Climate Change in Massachusetts and Its Impacts

Learn how the Commonwealth is being affected by climate change.


Climate change is among the greatest environmental challenges of this generation. It can have potentially profound effects on:

  • the economy
  • public health
  • water resources
  • infrastructure
  • coastal resources
  • energy demand
  • natural resources
  • recreation

The Commonwealth of Massachusetts is committed to doing its part to mitigate and adapt to this challenge, recognizing the necessity of engaging in adaptation planning today by taking a close look at strategies that could help the state become more resilient and ready to adapt to climate change as it occurs.

Section 9 of The Global Warming Solutions Act, passed by the Massachusetts Legislature and signed in 2008, directed the Secretary of Energy and Environmental Affairs (EEA) to convene an advisory committee to develop a report, analyzing strategies for adapting to the predicted changes in climate. Below are some of the Climate Change Advisory Committee's key findings regarding the changing Massachusetts climate.

How is the climate changing in Massachusetts?

Weather station records of the United States Historical Climatology Network indicate that the Northeast has been warming at an average rate of nearly 0.26°C per decade since 1970, and winter temperatures have been rising even faster at a rate of over 0.7°C per decade. Other observations indicate that extreme heat days are on the rise - we now experience about 5 to 20 days of temperature over 90°F each year. These higher ambient temperatures have resulted in a 1.3°C increase in annual average sea surface temperature between 1970 and 2002.

Precipitation patterns have also changed. In Massachusetts, precipitation data that go back nearly 200 years show a slight decrease in annual precipitation. However, a more recent 50-year view reveals an increase in total precipitation by approximately 10%. Furthermore, in the past few decades, more of this precipitation has been falling during winter in the form of rain. There is also evidence of a strong increase in extreme precipitation events (>50 mm of rain per event) since the 1970s in northern coastal New England, and in eastern Massachusetts between 1949 and 2002.

Being a coastal state, Massachusetts is affected by sea level rise. From 1921 to 2006, relative sea level has risen 2.6 millimeters annually - an increase of approximately 26 centimeters per century.

What are the predictions for Massachusetts and New England?

Temperatures are predicted to increase by 2.1° to 2.9°C by mid-century, and by 2.9° to 5.3°C by the end of the century, with greater increases in winter compared to summer. The frequency with which heat waves (three or more consecutive 90°F days) occur are expected to increase. By late-century, many Northeastern cities can expect 60 or more days per year over 32°C under the higher-emissions scenario (defined by the IPCC as a fossil fuel intensive world when the atmospheric CO 2 concentration is 970 ppm; today the CO 2 concentration is 380 ppm), or at least 30 such days if conservation and renewable energy efforts are successful.

By mid-century, sea surface temperature could increase by 1.7°C and, by the end of the century, by up to 3.3 to 4.4°C. Predictions of sea level rise are variable. By 2100, sea level rise in Massachusetts could range from 29 cm (if the current rate of sea level rise persists) to 201 cm (depending on the extent of global warming).

New England is expected to experience changes in the amount, frequency, and timing of precipitation.

  • By the end of the century, under the high-emissions scenario, annual precipitation is expected to increase by 14%, with a slight decrease in the summer, and a 30% increase in the winter. Additionally, it is predicted that most of the winter precipitation will be in the form of rain rather than snow.
  • Scientists predict an 8% increase in extreme precipitation events in the northeastern U.S. by mid-century, and up to a 13% increase by 2100.

Because of these heavy precipitation events, flooding could become a problem.

How will the changes in climate impact Massachusetts?

Changes in the climate can have subtle as well as devastating effects on humans, human infrastructure, and natural systems. An increase in temperature can cause:

  • increased virulence of viruses, insects, and pests
  • decimation of sensitive crops and plants
  • a decline in air quality that can increase asthma and other human health effects
  • impacts on the built environment

Heat waves are predicted to be of particular concern and could have broad implications for:

  • public health
  • infrastructure
  • government capacities
  • native plants
  • agricultural crop

It is likely that habitat boundaries of certain species may shift. Certain native species will likely move northward toward cooler waters, and more species from southern latitudes will appear in Massachusetts and nearby waters.

Increased temperatures will have broad effects across estuarine and marine habitats and the ecosystem services they support; impacts to marine species will influence the state's fishing industry-both recreational and commercial. As an example, cod require habitat with an average annual bottom temperature below 12°C. This species will likely disappear from the waters south of Cape Cod by late-century under the higher-emissions scenario.

Increases in sea level rise can have severe consequences for both natural and manmade systems, including:

  • an increase in the height of storm surges and associated coastal flooding frequencies
  • permanently inundated low-lying coastal areas
  • amplifying shoreline erosion
  • threaten barrier beach and dune systems

Extensive development and infrastructure, both public and private, would be affected by increased flooding. Higher sea levels will also intrude on productive aquifers situated in permeable sands and gravels, and drinking water could be contaminated due to saltwater intrusion.

Change in precipitation will have significant effects on:

  • the amount of snow cover
  • winter recreation
  • spring snow melt
  • peak stream flows
  • water supply
  • aquifer recharge
  • water quality

Large areas of the Northeast are projected to lose more than 1/4 and up to 1/2 of their snow-covered days toward the end of the century in the high-emissions scenario as a result of increased ambient temperature in February and March.

The predicted changes in the amount, frequency, and timing of precipitation, and the shift toward more rainy and icy winters would have significant implications for winter recreation such as skiing and snowmobiling, and could compromise water supplies and water availability for fish and various habitats. More winter rain is expected to drive more high-flow and flooding events during the winter, earlier peak flows in the spring, and extended low-flow periods in the summer months.

These changes in hydrologic cycles would have profound impacts on water resources, including increased flooding and polluted overflows from stormwater and wastewater systems during high periods of flow, and increased stress on surface and ground drinking water sources during periods of drought and low flow. Increased intensity of precipitation can:

  • cause increased flooding
  • put humans and their property at risk
  • ruin crops
  • create public health concerns from sewage overflows and hazardous waste leaks.