Carbon dioxide is naturally present in the atmosphere as part of the Earth's carbon cycle.
The global carbon cycle is a system of processes that transfers carbon in various forms through the Earth’s different parts - the atmosphere, oceans, soil, plants, and animals.
So carbon moves around — it flows — from place to place.
Carbon dioxide (CO2) is the main greenhouse gas emitted through human activities.
Human activities change the carbon cycle.
First, by adding more CO2 to the atmosphere, mainly by burning fossil fuels.
Also by changing the ability of natural sinks, like forests, to remove CO2 from the atmosphere.
Human-related emissions are responsible for the increase that has occurred in the atmosphere since the industrial revolution.