B14: Human Population and Pollution Flashcards
How do humans reduce the land mass available to other species?
> Building
Quarrying
Dumping Waste
Farming
Argument for intensive farming
> High crop yield > Easily supervised livestock > Cheaper food > All food is regulated and safe. > Provides enough food for the growing population.
Argument against intensive farming
> Poor living conditions for the livestock
Deforestation and destruction of natural habitats.
Excessive use of fertilisers and pesticides cause environmental and health complications (such as higher risk of cancer).
Animals are injected with chemical hormones to increase the yield.
How is the land polluted?
Toxic chemicals from intensive farming such as pesticides and herbicides are transferred into the soil.
Describe the sequence of events that result in eutrophication.
- Waste products from farming and untreated sewage, especially nitrates, are washed into rivers.
- These stimulate the growth of algae and other water plants.
- These plants then begin to die because of the lack of light due to the competition. Others die naturally.
- This causes a big increase in microorganisms feeding on the dead plants.
- Due to microorganism’s respiration, oxygen levels in water decrease.
- This causes aerobic aquatic animals to die, leading the the pond or stream to become ‘dead’.
How is acid rain formed?
> When fossil fuels are burned, they release sulfur dioxide and nitrogen oxides.
These gases dissolve in water and react with the oxygen in the air to form Sulfuric and nitric acid.
This produces acid rain.
The effects of acid rain on trees.
> The acidity of the rain can kill the leaves, buds, flowers and fruit.
If it soaks into the soil, it can kill the roots as well.
The effect of acid rain on bodies of water.
> As the acid rain falls, the water in the lakes, streams etc becomes slightly acidic.
If the concentration becomes too high, the organisms within the lake die, causing the water to become ‘dead’.
Where does acid rain come from?
> Pollution from factories.
> Car exhausts.
catalytic converters
Remove the acidic nitrogen oxides from car exhaust fumes before they are released into the air.
Desulfurisation processes
> Low sulfur fuels such as gas are becoming more frequent.
Devices have been placed in power station chimneys to clean the flue gases before they are released into the atmosphere.
Global Dimming
The decrease in the amounts of solar radiation reaching the surface of the Earth due to particulates in the air absorbing and reflecting it back into space.
Smog
A haze of small particulates that forms over large cities due to the burning of fossil fuels.
‘Slash and Burn’ clearance
When large swathes of rainforest are cut down and burnt wastefully in order to make room for agriculture and farming.
Three reasons for deforestation
- To grow staple crops for the developed world.
- To rear cattle for the beef burger market.
- To grow crops for biofuels.
