Climate change

Question 1

Physical causes

Answer 1

1. Milankovitch’s theory: changes in the earth’s orbit/tilt alter the amount of energy reaching the Earth.
2. Every 41,000 years, there is a change in the tilt of the Earth’s axis. A greater tilt means more sunlight in polar regions and over a 97,000-year cycle, the Earth’s orbit stretches.
3. Global temperatures can be raised by peaks of sunspot activity, which follow an 11-year pattern.
4. After volcanic eruptions, large amounts of dust and droplets of sulphur may reflect the sun’s rays lowering temperature.
5. Retreating ice caps release additional fresh water leading to changes in oceanic circulation.
6. This also reduces the albedo effect as reflection has decreased as more land is exposed.
7. Methane is released from melting permafrost

Question 2

Human causes

Answer 2

1. Burning fossil fuels, e.g. coal, oil and natural gas release Carbon Dioxide into the atmosphere.
2. Coal has been used increasingly to power factories/generate electricity in power stations to heat homes.
3. Increased car ownership has resulted in more petrol and diesel being used to fuel cars.
4. Increased car exhaust emissions have resulted in more Nitrous Oxide.
5. Deforestation has resulted in less carbon dioxide being absorbed and the burning rapidly releases more C02.
6. Methane has been released from landfill sites as waste decomposes and when drilling for natural gas.
7. In padi fields, methane is produced by microbes underwater as rice plants decay, Rice production is increasing to meet the demand in rapidly growing countries.
8. The increasing demand for beef has resulted in more methane being created by belching cattle and from animal dung.
9. Methane is more than 20 times as effective in trapping heat than CO2; it accounts for 20% of the enhanced greenhouse effect; and it remains in the atmosphere for 11-12 years.
10. The increased production of fertilisers also adds to the amount of Nitrous Oxide in the atmosphere.
11. Nitrous oxide is 200-300 times more effective in trapping heat than Carbon Dioxide.
12. Refrigerators which are not disposed of correctly release CFCs when the foam insulation inside them is shredded.

Question 3

Impacts

Answer 3

1. Sea level rises caused by thermal expansion of the oceans and also by the melting of glaciers and land-based ice caps.
2. Low-lying coastal areas will suffer flooding, e.g., Bangladesh, leading to large-scale displacement of people and loss of land for farming and destruction of property.
3. Climate change refugees moving to higher ground or to other countries from areas such as Tuvalu or the Maldives will exert more pressure on resources such as housing, water and power supplies in the receiving area.
4. There will be more extreme and more variable weather such as flooding and droughts, and more frequent and intense hurricanes due to increased sea temperatures.
5. An increase in precipitation, particularly in the winter in northern countries.
6. An increase in extent of tropical/vector borne diseases, as warmer areas expand.
7. Up to 40 million more people in Africa being exposed to risk of contracting malaria.
8. Extinction of some land species, due to habitat loss.
9. An increase in sea temperature leads to coral reefs bleaching. Coral expels the algae causing it to turn white.
10. Changes to ocean current circulation may mean the thermohaline circulation starts to lose impact on north–western Europe, resulting in considerably colder winters.
11. A more frequent El Niño/La Niña leads to changes in the monsoon.
12. A prolonged dry season can lead to forest fires, e.g. Australian Bush fires.

Question 4

Solutions

Answer 4

1. Individuals can reduce, reuse and recycle products so that less refuse is sent to landfill sites. This will reduce the amount of methane entering the atmosphere.
2. To reduce the amount of carbon dioxide generated by the burning of fossil fuels, households could reduce energy consumption by insulating their homes or switching lights off.
3. People could also be encouraged to use public transport, walk or cycle, or use hybrid or electric cars to cut down on fossil fuel consumption.
4. Disposal of older fridges should be managed carefully to ensure CFC gases don’t escape.
5. Government Policies such as ‘Helping Households to cut their Energy Bills’ encourages the use of smart meters improving energy efficiency.
6. Increasing the use of low carbon technologies such as windfarms - the UK Government is committed to creating 15% of energy by renewable source.
7. The Paris Agreement outlined agreements between leaders of developed and developing countries to limit climate change to below a 20C rise.
8. The EU has committed to reducing carbon emissions by 20% by 2020.
9. Preparing for extreme weather events such as flooding defences could be built to hold back flood water, eg. The Thames Flood Barrier.

Question 5

Effectiveness of solutions.

Answer 5

1. England’s recycling rates have increased to 45%. UK recycling rates have increased the fastest in Europe over the past decade.
2. In Scotland and the UK there has been increased investment in public transport. However, there is not the necessary infrastructure in place for electric vehicles.
3. New cooling units no longer emit CFCs.
4. Smart meters improve energy efficiency by showing energy costs in pounds and pence. Many homes however still don’t have smart meters as energy companies cannot meet the targets.
5. The US refused to commit to the Kyoto and Paris agreements and major developing countries like China and India are not required to make any reductions.
6. The Thames Flood Barrier has
   successfully protected London from flooding on numerous occasions.
   However, a second barrier may be needed to cope with flooding beyond 2070. Advance warning systems need to be further developed to advise
   householders of the potential risks of flooding.