B6.1 - Global Challenges Flashcards
What is deforestation?
The practice of cutting down trees
Causes of deforestation?
- Industrial use
- Agriculture
- Lifestyle (eg making space for homes)
Environmental impacts of deforesation?
- Less trees absorbing CO2 from environment
- Trees release carbon stores as C02 when cut down
- Many habitats destroyed
What are Peats?
Peats are partially decomposed plants and moss
Where are peats formed?
They are formed in waterlogged bogs and acidic fens over thousands of years.
How are Peats formed?
It is formed as the moss and plants don’t completely decompose in the waters with lack of oxygen (anaerobic waters) fully.
How are peats useful?
1) As fuel: Peats can be decomposed as fuel due to stored CO2.
2) For Agriculture: Mixing peat with soil increases water retention, mineral retention and soil structure
Issues with using peats?
1) Releases CO2 (Global warming)
2) Habitats destroyed - bogs are drained in order obtain peat.
What is waste?
Something unwanted that we need to rid of.
What is bioaccumulation?
The build up of toxic chemicals at the top of the food chain. The higher up the food chain, the higher concentration of toxic chemicals.
How is acid rain formed?
When gases from combustion of fossil fuels react with water producing acid.
3 gases that cause acid rain:
- Sulphur dioxide
- Nitrogen oxide
- Carbon dioxide
3 equations for acid rain:
Sulphur dioxide + water -> Sulphuric acid
Nitrogen oxide + water -> Nitric acid
Carbon dioxide +water -> Carbonic acid
How are the 3 gases in acid rain formed?
Sulphur dioxide = Burning oil and coal
Nitrogen oxide = Burning petrol in cars
Carbon dioxide = Burning fossil fuels and deforestation
Effects of acid rain?
- Causes mineral deficiency in soil
- washed aluminium ions into water affecting fish gills
- damages roots and leaves of plants
- acidifies water so aquatic organisms can’t survive
What is Eutrophication?
A process which occurs when fertilisers are washed into waters.
Steps to Eutrophication:
1) Farmers add an addition of nitrates (fertilisers) into soil in order to increase the growth of crops.
2) The fertilisers are washed into bodies of waters and cause an increased growth of aquatic plants (like pondweeds).
3) These aquatic plants grow at the surface of waters preventing sunlight to pass through to plants submerged in water. These plants die due to lack of Photosynthesis.
4) Microorganisms decompose the dead plant material and respire while doing so.
5) The microorganisms respiring cause oxygen deficiency in waters.
6) Aquatic animals die as they suffocate due to lack of oxygen.
How does a fuel burning power station work?
COAL -> FURNACE -> THERMAL ENERGY -> HEATS WATER TO BOILING WHERE IS TURNS TO A GAS (KINETIC ENERGY) -> TURNS GENERATOR -> ELECTRICAL ENERGY.
What is Carbon dioxide in the combustion of fossil fuel?
It is a by product
FUEL + OXYGEN -> WATER + CARBON DIOXIDE
What is the enhanced greenhouse effect?
1) The sun emits rays to Earth and some reflect
2) Sun rays try to travel back out to space once deflected off Earth
3) The greenhouse gases absorb suns rays and emit them back to Earth
4) This trapment of rays increases Earths temperature
What is an indicator species?
A species which can be used to measure environmental change.
What are Lichens?
They are an indicator species measuring air quality:
They are sensitive to sulphur dioxide
High pollution : low lichen population
Low pollution: High pollution population