4.9 Carbon Cycle

Greenhouse gases part 1

4.14 Enhanced Greenhouse effect

1. The greenhouse effect is brought about by pollution.
2. Molecules such as Carbon dioxide, water vapour, and methane are greenhouse gases.
3. The concentration of these gases reemit the infrared light back to earth instead of allowing it to escape into space. This raises the average global temperature. This is known as Global warming.
4. The consequences of global warming are the melting of ice caps in the polar regions, resulting in the rise of sea levels. This would change the ocean currents. It would also change the direction of the wind.
5. This would result in climate change.
6. Raising the average global temperature would change the distribution of the world's biomes (major vegetation ecosystems). Due to this deserts would expand

4.13 Greenhouse gases

1. Human activities such as the burning of fossil fuels results in the formation of more carbon dioxide, nitrodioxide, and sulphur dioxide.
2. These are all the greenhouse gases.
3. They absorb infrared light and redistirubute it back to earth.

Human activities that contribute to greenhouse gases

1. The burning of coal, engine emissions, and domestic combustion of coal.
2. Farming is also involved as a contributing factor to greenhouse effect. Cows for instance emmit methane gas.
3. Evaporation of water to form water vapour. These form clouds.
4. Refrigeration, solvents and propelents release the CFCs

4.12 the Greenhouse affect

1. Short wavelengthed UV light is passed into the atmosphere.
2. 50% of this light is reflected back into earth.
3. The other 50% is absorbed by the earth's surface. The UV light is converted and transferred as infrared.
4. The infrared is emmitted back outwards-some of this is lost in space in the form of heat.
5. Major examples of the greenhouse gases are water vapour, methane, carbon dioxide.
6. Infrared waves hit these gases. the gases then reemits these waves in all directions, including downwards. This raises the temperature slightly.
7. Enhanced Greenhouse Effect consists of increases amounts of Carbon Dioxide and methane. This causes more radiation of infrared waves causing the temperature to rise. This then leads to climate change.
8. Chloroflurocarbons are well known for the affect on the ozone layer.

This catalizes the breakdown of O (to the power of 3) to O (to the power of 2).
O3 is much better at absorbing UV light therefore by releasing CFCs we are removing the protection of the ozone layer.

4.11 Gas Pollution

1. The Pollution is caused by sulphur dioxide and carbon monoxide.
2. Sulphur dioxide is added to the atnosphere through the combustion of fossil fuels.
3. The combustion of these fossil fuels results in harmful gases released into the atmosphere.
4. Sukphur dioxide is also released through fuel engines in cars.
5. In the atnosphere, Sulphur dioxide combines with water vapour and forms sulphuric acid.
6. The sulphuric acid is then stored in the clouds which condense to form rainfall. This type of rain is called acid rain.
7. Acid rain burns trees and plants due to the direct effect of the sulphuric acid on the surface of the leaves.
8. Sukphuric acid also affects the plants by leaching calcium and magnesium ions in the soil. This results in the plant not being able to grow.
9. The acid rain precipitation forms streams which will join the lakes. This will reduce the pH and release aluminium ions. This will kill the fish as aluminium will thicken the mucus that lines the gills of the fish. This reduces oxygen supply to the fish.
10. Carbon Monoxide is also produced when fossil fuels are burned with insufficient oxygen. Incomplete combustion.
11. Carbon monoxide combines with the haemoglobin in the red blood cells and forms a molecule known as carbaminohaemoglobin.
12. This blocks haemoglobin from carrying oxygen. This decreases the amount of oxygen being supplied to pther parts of the body.