Fuels and the global environment

Overview

Click on the links above for teaching schemes, activities and web links and other resources related to this topic.

Timing
This topic provides many opportunities for independent research and for the application of Ideas about Science so it could well be extended beyond the minimum of eight or nine hours needed to cover the main points.

Introduction
This topic has close links with the earlier SPU 2 topics of Using Fuels and Electricity Supplies and is relevant to the transport issues raised in Air Quality. It provides opportunities to use almost all the Ideas about Science. The strengths and limitations of modelling are important themes too. Because there are many resources available on the internet some teachers will want to cover a substantial part of the topic through independent research.

A suggested route through the topic

1 Setting the scene

• There is almost certain to be a topical story at the time of teaching. Articles on political arguments about international agreements, a hurricane, a flood, a drought or a dire warning on future climate could all serve equally well as attention attracting introductions to start a discussion. Separation of fact and conjecture and the manipulation of public opinion would be key issues to talk about.
• Natural variation in temperature in the past makes another good starting point for discussion. You can show evidence that seems to indicate that the Earth is warmer than ever or that this is just another fluctuation, depending on the time scale chosen.

2 Greenhouse science
It is worth spending some time consolidating the basic model. With some groups you may also wish to do more quantitative work using the activities from the cpdn web site.

• Everyone has heard of the greenhouse effect but there are also some misconceptions around. A quick question and answer session to find out what students already know with a building up of the model on the board as they provide information would be one start.
• To reinforce the basic idea you could then get students to draw a labelled diagram from memory and then to criticise each other's diagrams. Or you could provide incomplete diagrams to be completed and labelled.
• A diagram showing more details of the energy fluxes involved is built up gradually on the cpdn site.
• Computer modelling of climate is introduced on the cpdn site using a simple excel model to simulate the effect of changes in incoming and outgoing energy on the Earth's temperature.
• A comparison between the temperature of the Earth and those of other planets with different concentrations of greenhouse gases would reinforce the idea that the greenhouse effect is essential for life.

3 Carbon dioxide and the carbon cycle

• You could demonstrate an experiment that shows that carbon dioxide absorbs more IR than air does.
• It is worth revising the carbon cycle. There is a diagram in the textbook on page 157.
• This is also a good place to introduce feedback mechanisms. You can test understanding of the processes involved in the cycle and of positive and negative feedback. With a diagram of the cycle in front of them ask "what if" questions. What would happen to the concentration of carbon dioxide in the air if tree cover, average temperature or fossil fuel use changed?
• Introduce the Mauna Loa data and discuss annual fluctuations and fluctuations in the rate of change. Why is Mauna Loa taken as the standard?

4 Climate change
With a good understanding of the basic science students can now consider the controversies around climate change. There are several activities available. The nature of the controversy is shifting. There is now less argument about whether climate change is happening and more about whether carbon dioxide is the main cause and about what we can do about it.

• The activity 'Why is Carbon Dioxide so Important' allows students to consider the different types of evidence available for the role of carbon dioxide in climate change. Click here for the teachers notes for this activity.
• It would be worth looking at one of the topical controversies about data. Are glaciers receding? What is happening in Antarctica? What is the significance of upper atmosphere temperature measurements? Are soils gaining or losing carbon dioxide? Some analyses depend on estimates of past temperatures. How reliable are these?
• Students could cover most of the main issues in this internet based activity (20 KB) with questions to direct them .
• Another internet based activity is 'Controversial Science' where the teacher presents the climate sceptic case and invites students to do research to challenge this position. Click here for teacher notes and student sheets (81 KB) and a Powerpoint presentation (430 KB).
• Student research could focus on a recent disaster attributed to climate change, such as New Orleans, and investigate the different claims made by different interest groups. This would include the need to consider Social Influences on Science and Technology.

5 Modelling the future

• One possible introduction to this would be to present a range of information from the media and invite students to classify it as measured data or as predictions based on modelling.
• The excel balance sheet on cpdn could be introduced here to show how modelling works.
• Climateprediction.net is a research project that uses idle time on PCs to run a climate model. There is a version for schools which could be run and followed throughout this topic. The results of model runs to date are also available with explanations.
• A simple introduction to the climate system using this diagram could lead to a discussion of how to model the many components shown even in this simple model.
• The same diagram could be used to consider feedback mechanisms in a question and answer session.
• Show one of the predictions from a climate model which gives several different temperatures based on different scenarios. Discuss why there is so much uncertainty. What are the main simplifications and sources of uncertainty in current climate models? See the textbook page 161 and the more detailed Met Office publication.

6 Decision making
This section provides a review of many of the issues covered in the earlier topics. It allows students to develop and practice argument skills and to consider their own responsibilities and choices.

• Collect a list of possible impacts of global climate change in a brain-storming session. Why do we say global climate change rather than global warming?
• The influence of social and economic factors on future carbon dioxide levels has been modelled using a set of scenarios. Discussion of these results would emphasise the importance of decision making.
• Students could each research a different way in which individuals can reduce their carbon dioxide emissions, and present their findings on the benefits and the costs of the measure. The class could then vote on the measure they would be most willing to support.
• Students can practice their argument skills on the issue in this paired debate. (78 KB)
• The use of biofuels has been suggested as one remedial measure. Students can analyse the structure of an argument opposing this approach in a newspaper column in this activity. Click here for the teachers guide (23 KB) and here for the student sheets (25 KB)
• There are many possible topics for research and debate. It will be best to choose one that is topical at the time of teaching. Collect media articles in the weeks beforehand and post these on the class notice board.
• Run a role play of a conference on the issue, with different students taking the role of different interest groups. Make sure adequate briefing materials are available. Possibilities are: an international conference with different nations represented, or a UK conference with different stakeholders.
• Who do you trust for information and advice when making decisions? A questionnaire on who the students and their families trust for advice on this issue could be compared with the results of national surveys carried out in the late 1990s.