Fossil fuel combustion releases co2 to the atmosphere. All carbon based fuels that are not renewable because they take so long to form in the earth. Annual global co2 emissions is about 37 billion metric tons. About half of the co2 remains in atmosphere. Most of the remainder goes into ocean. Some is taken up by land plants. When we remove plants and deforest old growth forests, we change the amount of co2 that is taken up by the atmosphere. Rate at which it is being emitted increasing too. Linked to acceleration of fossil fuel combustion. Co2 is mostly coming from electricity generation (burning of coal) Carbon dioxide (fossil fuel and industrial processes) (most) Carbon dioxide (forestry and other land use) Greenhouse gases can last a long time in the atmosphere. What clothes to wear on a particular day. Climate is average conditions in a particular area over a long period of time. What clothes to have in your closet.