Carbon dioxide (CO2) is the primary greenhouse gas emitted through human activities. While CO2 occurs naturally in the atmosphere and is part of the earth’s carbon cycle – the exchange of carbon between the atmosphere, oceans, soil, plants, and animals – human activities alter the carbon cycle by adding additional CO2 into the atmosphere and at the same time influence the ability of natural carbon sinks, such as forests and oceans, to remove CO2 from it. Despite the fact that CO2 emissions come from a variety of natural sources, man-made emissions have accounted for the majority of the CO2 increase in the atmosphere since the beginning of the industrialisation.