In 2007, Boston Mayor Thomas M. Menino issued an executive order that committed the City to reducing its annual GHG emissions by 80% below 1990 levels by 2050.¹ This set in motion an ongoing stream of research, community engagement, and policies to reduce GHG emissions by improving energy efficiency and shifting to cleaner fuels and electricity. In 2016, Mayor Martin J. Walsh deepened the City’s commitment by setting a goal of carbon neutrality (zero net emissions) by 2050.² In 2019, the City released the latest in its series of Climate Action Plan updates that detailed progress to date and set new goals.³

Complete decarbonization is a formidable challenge because Boston, like every other major city, runs on fossil fuels. About three-quarters of total energy use in the city comes from oil and natural gas. Refined oil products power private vehicles, freight transport, and public transportation, and also heat homes in the winter. Natural gas is used to heat buildings and hot water and also to generate electricity in the New England power grid.

The types of energy used to generate electricity in the New England grid are critical ingredients affecting the capacity of the city to reach zero GHG emissions for two reasons. First, grid operators, not city officials, determine what energy sources are deployed for generation. Second, about one-quarter of the city’s energy use is in the form of electricity. This share will grow steadily in the future as electric vehicles, heat pumps, and electric boilers replace their fossil fuel counterparts. Natural gas currently generates about 45% of the region’s electricity, although the Massachusetts Clean Energy Standard is steadily reducing the carbon intensity of electricity that the city purchases. Boston cannot reach its emission targets without this decarbonization of the regional grid.

The most recent snapshot of Boston’s GHG emissions drives home these points. Buildings are responsible for more than two-thirds of total emissions. Electricity and natural gas dominate energy use in buildings while transportation services are dominated by personal and commercial vehicles, and to a lesser extent by public transportation, where oil dominates. Decarbonization requires that natural gas be eliminated largely through the use of heat pumps and electric boilers in buildings and that electricity is generated by low-carbon sources such as nuclear, wind, solar, hydropower, etc. Vehicles and trains must be electrified, and trips need to shift to public transportation, walking, and biking.

So, let’s return to the question posed at the outset: is Boston on track to be carbon neutral by 2050? The good news is that emissions exhibit a downward trend. In 2019 emissions were about 21% lower than they were in 2005. The City has reduced emissions from its operations by a third since 2005, and a shift away from heating oil to natural gas and improved building energy efficiency have also reduced emissions. But the single most important factor lies outside the city: the regional electricity grid has reduced its carbon intensity by 69% from 2005 to 2019.

The City is frank about the challenge of meeting its ambitious targets in its 2021 Climate Action Report:

The City has prioritized emissions reductions that simultaneously improve outcomes for the city’s socially vulnerable populations. This cannot be done by the city government alone. All Bostonians must embrace the idea that every person should have access to safe, affordable, and clean energy, and have an active voice in how decisions are made regarding the transformation of the city’s energy system.

1 An Order Relative to Climate Action in Boston, Office of the Mayor, City of Boston, April 13 2007 Link

2 Metro Mayors Climate Mitigation Commitment, 2016, Link

3 City of Boston 2019 Climate Action Plan Update, October 2019, Link

4 City of Boston Climate Action, Fiscal Year 2021 Report, Link