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What are greenhouse gas emissions?

Greenhouse gasses are gasses that trap heat in the atmosphere much as a layer of glass or translucent plastic traps heat in a greenhouse used for growing plants.  The term greenhouse gas emissions typically refers to gasses that are released from anthropogenic (human-influenced) sources, such as the burning of fossil fuels.


What are the most common greenhouse gasses?

To understand how to reduce greenhouse gasses, we must first understand what they are and how they enter the atmosphere. 

Most Common Greenhouse Gasses

Carbon dioxide (CO2)

Carbon dioxide is emitted from the burning of fossil fuels for transportation, heating, energy generation, etc.

Methane (CH4)

Methane is not as abundant as CO2 in the atmosphere but, with a global warming potential approximately 30 times higher than that of CO2, it is much more potent. Some methane is naturally released by decaying vegetation and by the bacteria in wetlands and swamps. But since 1750, the amount in the earth’s atmosphere has doubled due to human activity, primarily due to the oil and gas industry, agriculture, and landfills.

Here’s how methane emissions occur:

OIL AND GAS INDUSTRY The fossil fuel industry generates a third of all methane emissions. The gas leaks from pumps, pipelines and wells as oil and natural gas are extracted and transported. There is also growing evidence that the decomposition of petroleum-based plastic discarded in landfills and in oceans is responsible for methane emissions. 

AGRICULTURE (especially livestock) As they digest their food, farm animals release methane (primarily in the form of burps, but also flatulence and manure).  According to the United Nations’ Food and Agriculture Organization, livestock — including cows, pigs, sheep and other animals — are responsible for about 14.5%of global greenhouse gas emissions, with cows the primary offenders.  There are currently an estimated 1.3 to 1.5 billion cows on the planet, and each animal releases an average of 30 to 50 gallons of methane gas per day.

LANDFILLS Methane is emitted from landfills as organic matter such as food waste, wood and paper decompose.

Nitrous oxide (N2O)

Nitrous oxide is emitted from agricultural practices (primarily chemical fertilizer use), the combustion of fossil fuels, solid waste, wastewater treatment systems and other industrial activities.

Fluorinated gasses (F-gasses)

The gasses in this category (including Hydrofluorocarbons - HFCs, Perfluorocarbons - PFCs,  Sulphur hexafluoride, or SF6, and others) are emitted from technological innovations such as refrigeration systems, LCD (Liquid Crystal Display) panels, certain types of solar panels, chemical lasers and electrical transmission systems during their lifetime, and also from industrial processes such as semiconductor manufacturing, aluminum production and magnesium production.


Renewable Energy

What are alternatives are there to fossil fuels? Renewable energy is energy derived from natural sources that are replenished at a higher rate than they are consumed. Sunlight and wind, for example, are such sources that are constantly being replenished. Renewable energy sources are plentiful and all around us. – United Nations, :What is Renewable Energy? 


Solar technologies convert sunlight into energy using photovoltaic panels, solar power is the cleanest and most abundant renewable energy source we have. – Office of Energy Efficiency and Renewable Energy:

1. Solar Energy

Community solar projects in Maine

Maine Public features 5 new community solar projects went online in recent weeks, delivering power to nearly 2,000 Mainers.

Municipal, nonprofit and school solar projects in Maine

Revision Energy installs solar for municipalities and non-profits. 

A Climate To Thrive, Mount Desert Island Solar Initiatives

ACTT received unanimous support for assisting the town of Bar Harbor to turn an abandoned gravel pit into a solar farm that will power every school and municipal facility. Other project include MDI High School going fully photovoltaic (solar) powered, and the first electric school bus in Maine.

My Maine Roadtrip to the Future 

This film features Rich Silkman, Grid Solar, who together, designed a micro-grid project for the Boothbay peninsula that cost 1/3 the estimated cost for CMP to run another powerline down the peninsula.

Community Solar in Western Maine

Center for an Ecology Based Economy is working on getting co-operative community solar to Western Maine

The Solarize Guidebook

This guidebook is intended to be a roadmap for project planners and solar advocates who want to create their own successful Solarize campaigns. It describes the key elements of the Solarize Portland campaigns and variations from projects across the country, along with lessons learned and planning templates.

Wind turns propeller-like blades of a turbine around a rotor, which spins a generator, which creates electricity. –

2. Wind Energy

Maine Offshore Wind Initiative

Launched in June 2019 by Governor Janet Mills, the Maine Offshore Wind Initiative aims to explore thoughtful development of floating offshore wind energy in the Gulf of Maine, while ensuring balance with our state’s maritime industries and environment.

NRCM | Offshore Wind in the Gulf of Maine

Bringing Maine-made offshore wind technology to the Gulf of Maine would create good-paying jobs and generate large amounts of clean energy to meet our climate goals, protect our environment, and help make us more energy independent.  

Maine Audubon Wind Power and Wildlife

As the push for renewable energy increases, Maine Audubon strives to understand the impact of wind power development on wildlife and habitat, and supports siting and operating of renewable wind energy in places and ways that avoid or minimize those impacts.

Advanced Structures and Composite Center

The University of Maine Advanced Structures and Composites Center (ASCC) is a world-leading, interdisciplinary center for research, education, and economic development encompassing material sciences, advanced manufacturing, and engineering of composites and structures.

Is small wind practical for you?

The Small Wind Guidebook helps homeowners, ranchers, and small business owners decide if wind energy will work for them.

Tidal energy is produced by the surge of ocean waters during the rise and fall of tides. – National Geographic:

3. Tidal Energy

Information on Maine Tidal Power

Read this information sheet on the Regulation of Tidal and Wave Energy Projects, created by the Maine Department of Environmental Protection.

Tidal Power in Downeast Maine

University of Maine's Center for Sustainable Solutions guide to tidal energy in Maine

DISCOVER MORE | Suggested topics


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