Ecological zone
A defined area of land characterized by certain environmental conditions and plant communities.

Carbon sequestration
The process by which carbon dioxide (CO₂) is transformed into above- and below-ground biomass and is stored as carbon, primarily in plants.

Carbon pool
Any place where carbon can be found, such as plants, soils, the atmosphere, or fossil fuels. Carbon pools can also be called stocks or reservoirs.

Carbon footprint
A measure of how much carbon dioxide (CO2) a person, organization, or product produces – directly or indirectly – in a certain amount of time (usually a year).

Carbon flux
The process or rate by which carbon moves from one pool to another.

Carbon cycle
The circulation of carbon in nature. Plants absorb carbon dioxide from the air; by photosynthesis, they convert it to carbohydrates, giving off oxygen as a byproduct. Animals then eat the plants and return carbon to the air by exhaling and through decay.

Boreal
The northernmost broad band of mixed coniferous and deciduous trees that stretches across northern North America, Europe, and Asia.

Biosphere
The part of the Earth’s crust, water, and atmosphere where organisms can exist.

Atmosphere
Consists mostly of the troposphere and the stratosphere which comprise the whole mass of air surrounding the Earth. The troposphere is the innermost layer of the atmosphere, containing about 95% of the mass of the Earth’s air and extending 11 miles (17 km) above sea level. The stratosphere is the second layer of the atmosphere and extends from about 11 to 30 miles (17 to 48 km) above the Earth’s surface.

Albedo effect
A measure of how much of the sun’s energy is reflected from Earth back into space.