* Basic Terms *

Climate Change

Climate change refers to a global increase in temperature compared to preindustrial times. The increase was, and is still, caused by burning fossil fuels.  Burning fuels releases heat-trapping greenhouse gases (GHGs).  These gases warm up the atmosphere leading to extreme weather, rising sea levels and widespread impacts on ecosystems, health and economies worldwide.

1.5 Degrees

To prevent worsening and potentially irreversible effects of climate change, the world’s average temperature should not exceed the temperature of preindustrial times by more than 1.5 degrees Celsius.

Comment: The UN Environment Programme (UNEP) report states that within the next decade, global temperatures will likely exceed 1.5°C above pre-industrial levels. 

Carbon Dioxide

Carbon Dioxide (CO2) is used by trees and other plants during photosynthesis. The gas is released when we burn fossil fuels.

Fossil Fuels

Coal, oil, and gas are the three main types. Burning fossil fuels releases CO2. 

Methane

Methane is the greenhouse gas with the most potent heat(hyphen)trapping power for the first 20 years of its life in the atmosphere. 

“Natural” Gas vs. Methane

“Natural” gas is more accurately described as “fossil gas”.  “Natural gas” is the term used for a mixture we extract from the ground.  This mixture also contains other fossil gases and some non-fossil gases, such as CO2 and water.

Methane is a powerful greenhouse gas released when we extract all fossil fuels (“natural” gas, oil and coal). But it is also the main component of “natural gas”, which is often 90 per cent methane. 

Liquified Natural Gas (LNG)

LNG is “natural” gas in a liquid state. “Natural” gas becomes liquid when cooled to a temperature of around -160°C, making it easier to store and transport.

Comment: A large amount of energy is required to liquefy “natural” gas.  Building pipelines to carry LNG to ship abroad is highly controversial.   

Fracking

Fracking is a technique to blast a mixture of water, chemicals and sand into a well to break apart the rock formations and release previously inaccessible oil and natural gas deposits.  Fracking uses large amounts of fresh water. 

Comment: There are concerns about drinking water contamination, fracking-triggered earthquakes and impacts on the landscape.

Greenhouse Gases (GHGs)

These are gases that absorb and trap heat in the atmosphere. The main GHGs are carbon dioxide, methane, nitrous oxide and water vapour.  They cause the planet to heat up.

350 Parts Per Million

This is the safe concentration of carbon dioxide in the atmosphere.

Net Zero and Zero

We reach net zero when the amount of greenhouse gas we produce is no more than the amount taken away.

Zero carbon means no carbon is given off at all.  This is only possible with total reliance on renewable energy.

Renewable Energy

Renewable energy comes from natural sources that are renewed faster than they are consumed. That includes solar, wind, geothermal, hydropower and ocean resources.

“Clean” Energy

Governments include nuclear energy as “clean” energy along with hydrogen. 

Comment: The problem of nuclear waste has never been resolved; and there are several forms of hydrogen for use as energy, some of which are cleaner than others (see below under Energy Technologies).

Carbon Sink

A carbon sink absorbs more carbon from the atmosphere than it releases. Forests, soils, oceans, and wetlands are major carbon sinks, helping slow climate change by removing carbon dioxide from the atmosphere.

Carbon Source

A carbon source releases carbon dioxide into the atmosphere. Common carbon sources include the burning of fossil fuels, industrial processes, transportation, agriculture, and deforestation. Trees can flip from sink to source, absorbing carbon as they grow, but releasing it after they die and decompose or burn.

Global Warming Potential (GWP)

All GHGs are compared to CO2, which has a global warming potential of 1. The GWP measures how much energy the emissions of one ton of a gas will absorb over a given period of time, relative to the emissions of carbon dioxide. 

Mitigation

On the prevention side, mitigation strategies reduce some negative effects of climate change and lessen their impact. Adaptation helps us deal with irreversible damage.

Adaptation

Adaptation refers to adjustments in response to actual or expected climate changes in order to moderate/reduce harm. 

Comment:

While adaptation is essential, it must not replace mitigation in responding to the climate emergency.

Atmospheric River

An atmospheric river is a long, thin, horizontal “corridor” of water vapour, typically associated with a low-level jet stream, which is ahead of the cold front of a cyclonic storm outside the tropics. They transport heat and moisture from the tropics north.

Heat Wave

A heat wave is a prolonged period of abnormally warm weather, typically lasting for days or sometimes even weeks.

Heat Dome

A heat dome is a weather phenomenon where hot air is trapped over a certain area, causing extreme heat.

Tipping Points

Environmental systems can undergo profound upheavals due to global warming, pollution, and the over-exploitation of natural resources. They can push the system beyond a critical threshold—called a ‘tipping point’—into a completely new state, often leading to irreversible changes in the system.

Comment: The earth has reached its first catastrophic tipping point linked to GHGs, with warm water coral reefs now facing a long-term decline.

* Federal Governmental Policies and Programs *

Carbon Tax

This tax is also known as carbon pricing on greenhouse gas emissions from fossil fuel sources: coal, oil, “natural” gas or gasoline.  The aim is to increase the cost of burning polluting fossil fuels to encourage cleaner alternatives.

The Carbon Tax Rebate

The Climate Action Incentive Payment (CAIP), aka the carbon tax rebate, a quarterly payment to eligible Canadians to help with costs related to the carbon tax ended on March 15, 2025.

Carbon Offsets

Companies sell “credits” that people or other companies can buy to “offset” or cancel emissions they generate.

Comment: Offsets do not reduce global emissions: they only “cancel out” emissions that have already happened.

Emissions Cap

This is a designated limit on greenhouse gas emissions, crucial for climate change mitigation.

Comment: Regulations under the Canadian Environmental Protection Act intend to cap emissions by 2030 at levels 20% – 23% below 2019 levels (with the use of offsets) and 35% – 38% (without the use of offsets).

Taxonomy

A taxonomy refers to guidelines which are intended to define what counts as “green” and what does not.  It allows sustainable projects to receive better financial terms as investors earmark capital for clean projects.

Clean Electricity Regulations

Not finalized, and not to take effect before 2035, these regulations are intended to impose a stringent limit on GHG emissions from carbon emitting sources of electric power.

Comment: The regulations contain a loophole for plants commissioned prior to 2025.  These plants can operate for a period of 20 years.

Carbon Capture and Storage (CCS)

Carbon Capture and Storage facilities capture the GHG emissions arising during production and store them in underground reservoirs.

Comment: CCS technology is unproven, inefficient, extremely expensive, and installed at nowhere near the scale required to meet Canada’s emissions reductions goals.

There is also increased risk when the pressure created by injection alone can lead to fractures making the sealing layer leaky.

This technology is heavily promoted and subsidized by the federal government.

Read the SCAN! briefing on this technology. 

Direct Air Capture

There are several possible ways to remove carbon dioxide from the air. They can be classified as nature-based or technology-based.

Comment: Read more in this briefing note.

Greener Homes Program

The Canada Greener Homes Initiative is intended to “help homeowners save money, create new jobs across Canada for energy advisors and fight climate change.”  The program would help low-to-middle-income homeowners and tenants retrofit their homes to reduce monthly energy bills.

* Energy Technologies *

Coal-fired Plants

A coal-fired power station or coal power plant is a thermal power station that burns coal to generate electricity.

Comment: Air pollution particles from coal-fired power plants are more harmful to human health than many experts realized. They are more than twice as likely to contribute to premature deaths as air pollution particles from other sources.

Gas-fired Plants

A gas-fired power plant is a type of fossil fuel power station where chemical energy, stored in fossil gas, mainly methane, is converted into thermal energy, mechanical energy and, finally, electrical energy.

Comment: Gas plants are often the top emitters of nitrogen oxides in communities.

Nuclear Plants

Nuclear energy originates from the splitting of uranium atoms – fission. This generates heat to produce steam, which is used by a turbine generator to generate electricity.

Comment: This technology is very expensive.

Refurbishing aging CANDU reactors and investing in unproven nuclear technology will waste money that could otherwise be invested in renewable energy solutions.  Globally, the cost of renewable electricity is now significantly below not only nuclear power, but also gas.

There is the ongoing, unsolved problem of disposing of nuclear waste.

The federal government is strongly promoting nuclear energy as a “clean” alternative to fossil fuels.

Small Nuclear Reactors (SMRs)

SMRs are nuclear reactors that are “small” (defined as 300 megawatts of electrical power or less), can be largely assembled in a centralized facility, and would be installed in a modular fashion at power generation sites.

Comment: Some climate activists see SMRs as an alternative to fossil fuels.  However, they are costly, unproven, and potentially risky and create dangerous radioactive waste.

Hydrogen

We cannot use the term hydrogen powered energy without breaking it down into sources that have very different effects on emissions.

When it is consumed in a fuel cell, hydrogen produces no carbon emissions — just energy and water. Naturally occurring pure hydrogen is rare.  It has to be produced from other sources.

Grey hydrogen is chemically extracted from fossil fuels, typically methane from natural gas. In the process, CO2 is left behind, so the process generates greenhouse gas emissions.

Blue hydrogen is made the same way as grey hydrogen, except that the CO2 is captured.

Green hydrogen is made by splitting water into hydrogen and oxygen using electricity: electrolysis. To be called “green” the electricity needs to come from renewable energy, such as wind or solar.

Pink hydrogen is similar to green hydrogen, except the electricity comes from nuclear power rather than renewable energy.

White hydrogen is found naturally in underground deposits, which have only recently been discovered.

* Alternative Energy Sources and Technologies *

Renewable energy comes from natural sources.  The energy is replaced at a higher rate than it is consumed.  Examples are sunlight and wind.

Fossil fuels are non-renewable resources that take hundreds of millions of years to form.

Renewable energy sources are increasing in capacity and decreasing in cost.

Wind

Wind energy harnesses the power of moving air by using large wind turbines  installed on land or in marine and freshwater environments. Onshore and offshore wind energy technologies have evolved over the last few years to maximize the electricity they can generate.

The world’s technical potential for wind energy is greater than global electricity production.  There is potential for wind power in most regions of the world.

Solar

Solar energy is the most abundant of all energy resources and can be harnessed in cloudy weather.

Solar technologies convert sunlight into electrical energy, either through photovoltaic panels or through mirrors that concentrate solar radiation.

The cost of manufacturing solar panels makes them often the cheapest form of electricity.

Geothermal

Geothermal energy utilizes the accessible thermal energy from the Earth’s interior. The technology extracts heat from geothermal reservoirs using wells or other means.

Once at the surface, fluids of various temperatures can be used to generate electricity. The technology for electricity generation from hydrothermal reservoirs is mature and reliable.  It has been operating for more than 100 years.

Hydropower

Hydropower harnesses the energy of water moving from higher to lower elevations. It can be generated from reservoirs and rivers. Reservoir hydropower plants rely on stored water in a reservoir, while run-of-river hydropower plants harness energy from the flow of a river.

Hydropower currently is the largest source of renewable energy in the electricity sector.

However, the infrastructure needed to create hydropower can also have an impact on ecosystems in adverse ways.  Many consider small-scale hydro a more environmentally friendly option, and especially suitable for communities in remote locations.

Heat Pumps

They work like a “fridge in reverse”.  They use a mixture of evaporation and condensation to transfer heat from outside to inside a building.

Battery Energy Storage System (BESS)

This system stores electricity for later use.  BESS may charge from the grid or other forms of local generation including wind, solar, generators, etc.

Comment: Applications of BESS may include supporting off grid systems but also commonly are connected to the grid to provide increased stability and diverse grid support services.

* Additional Terms in Use *

Greenwashing

Big Tobacco spent millions to hide the dangers of cigarettes. Big Oil uses the same tactics, spending millions to discourage people from phasing out fossil fuels.

Pathways Alliance not only pollutes heavily but also runs misleading ads to influence government regulations and sway public opinion in favor of oil sands development.  Their ads argue that renewable energy will not provide people with their energy needs.

Decarbonization

This term means removal or reduction of carbon dioxide output into the atmosphere. Decarbonization involves switching to using low carbon energy sources.

Anthropocene

The Anthropocene Epoch is an unofficial unit of geologic time, used to describe the most recent period in Earth’s history. This is the period when human activity started to have a significant impact on the planet’s climate and ecosystems.

The Great Acceleration

The Great Acceleration explains the Anthropocene transition.  The description weaves together human, social, political and economic changes.  These changes created diverse environmental consequences.

Planetary Boundaries

Scientists note nine planetary boundaries beyond which we cannot push Earth systems without putting our societies at risk:

• climate change
• biodiversity loss
• ocean acidification
• ozone depletion
• atmospheric aerosol pollution
• freshwater use
• biogeochemical flows of nitrogen and phosphorus
• system change, and release of novel chemicals

Comment: As of 2025, seven of nine planetary boundaries have been exceeded.

De-Growth

Degrowth means the abolition of economic growth as a social objective. The de-growth objective is to have societies use fewer natural resources to organize and live differently from today.

Ecological economists define degrowth this way: an equitable downscaling of production and consumption in order to reduce societies’ use of energy and raw materials.  This implies reduced consumption.