- Background on Boston area topography and storm risks
- Summary of regional agency efforts to assess flood risk
- City of Cambridge climate adaptation resources
- City of Boston climate adaptation resources
- International Panel on Climate Change — 5th Assessment Report
- Prior Brownsberger legislation on storm-tide risks
Over the last few weeks, I’ve been trying to better understand the local flooding risks caused by the sea-level rise caused by climate change. (Of course, we should also continue to do all we can to control climate change).
It’s hard to know how much the seas are going to rise. First, no one knows how much the people of the world will be able to reduce carbon emissions. Second, even within a given emissions scenario, the uncertainties are considerable. For example, if we just assume continually growing emissions, the estimates of probable local sea level rise vary by a factor of two from 3.2 feet to 7.4 feet by 2100.
Much of Boston lies quite low, so these uncertainties matter. Given the huge uncertainties about long term sea level rise, local planners are mostly not looking past 2070. Within that horizon, the uncertainties are more manageable. In that time frame, it is clear that Boston will not be submerged like some low-lying islands in the Pacific; rather, what we face is a modestly increased risk of extreme storm flooding.
My senate district includes Belmont, Watertown and Boston along the Charles. These areas are either elevated or well-protected by the seawalls at the mouths of the Mystic and the Charles. They therefore face fairly limited new risks through 2070. Some coastal areas face much more immediate risks.
We all need to be concerned to protect our shared regional infrastructure — our tunnels, our transit system, our power grid, our water and sewer systems. If storms knock out critical infrastructure components, the losses go well beyond just the cost of repair. For example, if the central artery/tunnel or our subway tunnels were flooded and unusable for a few weeks or months, the regional economy could be damaged and take years to recover.
My sense from the recent studies is that many smaller projects have clear value in improving near and medium-term resiliency. Gaps in land barriers need to be filled, tunnel entrances enclosed, vent structures elevated.
To identify and implement those higher payback projects, we need to do two things: We need to push for the formal vulnerability analyses to continue. At the same time, we need to assure that each of the agencies that own infrastructure has the resources necessary to build and retain institutional knowledge of the particular assets they own. The engineers and operators who work outside every day are the ones who can most readily identify specific vulnerabilities.
It will remain a continuing priority for me as a legislator to assure the comprehensiveness of infrastructure vulnerability assessments and to support infrastructure agencies with the funding they need to maintain strong teams.
It will also remain a continuing priority for me to keep up with the climate science. As new results emerge, we may need to change our approach. The world’s big ice masses in Greenland and Antarctica are the wild cards. New understandings of how they are responding to warming may force upward revisions in our expectations for sea level rise. Changed expectations could give more urgency and credibility to the more ambitious defensive proposals, like a harbor barrier.
Finally, it will remain a continuing priority for me to keep talking about these issues. Citizens and business need to have access to the latest available understandings and make their own judgements about how they want to manage risks.