Glossary of Terms



Carbon dioxide (CO2)

The chemical compound carbon dioxide (also known by its shorthand CO2) is the primary greenhouse gas and driver of climate change. It is an integral part of life cycles on earth, produced through animal respiration (including human respiration) and absorbed by plants to fuel their growth, to name just two ways. Human activities are drastically altering the carbon cycle in many ways. Two of the most impactful are: one, by burning fossil fuels and adding more carbon dioxide into the atmosphere; and two, by affecting the ability of natural sinks (like forests) to remove carbon dioxide from the atmosphere.


Massachusetts State government including all the legislative, executive, and judicial branches that comprise the state government.


Emissions refer to greenhouse gases released into the air that are produced by numerous activities, including burning fossil fuels, industrial agriculture, and melting permafrost, to name a few. These gases cause heat to be trapped in the atmosphere, slowly increasing the Earth’s temperature over time.

Fossil Fuels

Fossil fuels are sources of non-renewable energy, formed from the remains of living organisms that were buried millions of years ago. Burning fossil fuels like coal and oil to produce energy is where most greenhouse gases originate. As the world has developed and demand for energy has grown, we have burned more fossil fuels, causing more greenhouse gases to be trapped in the atmosphere and air temperatures to rise.

Global average temperature

Global average temperature is a long-term look at the Earth’s temperature, usually over the course of 30 years, on land and sea. Because weather patterns vary, causing temperatures to be higher or lower than average from time to time due to factors like ocean processes, cloud variability, volcanic activity, and other natural cycles, scientists take a longer-term view in order to consider all the year-to-year changes.

Global warming vs climate change

Many people use these two terms interchangeably, but it is important to acknowledge the differences. Global warming is an increase in the Earth’s average surface temperature from human-made greenhouse gas emissions. On the other hand, climate change refers to the long-term changes in the Earth’s climate, or a region on Earth, and includes more than just the average surface temperature. For example, variations in the amount of snow, sea levels, and sea ice can all be consequences of climate change.

Greenhouse Gas

A greenhouse gas is a chemical compound found in the Earth’s atmosphere, such as carbon dioxide, methane, water vapor, and other human-made gases. These gases allow much of the solar radiation to enter the atmosphere, where the energy strikes the Earth and warms the surface. Some of this energy is reflected towards space as infrared radiation. A portion of this outgoing radiation bounces off the greenhouse gases, trapping the radiation in the atmosphere in the form of heat. The more greenhouse gas molecules there are in the atmosphere, the more heat is trapped, and the warmer it will become.

Greenhouse Gas Measurement

Greenhouse gas emissions are measured and reported in Metric Ton CO2 Equivalent (MT CO2e). But CO2 is by far the most prevalent, so other gases are equated to CO2 when discussing overall emissions – CO2e. “CO2e” simplifies analysis by converting the warming impacts of other greenhouse gases — like methane — into CO2 terms. According to the EPA, 1 metric ton of CO2e is produced by driving from San Francisco to Atlanta in an average passenger vehicle.


Methane is a chemical compound that is the main component of natural gas, a common fossil fuel source. Just like carbon dioxide, methane is a greenhouse gas that traps heat in the atmosphere. Methane accounts for about 10 percent of all US greenhouse gas emissions (using 2013 figures), second only to carbon dioxide. While methane does not stay in the atmosphere as long as carbon dioxide, it absorbs 84 times more heat, making it very harmful to the climate.


Mitigation refers to an action that will reduce or prevent greenhouse gas emissions, such as planting trees in order to absorb more CO2. It can also include developing and deploying new technologies, using renewable energies like wind and solar, or making older equipment more energy efficient.


Collectively all towns and cities in Massachusetts

Pre-Industrial Levels of Carbon Dioxide

Pre-industrial levels of carbon dioxide refer to carbon dioxide concentration in the atmosphere prior to the start of the Industrial Revolution. Scientists estimate these pre-industrial levels were about 280 PPM, well below where we are today.

Property owner

A resident or non-resident, in control of the investments and maintenance decisions for any type of structure.

Renewable energy

Renewable energy is energy that comes from naturally replenished resources, such as sunlight, wind, waves, and geothermal heat. By the end of 2014, renewables were estimated to make up almost 28% of the world’s power generating capacity, enough to supply almost 23% of global electricity. Because renewables do not produce the greenhouse gases driving climate change, shifting away from fossil fuels to renewables to power our lives will put us on the path to a safe, sustainable planet for future generations.


Any person who identifies their primary shelter in Westborough.

Sea-Level Rise

Sea-level rise as it relates to climate change is caused by two major factors. First, more water is released into the ocean as glaciers and land ice melts. Second, the ocean expands as ocean temperatures increase. Both consequences of climate change are accelerating sea-level rise around the world, putting millions of people who live in coastal communities at risk.


adjective for Massachusetts such as “state agency” or “state residents”.


[with initial capitalization] Town of Westborough municipal government


adjective for Westborough such as “town roads” or “town businesses”.

Weather vs Climate

Weather refers to atmospheric conditions in the short term, including changes in temperature, humidity, precipitation, cloudiness, brightness, wind, and visibility. While the weather is always changing, especially over the short term, climate is the average of weather patterns over a longer period (usually 30 or more years).