Global warming refers to a rise in the average global surface temperature over time. The opposite is global cooling, a decline of the average global surface temperature. Global warming doesn’t mean the planet’s temperature rises all at once. Some areas will be hotter, while others may get colder; however, there is an overall warming trend. Global warming is an example of a change in global climate. Atmospheric temperature data that has been collected for the last 120 years indicates the Earth is warming.

Greenhouse gases (GHGs, or "heat-trapping" gases) trap heat radiation in the atmosphere. The four main GHGs are water vapour, carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). These gases absorb heat reflected by the Earth instead of releasing that heat to space. The greenhouse effect makes Earth habitable by keeping temperatures at a suitable level for life as we know it. Human activities, such driving a car, burns fossil fuels and emits GHGs. GHGs in the atmosphere have increased since the industrial revolution (1750).

Climate change is a long-term change in a region's climate. This includes the entire Earth changing from what is considered normal. These changes can include temperature, wind patterns, or precipitation (rain and snow) levels. Climate change takes place naturally over time because of many different factors, like the distance from the Earth to the Sun, the intensity of sunlight, and the amount of particulate matter in the air reflecting sunlight back into space.

Climate refers to long-term, average weather patterns in a geographic area. Climate conditions (“normals”) are calculated for longer time intervals, such as average weather conditions over 30 years. Weather is what you see outside your window today, or the pattern you notice over shorter time spans (for example, a “rainy week”). Scientists predict that extreme weather events will become more frequent and intense because of changes in the climate.