HKDSE Geography/M7/Human Factors in Global Warming

Numerous human factors lead to global warming.

Carbon dioxide
The main greenhouse gas, carbon dioxide is generated in the following situations:


 * Burning of fossil fuels: The burning of coal, oil and natural gas
 * Burning of petroleum-based fuels by transport: The combustion of fuel for transport, such as aeroplanes and land vehicles
 * Forest fires: Forests are important carbon sinks and carbon dioxide is released into the atmosphere by forest fires.
 * Incinerators: Carbon dioxide is produced when burning solid waste in incinerators.

Methane

 * Livestock rearing: Rearing of livestock, particularly cattle ranching, produces methane.
 * Wet rice cultivation
 * Decomposition of solid waste in landfills
 * Fossil fuel and biofuel combustion also causes methane release

Nitrous oxide

 * Use of nitrate fertilisers in arable farming: When nitrate fertilisers are decomposed in soil, nitrous oxide is released.
 * Fossil fuel combustion
 * Combustion of solid waste in incinerators
 * Nylon production

Chlorofluorocarbons (CFCs)

 * Air conditioning and refrigeration
 * Aerosol sprays
 * Cleaning solvents
 * Styrofoam