Climate Change

Question 1

Physical Causes

Answer 1

• Volcanoes - CO2 aids greenhouse effect, sulphur dioxide combines with water and oxygen to form sulphuric acid before condensing into sulphuric aerosol droplets which causes cooling by the haze intercepting solar radiation, dust and ash if it reaches the stratosphere it can be blown around the earth and blocks the suns energy from the reaching the earth.
• Sun Spot Activity - The sun has periods where it can emits additional energy and times when it is less active. Periods of high sunspot activity result in increased brightness and more energy being received by the earth. Sunspot activity tends to happen in 11 year cycles.
• Eccentricity - Sometimes the earth’s orbit becomes more elliptical in shape. This means that the amount of energy received will vary leading to warmer and cooler periods. This happens on a 97,000 year cycles. When the orbit is more oval it spends longer periods further away from the sun.
• Axial Obliquity - If changes in the angle of the earths axis mean that the poles are tilted more towards the sun so recieve more solar energy. This happens roughly every 41,000 years.
• Melting Permafrost - During the summer months in the arctic, the top layer defrosts and becomes marshy (muskeg) as it has nowhere to drain with the permafrost underneath. Vegetation can therefore decay in the water and marsh areas and as it rots it releases methane gas as organic matter decomposes.
• Fumeroles - These are vents in the earths surface which releases CO2, hydrogen sulphate and hydrogen chloride. These gases can absorb solar radiation which can then warm the planet.
• Melting Ice - Melting ice releases more fresh water into oceans. This can lead to changes in ocean circulation. It can also reduce the abedo effect so earth absorbs rather than reflects energy.

Question 2

Human Causes

Answer 2

Carbon Dioxide
* Burning fossil fuels releases CO2 into the atmosphere, which will trap heat. Coal has been used increasingly to power industry and generate electricity as well as heating homes.
* Increased population means there is more need for electricity as more people have appliances, electronic devices etc in their homes which increase demand for electricity.
* Deforestation especially in the Amazon Rainforest has resulted in less carbon dioxide being absorbed by the trees. In addition, trees are often burned to clear them which releases more CO2.
Methane
* Methane has been released from landfill sites as waste decomposes - as population increases more waste is created so more methane is released.
* Increasing global population also means increasing demand for beef has resulted in more methane being released from belching cattle.
Nitrous Oxides
* More cars on road/increasing population has also increased car exhaust emissions - these are a common sourse of nitrous oxides.
* Power stations also produce nitrohs oxides so the increase in electricity due to a rising populations relying on charging devices etc increases release of nitrous oxides.
* Due to rising food demand the increased population of fertilisers also adds to the amount of nitrous oxides in the atmosphere.
CFCs
* Fridges not disposed of correctly release CFCs when the foam insulation inside them is shredded.
* As global temperatures rise there is a need for aircon. The coolants used in air conditioning systems create CFCs which must be disposed of correctly.

Question 3

Local impacts

Answer 3

• Increased average rainfall
• Flooding will damage houses and can destroy transport links which can isolate villages. Cuts off access to school, businesses will be destroyed, insurance costs rise in areas, pressure on emergency services.
• More money is spent on flood defences, crops are unable to grown leading to increased food prices.
• Historic buildings become more weathered and dangerous, flooded sewage systems can lead to disease.
• Increased Annual Temperatures
• Increase cases of heatstroke increasing deaths in young, old and those with medical conditions which puts pressure on the health services.
• Less snow means less people go skiing leading to a loss of jobs therefore impacting the local economy. Longer growing season increases yield and profit. Tourists are attracted to warmer destinations so there will be an increase in sales of ice cream boosting the local economy.
• Mosquitos can migrate further north leading to a spread of malaria and strained healthcare. Increased use of insecticides damaging to environment.
• Rising sea level
• Coastal erosion may lead to destruction of houses/businesses leading to people being displaced. Coastal flooding brings flooding of homes and businesses.
• Reduced population/amenities and natural beauty result in less tourism. Coastal sea defences need to be built, which costs money. Local council and governments may not be able to afford these leading to cuts elsewhere.
• Increase in coastal erosion - loss of habitat and important sites for conservation and scientific interest. Destruction of salt marshes leads to loss of habitats for animals and plants.

Question 4

Global impacts

Answer 4

• Sea Levels Rise
• Low-lying coastal areas such as Bangladesh and the Ganges Basin will experience a large-scale displacement of people, loss of agricultural land and food supply and destruction of property. Over 125 million people would be displaced and over 300 million people who rely on its foodstuffs and fish would be affected. Salt water would intrude into wells contaminating drinking water supplies.
• Some islands eg Maldives or Tuvalu will become completely uninhabitable. This will lead to loss of homes, farm land and tourist income.
• Extreme Weather
• We are likely to see an increase in the intensity and frequency of storms. In areas such as the USA this could lead to increased number of hurricanes in coastal areas to the South and flooding.
• This could damage and destroy housing and infrastructure which will also affect business and people’s livelihoods and may have an impact on the tourist industry eg in Florida. It may cause a mass migration of people out of affected areas.
• Increased rainfall could lead to saturated soil and landslides. Many poorly built buildings eg the Favelas in Rio de Janeiro may be destroyed.
• Increased rain and warmer weather in the USA and Canada may see a 20% increase in crop yields due to longer grower season.
• Drought
• In areas such as the Sahel, land drying out would lead to a decrease in crop yields. This could lead to starvation and famine resulting in the amss migration of people out of the area.
• Decline of water supplies could lead to conflict. People would struggle to find water for irrigation systems or for their livestock which will also lead to the same situation as above.
• Increased risk of forest fires eg Australia and California. Leads to loss of species and damage to property.
• Disease
• Increased temperatures could lead to a migration of female anopheles mosquitos which spread malaria. More rainfall and flooding creates more areas of standing water which provides breeding grounds which weren’t available before.
• Flooding will lead to increased spread of water borne diseases such as river blindness.
• Overflowing of open sewage systems may lead to increases of cholera or diarrhoea.
• Leads to ill health and pressure on health service.

Question 5

Management strategies and effectiveness

Answer 5

• Promoting Energy Efficient Products
• Energy efficient light bulbs use less energy so less fossil fuels are burned in generating electricity. They last 10-50 times longer than traditional bulbs so there is less wastage.
• Government grants for cavity wall insulation to make homes better isulated. This means that 20% less energy is used to heat them.
• Smart meters which allow users to monitor the amount of electricity they are using.
• Effectiveness
• On such a small scale, the impact on GHG emissions is small. Many people don’t like these light bulbs as they are dimmer so won’t use them. Not every home is able to get cavity wall insulation.
• Reduce, Reuse, Recycle
• RRR is aimed at saving energy in the manufacturing and disposing of products. Food waste composting reduces the amount of rotting food in landfill and therefore cuts down on methane emissions. The Scottish government has set a target of 70% of recycling by 2025.
• 10p charge for carrier bags (5p since 2014 increased in 2021) to reduce energy and material wasted producing bags.
• Effectiveness
• Some aspects have worked very well eg 10p carrier bags has massively reduced waste in the production of carrier bags.
• The Scottish government has increased recycling rates from <5% when the Parliament began in 1999 to over 45% in 2018. This varies from council to council however with West Lothian recycling around 65% of waste but the Scottish Borders currently at 39%.
• Encouraging people to eat less meat
• 51% of GHG emissions are from animal agriculture. If we eat less meat, fewer livestock will be needed and so less methane will be produced. More land will be available for crops and more trees could be planted.
• Promotion of vegan lifestyle eg veganuary.
• Effectiveness
• Increasing global population means that there is a greater demand for meat.
• Changing attitudes is difficult in countries like UK with ‘meat and 2 veg’ culture.
• Many meat free alternatives have large carbon footprint due to coming from abroad.
• Soya grown in rainforest plantations which increases deforestation.
• Public Transport & Cars
• Electric car/hybrid cars/stop start are more efficient with lower CO2 emissions so they not only use less fuel but produce less pollution. Stop start technology automatically switches the engine off when the car is stationary.
• Such cars also have much cheaper road tax so there is additional finance incentive.
• Public transport options
• Diesel car ban by UK Government by 2030.
• Effectiveness
• Many green cars are very expensive so people cannot afford to buy them.
• Hybrids or electric cars are not great for longer journeys as they need to be recharged which can be inconvenient.
• Diesel cars are energy efficient but also release particulates which contributes to air pollution in cities.
• Limits to public transport.
• Renewable energy
• Solar panels are used by both individual householders as well as large scale social energy ‘farms’.