and elevated to withstand projected storms.
The U.S. Geological Survey notes that bluffs along the National Seashore on the outer Cape, which are allowed to erode naturally, have worn away by about three feet per year over the past century. Some of this eroded material washes up at other spots and builds up new land, like the "hook" at the Cape's outer tip, but the rest flows out to sea. Many cliff faces are bare dirt without any anchoring grasses – a sign that the surfaces are weathering quickly.
Cape Cod resident
But for now residents dig in wherever they can. "You would think people living on a sand bar would be concerned about its future, but climate change will take a while to affect life here. It's manageable in the course of my lifetime," said Mike Marks, an outer Cape resident and founder of the tourism website Morebeach.com. "There's damage everywhere if you look, but the rate of sea-level rise is still very slow and incremental."
Devoted beach lovers will hold out as long as possible. Six years ago waves broke through a barrier island called North Beach near the Cape's elbow, creating a new inlet into Pleasant Bay. (The break was part of a longtime pattern of beach formation and retreat in that area, not an indicator of climate change, according to a report by the Provincetown Center for Coastal Studies.) Five summer cottages owned by the National Park Service were isolated on the newly-created island below the break. In 2012 the Park Service condemned and razed the cottages, saying that erosion on the island was accelerating and the buildings could collapse during storms.
Leaseholders hotly opposed the decision and argued that the Park Service was exaggerating the risk. Some said they would rather see the cottages washed away naturally than torn down.
"Everybody knew those cottages would probably be destroyed by storms in another five to 10 years. The resistance was just about how long they could hang on," Adams said. "People used to go out with a Jeep and hydraulic jacks and drag their houses back from the shore when waves got too close. But that was the old Cape. Those days are gone."
© Jennifer Weeks, 2013. All rights reserved
Photos and graphics (from top): Cottage for sale in Wellfleet, Mass. courtesy Atlantic Bay Sotheby's International Realty. Graphic displaying development change on Cape Cod from 1951 to 2005 by Woods Hole Research Center. Photos of sliding cliffs sign and erosion at Herring Cove Beach by Jennifer Weeks.
Jennifer Weeks is a freelance reporter based near Boston and a frequent contributor to the Daily Climate. DailyClimate.org is a foundation-funded news service covering climate change. Contact editor Douglas Fischer at dfischer [at] DailyClimate.org
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