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a.d. 2100: from Beantown to Water World?
Geography profs: storm flooding to devastate Boston as globe warms
By Brian Fitzgerald
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BU researchers who worked on a global warming study commissioned by the Environmental Protection Agency: T. R. Lakshmanan (left) and William Anderson (right), CAS geography professors, and doctoral candidate Pablo Suarez (GRS’05). Photo by Vernon Doucette |
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Anyone up for a gondola ride through the historic Faneuil Hall Canal?
Boston has been called the Athens of America because of its intellectual and cultural life, but by the end of this century, a heavy storm could make the city’s waterfront, financial district, and much of the Back Bay at times resemble Venice, according to a federally funded global warming study conducted by a team of researchers at BU, Tufts, and the University of Maryland.
The five-year, $1 million study, commissioned by the Environmental Protection Agency, revealed that climate change could produce a storm surge that would paralyze Boston’s infrastructure. Global warming, which increases ocean volume by melting polar ice caps and glaciers, could cause the sea level to rise more than three feet by 2100, engulfing low-lying areas of the city with water during a severe downpour, largely because ocean water would be pushed over the top of the Charles River Dam.
Even the scientists’ conservative estimate of a two-foot rise in the sea level would have devastating effects, says William Anderson, a CAS geography professor, who worked on the study. “Most people wouldn’t think that a two-foot rise in the sea level would make that much of a difference,” he says. “But if the timing is right, like the Blizzard of ’78 — which hit during high tide, and it was one of the highest tides of the month — the flooding would be incredibly extensive.”
The Blizzard of ’78, which caused seas to crest 16 feet above normal from Cape Ann to Duxbury, “created enough damage across coastal Massachusetts to cost $550 million in today’s dollars,” says Paul Kirshen, a Tufts civil and environmental engineering research professor, who led the team. “Because of the rising sea level and increased waterfront development, a storm of that magnitude would cause far more damage if it occurred today.”
The study, Climate’s Long-term Impacts on Metro Boston (CLIMB), estimates a whopping price tag of $94 billion for the Boston metropolitan area for large storms and other anticipated impacts of global warming in the next 100 years.
Scientists believe that burning fossil fuels has led to the buildup of carbon dioxide in the atmosphere, which acts like a greenhouse roof, trapping heat on the Earth’s surface and resulting in warmer weather and bigger storms. Boston could face at least 30 days of temperatures above 90 degrees annually, more than double the current number. The higher temperatures and extreme weather events from this phenomenon, according to the study, would also pose a health threat because of the respiratory effects of air pollution and more deaths from heat stroke — mortality rates tend to rise in Boston when temperatures exceed 90.
Commerce would also be hindered because trucks would be unable to get through flooded roads, and traffic delays could cause motorists to spend an estimated 80 percent more time on the roads. “Aside from flood damage and transportation delays, other disruptions of economic activity with high societal costs can result from electrical failures caused by flooding in certain locations,” says T. R. Lakshmanan, a CAS geography professor and director of the Center for Transportation Studies and a CLIMB researcher.
The researchers concluded that the most cost-effective approach to mitigating the damage would be to floodproof buildings and infrastructure now, rather than to choose a reactive “build-your-way-out approach.” This approach would require constructing hurricane barriers and seawalls to protect coastal development following another “100-year storm” — a freak storm whose chance of occurring during any given year is 1 percent. Over a 30-year period, there is a 26 percent chance of such an event.
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CLIMB’s computerized projection of an extreme coastal storm surge by the end of the century shows flooding in much of Boston’s downtown waterfront and financial district. Image courtesy of the National Environmental Trust |
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Upgrading infrastructure is costly, but the third approach, which the team dubbed “ride-it-out,” will end up being more expensive in the long run. Under this scenario, cities and towns continue to build without floodproofing measures on the coast, and then repair storm damage as it occurs. “Limiting development on the coast and river valleys is another way to address the potential problems,” says Anderson. “I think at the very least a strategy to protect cities and towns from flooding should include building seawalls. We’re encouraging people to think about the usefulness of preparing for these events before they happen.”
The study confirmed some of the researchers’ worst fears about global warming’s impact, but “it wasn’t all doom and gloom,” says Anderson. “I don’t think any of us were particularly surprised with the results. In some cases it was worse than we thought it would be, in some cases it was not as bad. We found that there would be a problem in the towns that don’t get their water from the Massachusetts Water Resource Authority — people who depend on their own wells and other water supplies would be in trouble, but there is enough extra capacity in the Quabbin-Wachusett reservoir system for those communities to draw upon. We found that no crisis is imminent as far as the water supply was concerned. The big issue will be coastal flooding and the flooding of the Charles River Basin.”
In fact, CLIMB’s computerized projection of extreme flooding shows the city’s Public Garden and Charles Street completely under water. In that scenario, one of the famous Swan Boats in the Public Garden lagoon could be paddled across Beacon Street, Storrow Drive, and the swollen river — all the way to Harvard Square.
Even areas west of the Back Bay would be affected. Lakshmanan points out that Kenmore Square and the nearby Muddy River would be inundated with water. A downpour in October 1996, for example, caused the Muddy River to overflow and flood the MBTA Green Line tunnels. The water level, at its highest, went all the way up to the ticket booth at Kenmore Station. Service was interrupted for weeks.
Of course, this Venice-like state wouldn’t be permanent. But Anderson and his colleagues are hoping that the probability of days and weeks of watery disruption — depending on the severity of the storms — will make politicians and other policy makers in Massachusetts take notice of their study.
“It is up to governments in the metropolitan Boston area to decide to deal with the issue,” says Kirshen. “But it would be in the region’s best interest to take this threat very seriously.”
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March 2005
Boston University
Office of University Relations