Sink or Swim: How Carbon Cuts Will Affect Coastal Cities

A Q&A with two Boston city planners who have to consider sea level rise projections, including a new one based on the world's emissions.

An interactive map by Climate Central shows sea level rise based on emissions levels
The nonprofit Climate Central created interactive maps showing sea level rise based on global emissions levels. Credit: Climate Central

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Even if the Paris climate talks result in unprecedented carbon cuts, the greenhouse gas emissions already present in the atmosphere will lock in enough long-term warming to flood large areas of major U.S. cities, according to interactive maps created by Climate Central, a nonprofit research and news organization.

The maps, which are based on peer-reviewed research, show the extent of sea level rise that would result from scenarios ranging from unchecked carbon pollution to extreme emissions cuts. Around Boston, for example, cultural icons and crucial infrastructure—including Fenway Park, Symphony Hall, Logan International Airport and parts of Harvard University—will be flooded in 2200 or beyond even if the global temperature rise is limited to 2 degrees Celsius by 2100. That’s the internationally agreed upon goal negotiators hope to achieve this December in Paris, but current emissions reduction pledges fall short of what’s needed.

The situation is particularly grim for low-lying cities such as New Orleans, Fort Lauderdale and Miami. All three metropolitan areas would be inundated if warming tops 2 degrees C. 

The interactive nature of the maps allows users to envision the long-term consequences of today’s actions. As noted on the Climate Central website, “These maps pose this question: which legacy will we choose?”

InsideClimate News spoke with two climate adaptation experts in Boston about what the projections mean for city planning: Carl Spector, director of climate and environmental planning for the City of Boston, and his colleague Mia Goldwasser, a climate preparedness fellow who works on climate adaptation planning. Boston is a member of C40, a global compact of cities committed to tackling climate change. Last year, the city pledged to reduce its greenhouse gas emissions 25 percent by 2020.

The interview has been edited for length and clarity.

InsideClimate News: What was your reaction to the Climate Central map of Boston?

Spector: Based on my quick look at it, it looked roughly similar to “bathtub models” that have previously been run for Boston regarding climate change. So it’s a story that we’ve been telling here in Boston for several years.

Goldwasser: I think that when you see these kinds of maps, they’re definitely scary to look at. But what’s more important is that they start a conversation of what these impacts could look like in Boston, what does it mean for the type of action we can take, and also what it means for the level of greenhouse gas reductions that we still want to do to make sure that this type of thing doesn’t actually happen.

ICN: How does Boston plan to deal with sea level rise?

Spector: In 2007, then-Mayor Thomas Menino issued an executive order on climate action. It directed all departments in the city to start including climate change projections in their long-range planning and in their permit reviews.

For example, two years ago we incorporated a formal requirement that proposed projects overseen by the Boston Redevelopment Authority [the city’s urban planning and economic development agency] include analysis of climate change, and the proposals had to give a description of what steps the projects were taking to reduce their vulnerability.

Goldwasser: The mayor [Marty Walsh] chairs a Metro Mayors Task Force on climate preparedness, which includes Boston and the 13 towns that surround it. So this is the major effort to … look at how impacts can be dealt with at the regional scale, and not just within the artificial borders of Boston.

ICN: Can you give me an example of the type of climate planning used for projects created under the Boston Redevelopment Authority?

Spector: At Spaulding Rehabilitation Hospital [which opened in 2013 at the Boston Navy Yard], they raised the buildings based on their analysis of climate change. They moved all of their critical equipment to higher floors. They landscaped the site in order to break the power of waves that could be produced.

We’ve seen examples of buildings that are putting in place the capability of putting up an aquafence, that can protect the building up to four feet of flooding around that site. We’ve seen property owners that are talking about making sure electrical equipment is not in a place that could be flooded and things like that.

ICN: The Climate Central map projects flooding that will occur in 2200 or beyond. How do you plan for something that far ahead?

Spector: I think an important point … is the opportunity and necessity to think in terms of planning steps. Taking a step to protect yourself from the climate change effect likely to occur in the next 20-30 years can [be used] to set the stage for the next step, [which] will give you the next 30 years, or the next 50 years.

We don’t need to protect Boston today for the threat that will be here 200 years from today. But we are building buildings and we are building infrastructure that will easily be around 30 years from now or 50 years from now … We can think about the natural turnover and recognize that we can use those cycles to ensure that we are keeping up with the changes as they occur.

Goldwasser: Even though sea level rise is a climate impact that’s going to be felt over the longer term … it’s only one part of this conversation about climate change. We’re also looking at flooding and storm impacts that could happen this year or next year. We’re looking at extreme heat impacts that could happen every summer. It’s not all looking to the end of the century.

ICN: Boston’s greenhouse gas emissions are a tiny fraction of global emissions. Even if the city goes carbon-neutral, it won’t have a big impact on future sea level rise projections. How do you deal with that in your future planning?

Goldwasser: Well, it’s true on one level that Boston itself can only have a certain impact, but Boston is part of a network of international cities that are working on reducing their carbon emissions. And cities are really taking the lead in this field. Boston, as part of a network, can and will have a substantial effect on our greenhouse gas emissions.