US Senate Committee Hears Expert on Costs of Adapting to Sea Level Rise and Storms in Boston, Coastal Cities

BOSTON - With sea level potentially rising to two feet by mid-century and six feet by the end of the century, Boston and surrounding cities are facing significant threats from flooding. 

In addition to Cape Cod, a large swath of coastal Massachusetts is particularly vulnerable, and it’s possible that damages there could amount to just under $35bn over this century if action is not taken.

There are several plans, or adaptation strategies, that may be used to defend the Bay State’s coast; they are not foolproof and are expensive, but they could bring down the overall cost of expected damages.

Paul Kirshen, Research Professor at the Department of Civil Engineering and Institute for the Study of Earth, Oceans, and Space at the University of New Hampshire, testified at a US Senate Committee on Homeland Security and Governmental Affairs hearing entitled “Extreme Weather Events: The Costs of Not Being Prepared” last Wednesday.

Based on his 15 years of research and consulting experience concerning the impacts of climate change in New England, Kirshen was there to talk about the long-term costs of preparing ourselves for the threats of sea level rise and storm surges.

According to Kirshen’s written testimony, provided to Open Media Boston, there are four possible approaches for dealing with these potentially devastating threats.

Those approaches include: taking no action and rebuilding after each damaging event, such as flooding caused by a storm; building protective structures, such as seawalls to defend against coastal flooding; accommodating ourselves with these expected dangers, but trying to lessen the negative effects through flood-proofing, flood evacuation, elevating buildings, and purchasing insurance; and finally, retreating from floodplains.

Kirshen’s research estimates the costs to four coastal zones: an urban zone, including Boston and Quincy; another urban zone, including Winthrop, Revere, and Chelsea; a suburban zone stretching north to Rockport; and another suburban zone reaching down to Duxbury.

The research estimates that at just over 3ft (1m) of sea level rise, Boston and Quincy could see $14.9bn in damages by the end of this century if no action is taken.

Potential action that could be taken to defend the two cities against the growing threat would cost $400m, but it would still result in residual damages of $2bn, because no adaptation plan is foolproof.

At around 2ft (.6m) of sea level rise, it’s estimated that there could be $7.8bn in damages in Boston and Quincy, with adaptation costs again amounting to $400m, and with residual damages costing $2.2bn.

Ironically, the residual damages are slightly higher if sea level rises to only around 2ft, because the research assumes that adaptation actions would be taken later in the century with adaptation effort being tied to the amount of sea level rise.

Combining the three other zones, the research estimates that at just over 3ft (1m) of sea level rise, the damage could cost as much as $19.7bn during this century.

The combined cost of adaptation is estimated to be $1.4bn, and the residual damages could cost $3.6bn.

Again combining these three zones, the research estimates that at around 2ft (.6m) of sea level rise, the damage is estimated to be as much as $11.3bn.

The combined cost of adaptation could be $1.1bn, and the residual damages are estimated to cost $2.7bn.

Kirshen’s testimony concludes, “In none of the scenarios is taking No Action the more reasonable action in terms of costs.” (Emphasis in original)

The testimony explains that figures were calculated using a simulation to determine the “total damages from surge flooding to residential, commercial and industrial buildings over the next 100 years assuming sea level rises … of both 0.6 m (approximately 2 feet) and 1.0 m (just over 3 feet) with and without adaptation being taken.”

At the time of the research in the late 1990s, these estimates of sea level rise “were considered plausible ranges,” but now the US National Climate Assessment “considers both to be at the low end of the plausible range in 2100,” and as a result the cost of damages due to sea level rise may be underestimated, according to the testimony.

In a phone interview with Open Media Boston, Kirshen explained that based on figures produced by the National Oceanic and Atmospheric Administration, “very approximately” we’ll see “one to two feet of sea level rise by mid-century, and three to six feet of sea level rise by the end of the century.”

Though research by the Intergovernmental Panel on Climate Change has estimated a smaller increase in sea level rise, Kirshen explained, “we use three to six still, because six feet is generally accepted as the maximum amount of sea level rise we might find by the end of the century.”

According to the testimony, the results of the simulation found that “a protection approach is favored in heavily urbanized” zones “to protect valuable, densely built-up areas,” and “Flood proofing, elevating buildings, and other accommodation actions are reasonable for less developed areas.”

The testimony says that at the time of research, “less data were available for these types of studies than exist now … but the results are still representative of the costs. “While in reality in every zone there would be a mix of adaptation actions taken in different locations and time periods … we assumed that in each zone only one adaptation action could be taken,” it continues.

The testimony also says that the research “may actually underestimate the actual damage costs because these types of costs are not included in the analyses; human deaths and injury; damages to ecosystems … and indirect costs such as lost employment and business activities, and community displacement and disruption.”

Though concerns about major storms hitting Boston have been heightened since Hurricane Sandy hit parts of New York and New Jersey in October 2012, Kirshen said during the interview that it “was an extremely rare event, it was like a three to 500-year storm … so given that probability it’s very unlikely we would be struck by a storm of Sandy’s magnitude any time soon.

“We’re unlikely to be struck by a storm of that magnitude now, but with sea level rise, that storm could become a 100-year storm, or more frequent, it depends on how much sea level rise we have,” he continues, “but it’s very unlikely in the next couple of decades.”

Though he doesn’t believe there’s a high chance of a ‘super storm’ such as Hurricane Sandy hitting the Boston area in the two decades, Kirshen says that the people in charge of Boston and its infrastructure would “want to be prepared for an event like that.”

In regard to the existing level of preparedness, Kirshen says that “the various institutions – state and city institutions – that work in Boston, are all pretty much about to, or are actively carrying out vulnerability assessments to climate change … and the next step of those studies is adaptation studies.”

He says, “I think the city leadership on this is good, and I think it’s well respected by other cities in the United States as being ahead of the curve.”

Commenting on the recent $50m state investment in climate change preparedness initiatives by Gov. Deval Patrick, Kirshen said that it’s “not enough, but it’s a start, and that’s what you need.”

He also says that the necessary investment is “not all going to be government money, it’s going to require some private investment as well.”

In regard to the timeframe in which the Boston, and other coastal cities, needs to begin adaptation, he says that measures should be in place before “we get flooded at every single high tide.”

He says that given that the low probability of getting hit by a major coastal storm that would cause a large amount of damage, “I think we have a couple of decades, but only a couple of decades to get some stuff in place.”