Skip to main content

Massachusetts Climate Change Projections


The Massachusetts Climate Change Projections - Statewide and for Major Drainage Basins:  Temperature, Precipitation, and Sea Level Rise Projections project was developed by NE CASC with funding by the Commonwealth of Massachusetts. In Sept. 2016 Governor Baker signed a Comprehensive Executive Order committing the administration to work across the state to plan and prepare for the impacts of climate change. The goal of this project was to develop down scaled projections for changes in temperature, precipitation, and sea level rise for the Commonwealth of Massachusetts. The Executive Office of Energy and Environmental Affairs has provided support for these projections to enable municipalities, industry, organizations, state government and others to utilize a standard, peer-reviewed set of climate change projections that show how the climate is likely to change in Massachusetts through the end of this century. 

Temperature and Precipitation
The down-scaled, or localized, temperature and precipitation projections are based on simulations from the latest generation of climate models from the International Panel on Climate Change and scenarios of future greenhouse gas emissions. The models were carefully selected from a larger ensemble of climate models based on their ability to provide reliable climate information for the Northeast U.S., while maintaining diversity in future projections that capture some of the inherent uncertainty in modeling climate variables like precipitation. Both annual and seasonal projections are available at the statewide and major drainage basin geographic scales.

Sea Level Rise
Future sea level projections are provided for the Massachusetts coastline at established tide gauge stations with long-term records at Boston Harbor, MA, Nantucket, MA, Woods Hole, MA, and Newport, RI. The projections are adjusted to each station’s mean sea level and converted to the North American Vertical Datum of 1988 (NAVD88). The sea level projections are based on a methodology which provides complete probability distributions for different scenarios of future greenhouse gas emissions. The methodology for developing these projections closely follows the approach utilized for the recent city of Boston’s sea level rise projections in 2016 and similar analyses for the states of California and New Jersey.

Hydrological Assessment
The flow of a stream represents an integrated basin response to climatic variables, especially precipitation and temperature. Changes over time in the seasonal flow of streams that drain unregulated basins with stable land use generally reflect changes in climatic variables and can be used as indicators of climate change.  This work concluded that March mean stream flows increased significantly over time, by 76 percent to 185 percent at the seven stream flow gaging stations with the longest continuous record in areas of New England.  May mean stream flows significantly decreased at 10 stations in northern or mountainous sections of Maine and New Hampshire, and May mean flows decreased by 9 to 46 percent at the seven stations with the longest continuous records. This aligns with the assessment by the Intergovernmental Panel on Climate Change that annual temperatures and precipitation in New England increased in the 20th century.