Climate change is the long-term change in weather patterns
(e.g. an increase or decrease in extreme weather events, such as hurricanes, droughts or floods) over periods of time ranging from decades to millions of years. The terms “climate change” and “global warming” are often used interchangeably. However, global warming pertains only to the average increase in the Earth’s surface temperature, while climate change covers a wide range of potential changes in weather patterns, including changes in temperature and precipitation.

Among other impacts, climate changes can negatively affect habitat by creating changes in average temperatures and precipitation that may make it difficult for plants, animals and humans to survive. Greenhouse gases produced by humans, mainly through the burning of fossil fuels (e.g. coal, oil and petroleum products like gasoline), are a significant contributor to modern climate change.

Climate is the average weather over a long period of time.

Weather is the current or short-term state of the atmosphere. Weather includes temperature, precipitation, humidity and wind, among other conditions.

Greenhouse gases (GHGs) are gases that absorb and trap heat in the atmosphere. Carbon dioxide (CO₂) is the main naturally-occurring GHG. The most common human-produced GHGs are CO₂, methane (CH₄) and nitrous oxide (N₂O). GHG emissions result from the burning of fossil fuels for residential and industrial purposes (producing mainly CO₂), from agricultural and oilfield activities (mainly CH₄), and from vehicle emissions (mainly CO₂ and N₂O).

GHGs are also emitted from natural sources such as volcanoes and forest fires. Water vapour is another important GHG. All GHGs released to the atmosphere contribute to the greenhouse effect, regardless of where in the world they are emitted.

The greenhouse effect is a naturally occurring phenomenon in which GHGs in the atmosphere absorb and trap heat energy that is radiated back from the Earth’s surface – like wrapping a blanket around the Earth to keep it warm and habitable. However, human activities are adding more GHGs to the atmosphere, interfering with the natural carbon balance, increasing the greenhouse effect and raising the Earth’s temperature. These increased temperatures can lead to more frequent and extreme weather events, which can be associated with climate change.

Being carbon neutral means balancing the amount of CO₂ emitted to the atmosphere with actions to reduce or offset these emissions in other places, so the net effect is zero carbon emissions. For example, a community might plant trees to absorb GHG emissions that are produced as we heat and power local buildings. Thus, although GHGs are emitted, actions are being taken to reduce the net emissions, moving us closer to being carbon neutral. When talking about carbon neutrality, the terms carbon, carbon dioxide and greenhouse gas emissions are often used interchangeably.