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The Colonel John W. Pershing Annual Military History Lecture, Wednesday, March 26, 4 p.m., SMG Auditorium

Week of 21 March 2003· Vol. VI, No. 25

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Global warming = rising sea levels, more storms
Future extreme weather could cause billions in damage to region

By Brian Fitzgerald

Flooding in October 1996 caused the Emerald Necklace’s Leverett Pond in Brookline to overflow its banks. Photo courtesy of the Massachusetts Emergency Management Agency


Flooding in October 1996 caused the Emerald Necklace’s Leverett Pond in Brookline to overflow its banks. Photo courtesy of the Massachusetts Emergency Management Agency


On October 21, 1996, 10.8 inches of rain — over a month’s worth — fell on Boston in one day. The precipitation, “more than what Noah saw,” commented an official from the Federal Emergency Management Agency (FEMA), caused the city’s Muddy River to overflow and run down the MBTA D Line into the subway at the Longwood station tunnel.

Overnight, the water level in the underground Green Line stations rose higher and higher — at the Kenmore station, all the way up to the ticket booth. Service was seriously interrupted for weeks and the damage was estimated at $60 million for the MBTA alone.

So, six and a half years later, when two BU geographers sought to demonstrate the consequences of climate variability on the city of Boston, they looked into the past to paint a picture of the future. At a conference in Denver last month, they presented slides of the flooded Longwood and Kenmore stations.

February’s annual meeting of the American Association for the Advancement of Science provided the perfect opportunity for a team of civil engineering and geography professors and graduate students from BU, Tufts, and the University of Maryland to discuss the impact of climate change on the Boston area. Global warming is expected to result in the rise of sea levels, and cause more extreme weather events, including floods and heat waves. The team’s research was funded by a $900,000 grant from the Environmental Protection Agency to study how climate change will affect the critical services and systems that make up the infrastructure in Boston and 100 surrounding communities. The researchers examined local flood data, the impact of rising sea levels, and the continuing construction of buildings along Boston’s North Shore and South Shore.

Their research shows that over the next century, damage to residential, commercial, and industrial buildings and their contents in Boston and nearby communities (an area stretching from Ipswich to Duxbury) could exceed $20 billion, depending on how municipalities respond to the consequent strains on their infrastructure. Costs could run as high as $94 billion, if weather conditions are more severe than expected.

“And when we consider the damage to infrastructure, we tend to think about it in terms of how much money it takes to rebuild it,” says William Anderson, a CAS geography professor. “But what’s also important to remember are the related costs to the public. The commuters who had to take shuttle buses after the 1996 storm were inconvenienced for a long time.” He says that it’s also necessary to take into account the work hours lost to traffic jams caused by buses bringing T customers to Green Line stops. This practice continued at intervals for over a year, until the “drowned” signal system was replaced by temporary signals. There were even further delays when a permanent system was installed.

In addition, the storm canceled the Head of the Charles rowing competition for the first time, flooded the Museum of Fine Arts, cut power in some areas, and forced cancellations of classes, workdays, and sporting events.

Recurring floods

When the BU researchers wanted to use another example of an extreme storm that paralyzed the area, they didn’t have to look very far. A deluge in June 1998 wasn’t of biblical proportions, but was serious enough to cause sewer overflows in Arlington, Cambridge, Canton, Medford, Newton, Norwood, Roslindale, Weymouth, and Winchester. They showed a slide of a flooded Willow Street in Roslindale, an area that is still recovering from the 1996 storm. Then it happened again: four months later about 300 homes and businesses in the South End were inundated with several feet of water and sewage. “We expect to see much more of these storms because of global warming,” says Pablo Suarez (GRS’05), a doctoral candidate in the department of geography and a research assistant at the GRS Center for Energy and Environmental Studies.

Most scientists say that burning oil and coal has led to the buildup of carbon dioxide in the atmosphere, which acts like a greenhouse roof, trapping heat on the earth’s surface. They also assert that global warming will result in more frequent and more intense storms, along with sea levels higher by about a foot in the next century because of melting glaciers and polar ice caps and thermal expansion of the ocean.

As part of efforts to protect life and property from flooding, FEMA has mapped out a “100-year floodplain” throughout the country, estimating the amount of coastal area that would be flooded by a storm likely to be so substantial that it occurs only an average of once every 100 years. It also mapped out a 500-year floodplain. “Because of rising sea levels, the same size wave that normally would swamp the 100-year floodplain in Boston will soon become high enough to overtake the 500-year floodplain,” says Paul Kirshen, a civil and environmental engineering research professor at Tufts. “Sea level rise will have a drastic impact on metropolitan Boston and other similar coastal cities if steps aren’t taken to address this issue.”

The researchers presented three possible scenarios of how Boston could respond to the change in sea level, and estimated both the cost of the response and the cost of repairing storm damage: the “Ride-It-Out” scenario, the “Build-Your-Way-Out” approach, and the “Green” option. The first would mean that over the next century, area cities and towns would continue developing in flood plains as it does now. “Riding it out, not doing anything extraordinary until we are faced with a crisis, would make additional infrastructure vulnerable,” says Anderson. Municipalities would repair storm damage as it occurs to return buildings to their original condition, which would cost $20 billion. The size of the areas flooded will more than triple over the next 100 years in this scenario. If Boston properties are damaged by more storms than the team estimates, the total property and emergency costs could reach $94 billion.

The Build-Your-Way-Out option would also allow the current development to continue without flood-proofing buildings, but would mean, says Anderson, that after a second storm at the level of a 100-year storm, “Boston would construct hurricane barriers and seawalls to protect coastal development.” Damages from this scenario would be “only” $5.9 billion over the next 100 years. However, construction of the necessary structures, with the additional costs of building dams and drainage systems, could cost up to $3.5 billion, and maintenance costs will be high.

A sensible scenario

The Green approach, Anderson says, “is a planned adaptation strategy that would be much better for the environment.” All new development in the 100-year and 500-year floodplains would be required to be totally flood-proof, along with currently existing homes and commercial and industrial buildings before being sold. Retrofitting homes would cost between $3,500 and $17,000 each. The Green alternative calls for spending $1.8 billion for flood-proofing, but damages would decrease to $4.7 billion.

“The Green scenario would require more political awareness, and that will be difficult to attain,” says Suarez. Anderson agrees. “The idea of restricting the activities of developers will be met with resistance,” he says. “Some policy-makers are generally only concerned with the short-term horizon.”

Kirshen says that it is imperative that governments in the metropolitan Boston area deal with the issue of the rising sea level and its impact on coastal development as soon as possible. “It would be in the region’s best interest to take this threat very seriously,” he says. “As Ben Franklin once said, ‘An ounce of prevention is worth a pound of cure.’ ”


21 March 2003
Boston University
Office of University Relations