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There are significant dilemmas for governments when making decisions about energy sources and reducing greenhouse gas (ghg) emissions. Such dilemmas are present in the situations outlined below. Each of these situations is a starting point for more detailed research into aspects of the climate change issue.
What to do
Provide students with one of the two options to research. Discuss a suitable approach to complete the research task.
Methane: a hero or villain?
Natural gas is mainly methane. When burnt it produces much less carbon dioxide per unit of energy than other fossil fuels. When methane is released into the atmosphere, it is a powerful ghg.
Cattle produce around 200 litres of methane each day. The amount of methane produced depends on the quality of the animal's diet and is therefore related to the wealth of the farmer if the cattle are grain fed, or local rain patterns if the cattle are pasture fed. The production of methane by ruminant animals occurs as part of the process of digesting a diet containing mostly grass. Methane is produced in each of the two stomachs and released through the mouth and anus. It is a natural process. Methane is also generated when animal faeces decompose, especially under wet conditions.
Methane is also produced as a by-product in the sewage treatment plants and in landfill tips. Sewage treatment plants are implementing technology that captures methane produced by bacteria that break down sewage and use this waste gas to produce electricity and power the treatment plant equipment. Landfill sites also capture gases
Prompt students to think about methane gas by asking questions such as:
- How does a sewage treatment plant or landfill site become a source of methane?
- How does using waste gas such as methane help society become more sustainable? What are some of the related issues?
- In what ways are dairy and beef cattle, and sheep economically and socially valuable?
- How could farmers reduce the amount of methane generated on their farms?
- Is methane a hero or villain? Write an essay or prepare a report on this topic.
Coal: a hero or villain?
Coal is used widely to generate electricity in most parts of Australia. It is a major source of carbon dioxide emissions. Australian coal produces small quantities of sulfur dioxide and nitrogen oxides when burnt. European brown coal, on the other hand, produces large quantities of sulfur dioxide and nitrogen oxides, which produce acid rain. In Australia, the reserves of coal are far greater than reserves of natural gas or oil. This has been seen as a great advantage in the past.
Prompt students to think about coal as a source of energy by asking questions such as:
- How might the abundance of natural resources such as coal lead to higher ghg emissions?
- How does coal help to meet Australia's energy needs?
- Why might consumers of electricity not make a connection between electricity use and ghg production?
- Is there a need to adjust the use of coal to meet the energy requirements? Why?
- Prepare a report on the benefits and problems associated with the use of coal.