ABSTRACT
The most serious fossil fuel pollutant is carbon dioxide. This is not in itself toxic, but in conjunction with other gases is the primary greenhouse gas (see Map 1). Most carbon dioxide in the atmosphere stems from burning fossil fuels. Worldwide releases from carbon dioxide from fossil fuel combustion currently amount to 22 billion tonnes per year. Other human activities that produce carbon dioxide include tropical forest destruction (see Map 5), cement production and natural gas burn-off flares. Smaller quantities are produced from natural sources, such as volcanoes and animal respiration.
