Climate Change Model Answers PDF

GLOBAL CLIMATE CHANGE a) Explain the physical causes of climate change. (8) Increased sunspot activity increases global temperatures (1), this follows an 11- year pattern (1). After volcanic eruptions, large amounts of dust and droplets of sulphur are ejected into the atmosphere (1) and may reflect...

GLOBAL CLIMATE CHANGE a) Explain the physical causes of climate change. (8) Increased sunspot activity increases global temperatures (1), this follows an 11- year pattern (1). After volcanic eruptions, large amounts of dust and droplets of sulphur are ejected into the atmosphere (1) and may reflect the sunʼs rays lowering temperature (1). Volcanoes can also release huge amounts of CO2, which traps extra heat in the atmosphere (1) For example the eruption at the Siberian Traps which lasted 2 million years and raised temperatures by 10C (1). Retreating ice caps reduces the albedo effect (1) as more dark land is exposed and this will absorb more heat, rather than reflecting it. (1). As permafrost melts the decaying organic matter held within will release methane (1). Methane is 80x more effective at trapping heat (1). This can also This can lead to a negative feedback loop where more melting causes more methane/ warming, and therefore more melting (1). A physical cause of climate change is Milankovitchʼs theory; changes in the earthʼs orbit/tilt (1) alter the amount of energy reaching the Earth (1). Every 41,000 years, there is a change in the tilt of the Earthʼs axis (1). A greater tilt means more sunlight in Polar regions (1). Meteorites can throw huge amounts of dust and ash into the atmosphere, blocking sunlight and cooling temperatures (1). 65 million years ago, an asteroid hit Mexico causing 20% less sunlight for 10 years (1). Widespread forest fires also resulted from the impact, releasing CO2 (1). Forests could not recover, so photosynthesis decreased meaning more CO2 and global warming (1). b) Explain the human causes of climate change. (8) Carbon Dioxide is released into the atmosphere by the burning fossil fuels, for example coal, oil and natural gas, this will trap heat (1). Coal has been used increasingly to power factories, generate electricity in power stations and to heat homes (1). Deforestation means there are less trees to absorb CO2 (1). Methane has been released from landfill sites as waste decomposes (1). The increase in padi fields to feed rapidly growing populations in Asian countries has increased the amount of methane in the atmosphere (1). The increasing demand for beef has resulted in more methane being created by belching cattle and from animal dung (1). Increased car exhaust emissions have resulted in more Nitrous Oxide (1). Due to rising food demand the increased production of fertilisers also adds to the amount of Nitrous Oxide in the atmosphere (1). Refrigerators which are not disposed of correctly release CFCs when the foam insulation inside them is shredded (1). c) Explain the local and global impacts of climate change. (12) Sea level rises caused by the melting of glaciers and ice caps (1) in Greenland. Low-lying coastal areas will suffer flooding, (1) for example, Bangladesh, leading to large-scale displacement of people (1) and loss of farmland and destruction of property (1). Climate change refugees will exert more pressure on resources such as housing and water supplies in the receiving area (1). More extreme and more variable weather such as flooding and droughts will occur (1) and more frequent and intense hurricanes will be caused due to increased sea temperatures (1). Globally, there will be an increase in rainfall, particularly in winter in northern countries (1). There will be an increase in extent of tropical diseases, as warmer areas expand (1). Up to 40 million more people in Africa will be exposed to risk of contracting malaria (1). Predicted extinction of 10% of land species (1), and coral reefs will suffer 80% bleaching (1) from more CO2 in oceans, turning them more acidic (1). The North-West Passage will be opened up to ships due to melting sea ice (1) meaning more efficient trading routes. (1) Max 2 marks for named examples d) Many strategies have been implemented to both reduce greenhouse gas emissions and to manage the effects of climate change. (i) Describe, in detail, local, national and international strategies you have studied, and (ii) Evaluate their effectiveness. (14) Individuals can reduce, reuse and recycle products so that less refuse is sent to landfill sites (1). This will reduce the amount of methane entering the atmosphere (1 EV). However, Scotland still on recycles about 45% of its waste (1 EV). To reduce the amount of CO2 generated by the burning of fossil fuels households could reduce energy consumption by insulating their homes or switching lights off, etc (1). People are also being encouraged to use public transport, walk or cycle (1), or use hybrid or electric cars to cut down on fossil fuel consumption (1). On a national level the 5p plastic bag charge has meant also meant less waste is sent to landfill, and the policy has successfully resulted in 15 billion fewer plastic bags now in circulation (1 EV). The government is trying to cut back on CO2 emissions by relying on more renewable energy, such as wind or solar power (1). However, some people complain that wind turbines are scars on the landscape and cause noise pollution (1 EV), as well as a hazard to birds who frequently fly into them (1 EV). The government are also preparing for extreme weather events, such as flooding, by building defences to hold back flood water (1), e.g. The Thames Flood Barrier. Countries can try to reduce deforestation by carrying out large scale afforestation in order to soak up more CO2 through photosynthesis (1). However, forests take decades to mature so it will take years to reap the benefits (1 EV). Some governments (e.g. Australia) provide a scheme where companies pay according to the quantity of greenhouse gases they generate, thus encouraging them to be more energy efficient (1). However, wealthy companies are likely to purchase carbon credit offsets instead of actually reducing their emissions (1 EV). On an international level the Paris Agreement outlined agreements between leaders of developed and developing countries to limit climate change to below a 2˚C rise (1). However, the USA – one of the worldʼs biggest greenhouse gas emitters – has now withdrawn (1 EV). Max 3 marks for named examples