Cambridge, Massachusetts Climate Change Vulnerability Assessment - Part I
The City of Cambridge, Massachusetts completed a Climate Change Vulnerability Assessment (CCVA) which primarily focuses on the City’s vulnerabilities to increasing temperature and precipitation, while addressing risks from sea level rise and storm surge flooding through 2030. The CCVA report consists of a 36 page summary report and three supplemental technical reports. Cambridge also completed Part 2 of the CCVA which discusses sea level rise and coastal storm surge impacts projected for the area.
The assessment used climate projections that were generated specifically for Cambridge. The customized projections take into account the City’s location near the ocean, the urban heat island effect, and other local factors. The output from the projections provided temperature, humidity, and precipitation projections for Cambridge. The City chose three planning horizons for assessing vulnerability: present day, 2030, and 2070 - each using thirty-year averages for temperature and precipitation data. The assessment found that Cambridge is more vulnerable to increasing heat and precipitation-driven flooding in the near future than to sea level rise and coastal storm surges.
|Cambridge assessed social vulnerability to climate change in each of its census tracts by assigning scores for sensitivity and adaptive capacity. The sensitivity score took into account poverty, the population older than 65, and the population younger than 5. The adaptive capacity score considered poverty, low education levels, language isolation, and the number of elderly people living alone. Both scores were put into a matrix to produce the map below. The vulnerability assessment also considers flood exposure, hazardous material sites, and information about people of color.|
Six major critical infrastructure systems were studied:
- Critical Services
- Roadways and Bridges
These infrastructure assets are assessed for climate impact vulnerability for those most at risk from flooding and increased heat.
The future rainfall projections for Cambridge were used in hydrologic/hydraulic models to create the maps of projected flooding. The flooding maps help identify the neighborhoods, streets, and individual structures most at risk of flooding. The 100-year storm flood maps depict a larger at-risk area compared to the 10-year storm flood maps. However, while the 10-year storm flood covers a less extensive area, the flooding from this type of event is projected to be more likely and frequent for those areas affected (because it has a 10% chance of occurring every year).
Sea level rise and coastal storm surge scenarios demonstrate that Cambridge’s coastal storm surge protections will hold until at least 2030, but as sea level rises these protections could be surpassed.
The assessment also considers social vulnerability and identifies areas of the City with greater concentrations of at-risk residents. The project team worked closely with public health scientists, critical service providers, and social service professionals to develop proxy indicators from 2010 census data for the City’s populations vulnerable to increased heat and flooding.
The Priority Planning Areas Map (found in Figure 4) summarizes the most at-risk services and populations, with respect to climate change within the boundaries of Cambridge. The map clearly illustrates that risk from climate change, posed by flooding and increased heat, is not evenly distributed throughout the City - where Northern Cambridge and eastern Cambridge have relatively more physical and social vulnerability.
Potential economic effects from climate change were estimated using an economic activity model source. Preliminary findings indicate that a citywide disaster could impact nearly all of the City’s 128,000 jobs and result in a loss of nearly $43 million a day based on the City’s GRP.
The associated technical reports include:
- Climate Projections and Scenario Development
- Critical Assets and Community Resources
- Vulnerability and Risk Assessment Technical Reports - including:
•Ranking Reports for Critical Assets & Community Resources
•Climate Change Vulnerability Assessment for the Urban Forest in Cambridge
•Vulnerable Population Ranking Memorandum
•Public Health Assessment
•Economic Vulnerability Assessment
Publication Date: November 2015
- City of Cambridge, Massachusetts
- Air temperature
- Heat waves
- Precipitation changes
- Sea-level rise
- Water supply