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Revision:Global Warming
From The Student RoomTSR Wiki > Study Help > Subjects and Revision > Revision Notes > Geography > Global Warming Global warming is the result of an enhanced greenhouse effect. Greenhouses gases such as carbon dioxide, methane, nitrous oxides and chlorofluorocarbons (CFCs) trap the long-wave radiation from the Earth causing the atmosphere to heat up. It is argued that an increase in the amount of greenhouse gases has caused the Earth to warm up by 0.7°C since 1900 and studies show that the rate of increasing atmospheric temperature is accelerating.
Physical Factorso Changing output of solar energy Peaks of sunspot activity seem to raise global mean temperatures. Warm temperatures of the 1940s represent a period oh high solar activity. o Volcanic Eruptions After very violent eruptions, enormous quantities of volcanic dust particles are ejected high into the atmosphere. Global winds distribute the particles, therefore reducing temperatures by shielding the Earth from incoming insolation. E.g. Tambora eruption caused ‘the year without a summer’ in New England, 1816. o Milankovitch Cycles Where the Earth’s orbit around the sun, the angle of the Earth’s tilt and the time of year when the Earth is closest to the sun, change in time in well-defined cycles. Human Factorso Deforestation The clearance and burning of the rainforests for wood and farming land adds to the level of atmospheric CO2 by reducing photosynthesis. o Industrialisation In the 1990s there was an increase in smoke stack industries. The smoke resulted in global warming where energy that is reflected cannot get past the think polluted atmosphere. o Cars Cars have release nitrous oxide from their exhausts. This pollution affects the ozone layer which help keep out much of the sun’s unwanted rays but all the pollution is making holes in it and letting more energy through. o CFCs CFCs from aerosols and refrigerators have reacted with the ozone layer causing thinning and holes. o Methane Methane levels have increased through paddy fields, animal dung and belching cows.
Consequenceso Air temperatures will rise between 1°C and 5°C. o Global sea levels will rise, due to melting ice caps and water expansion as temperatures get warmer. Levels could rise 3.6m by 2100 meaning low lying, populated areas will be flooded e.g. The Nile. Fresh water will be contaminated and people will have to move. As many major cities are ports, they will be at great risk. For example, Tokyo, Venice and New Orleans. o Possible increase in precipitations and storms. Intensity and frequency of tornadoes and hurricanes may increase. o Tropical diseases such as malaria will move as warmer areas will expand.
Solutionso Agriculture Reduction in fertiliser use. Lower livestock ratio (animals per hectare) More environmentally-friendly farming e.g. organic. o Transport Improved engines to reduce emissions by 25% Increased tax on petrol Lower road-tax for cars with smaller engines o Industry Stricter emission of all six greenhouse gases Better management of waste-tips and chemical processing o Energy Develop wind, wave and solar power to replace nuclear power | 
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