Enhanced greenhouse effect – a hot international topic

Key text

The natural greenhouse effect

The natural greenhouse effect is a phenomenon created by the heat energy radiated by the sun and greenhouse gases normally present in the atmosphere. In simple terms, sunlight passes through the atmosphere, warming the Earth. In turn, the Earth radiates this energy back towards space. As it passes through the atmosphere, greenhouse gases (water vapour, carbon dioxide, methane and nitrous oxide) absorb part of the energy, while the remainder escapes into space. This means that some of the sun's energy becomes trapped – thus making the lower part of the atmosphere, and Earth, warmer.

Image: IPCC 2007

Energy in balance

If the atmosphere accumulated all the trapped heat, then the Earth's temperature would just rise and rise, but it doesn't. The temperature only rises until the amount of infrared or long wave radiation leaving the Earth balances the amount of energy coming in from the sun. As long as the amount of greenhouse gases in the air stays the same, and as long as the amount of heat arriving from the sun is constant, an equilibrium is established. This is a steady state where as much energy is lost to space as is gained from the sun. In equilibrium, the natural greenhouse effect maintains the average temperature of Earth at around 14°C.

The atmosphere is changing

The Earth's atmosphere is made up of 78 per cent nitrogen and 21 per cent oxygen. Only about 1 per cent is made up of natural greenhouse gases, but this comparatively small amount of gas makes a big difference. Before the Industrial Revolution (which started in England about 200 years ago) the mix of gases that made up the atmosphere was relatively constant. The Industrial Revolution brought new industrial processes, more extensive agriculture, and a rapid increase in the world's population. This rapid increase in human activity meant that more of the gases which cause the greenhouse effect were released into the atmosphere. We know this because of measurements made over the last 35 years and the analysis of air bubbles trapped in ancient ice. There is now clear evidence that levels of carbon dioxide, methane, nitrous oxide and halocarbons are increasing (Box 1: Greenhouse gases).

The enhanced greenhouse effect and climate change

Many scientists think that the increasing concentrations of these greenhouse gases has led to an increase in the world's average temperature. This is called the enhanced greenhouse effect.

While scientists agree that the levels of greenhouse gases are rising, there is less certainty about what the precise effects of this will be. To help them understand these effects, scientists use mathematical models (Box 2: What is modelling?). These models take account of many processes that together determine the behaviour of the atmosphere (eg, temperature, humidity, wind speed and atmospheric pressure). Many researchers are predicting that the world will get warmer, but exactly how much warmer or how quickly it will happen is still being debated (Box 3: Global warming and climate change).

A national and international issue

An increase in global temperature would bring changes to the entire planet, and therefore to every nation. This makes it an international issue which needs worldwide study and responses (Box 4: International deliberations). But individual countries are each responsible for their own greenhouse gas production. Australia produces about 1.5 per cent of the world's anthropogenic greenhouse gases. We have very high emissions of greenhouse gases relative to other developed countries, considering the size of our population and economy (Box 5: Australia's policy response). One of the reasons for this is that other nations have reduced their carbon dioxide emissions because they use more natural gas and nuclear power instead of oil and coal.

Australia and over 150 other countries signed the United Nations Framework Convention on Climate Change at the first Earth Summit held in Rio de Janeiro in 1992. This agreement set up a process which enabled governments to meet regularly to discuss action to avert extreme climate change. As a result of subsequent talks, all developed countries were asked to reduce their greenhouse gas emissions to 1990 levels. In December 1997, a conference of governments held in Japan attempted to reach legally binding agreements about what each country should do. The idea was for each country to reduce its greenhouse gas output by a similar percentage.

The Australian government argued that this was not fair on Australia because we have a different sort of economy from some other developed nations, and would suffer economic and social costs if we reduced our emissions by the same percentage as other countries. But if we used nuclear power or more natural gas or more renewable energy sources such as solar power then we wouldn't need to create so much carbon dioxide and other greenhouse gases.

There was also some dispute about the accuracy of the mathematical model used to calculate the effect of reducing our greenhouse gases. This is important because the government's argument was partly based on the predictions of this model.

Australian scientists

Australian scientists are working on many aspects of the greenhouse effect. Some scientists try to determine climatic trends. Others model the effect of the enhanced greenhouse effect on Australia's climate and economy. Still others live and work on the Antarctic ice cap, to see what effect the enhanced greenhouse effect may be having there. All this is part of a worldwide attempt to better understand what may be causing global warming and to decide what can be done about it.

Related Nova topics:

Acid test for the seas

Impact of global warming on biodiversity

Predicting natural events

Warmer and sicker? Global warming and human health

Getting into hot water – global warming and rising sea levels

Coral bleaching – will global warming kill the reefs?

Carbon currency – the credits and debits of carbon emissions trading

The Southern Ocean and global climate

Box 1. Greenhouse gases

But how can we find out the CO₂ concentrations that existed before this regular monitoring started? Evidence comes from a variety of sources, but one of the most straightforward involves taking ice samples from the polar ice caps. Ice in Antarctica builds up from the compression of each year's snowfalls. By drilling down into the ice cap (which is up to 4 kilometres thick), scientists can collect core samples of the annual snowfall going back over thousands of years. The deeper you go, the older the ice.

This ice contains air bubbles, captured when the snow fell and sealed in ice since that time. Scientists can take a slice of a core and analyse the air trapped within the bubbles. This ice record can give us information about the air from as far back as 800,000 years ago. The ice record shows that for many thousands of years the CO₂ concentration slowly fluctuated. It remained steady during the last few thousand years, but began to increase about the year 1800 – as did methane and nitrous oxide. Greenhouse gases are now higher than they were at any time over the last 800,000 years.

Human activity causes increases in greenhouse gases

Carbon dioxide

The increase in CO₂ is partly caused by fossil-fuel burning, cement manufacture, land clearing, forest harvesting and changes in agricultural practice. According to the National Greenhouse Gas Inventory of 2005, CO₂ accounts for 74.3 per cent of Australia's greenhouse gas emissions.

Methane

Emissions from landfill, biomass burning, increased agricultural production in rice paddy fields, digestive fermentation (burps and farts) from cattle and other livestock, and leaks from natural gas pipelines and coal mines have lead to a steady increase in methane emissions. Methane production accounts for only 20.2 per cent of Australia's greenhouse gas emissions. However, it is 20 times more potent as a greenhouse gas than CO₂ and levels have increased at a faster rate. Scientists are concerned that global warming will result in the release of even more methane if permafrost melts.

Nitrous oxide

There are many small sources of this gas both natural and manufactured that are difficult to quantify. The main sources created by human activity are from agriculture (especially the development of pastures in tropical regions), biomass burning and number of industrial processes. Nitrous oxide production accounts for only 4.3 per cent of Australia's greenhouse gas emissions but it is 200 to 300 times more potent as a greenhouse gas compared to CO₂.

Halocarbons

Chlorofluorocarbons (CFCs) are halocarbons which were widely used for propellants, refrigerants, and foaming agents. Their use rapidly increased after their invention in the 1930s. The realisation that they were responsible for ozone depletion in the stratosphere has led to their phasing out under the 1987 Montreal Protocol. Perfluorocarbons, another type of halocarbon, are produced during aluminium production. Halocarbon production accounts for 1.1 per cent of Australia's greenhouse gas emissions. (Despite their small concentrations, halocarbons have a significant greenhouse effect.)

Related sites

• National Greenhouse Gas Inventory (Australian Greenhouse Office)

• Climate change: The greenhouse gases (British Broadcasting Corporation, UK)

Box 2. What is modelling?

Mathematics is one of the most important modelling tools. The ancient Egyptians used geometry to model and divide up their farmland. In the 1600s, Isaac Newton developed calculus, a way of mathematically describing moving objects. He used equations to accurately model the motion of the planets – one of the greatest scientific achievements. Today we use sophisticated computer models in many ways; for example, to help predict the weather, simulate climate change, and assess the impact of population on the environment.

How does modelling work?

Modelling is a five-step process. A simple way to see how the steps work is to imagine that you have been asked to organise a function for 30 people. Your problem is to decide how much to charge each person to cover all the costs.

Step 1. Get a clear picture of the problem.
Decide what things have to be bought or hired for the function.

Step 2. Choose the most appropriate mathematics to solve the problem and then present the problem in mathematical language.
In this case you would choose estimation, addition and division.

Step 3. Solve the mathematical problem.
Estimate how much a typical person would eat and drink and work out the costs involved. Add them all up and divide by 30 – the number of people coming to the function.

Step 4. Translate your answer back into the language of the original problem.
The amount, in dollars, you would need to charge each person.

Step 5. Check the solution your mathematics has produced. Is it a good enough answer for your needs?
The amount you charge each person should be affordable and comparable with charges for similar functions.

What makes a good model?

The aim of a model is to simplify the problem. Using a street directory to find your way around a city is much easier than using trial and error or just heading off in one direction. However you usually have to reach a balance between simplicity and accuracy. Seasons give us a simple model for general weather patterns – hot or cold, wet or dry. But the model may not be accurate on any particular day.

Good models must include the most significant factors and describe the most important features of a problem but may omit factors of minor importance. You would expect that temperature measurements might be important for a weather model, and the model should tell you if it will rain or not. But the cost of potato chips is not a factor that should be in a model about weather!

Finally, a good model must be accurate enough to make predictions. Your costing of the function is not very useful if no-one could afford to come. Similarly, if a weather model predicts warm sunshine but it snows instead, then the model should be checked.

Modelling is important for solving problems, we do it all the time. But there are always more problems, and more ways of making models – great challenges still remain.

Related sites

• How reliable are climate models? (Australian Government Department of Climate Change)

• Applied mathematical modelling technologies – some recent projects (CSIRO Mathematical and Information Sciences)

• Types of climate models (Hadley Centre for Climate Prediction and Research, UK)

• Modelling climate (Nova: Science in the news, Australian Academy of Science)

Box 3. Global warming and climate change

Evidence that the climate is changing is shown in the melting of ice-sheets and snow, warming oceans and rising sea levels. Other changes could affect the oceans even more drastically by increasing its acidity and the number of coral bleaching events.

With climate change climatic zones would be expected to shift – meaning that some species (including farmed species) may no longer be able to survive in their current locations. Whether or not natural ecosystems could adapt readily remains to be seen. Perhaps some could, but certain species, tolerant of only a narrow band of temperature and unable to move their range fast enough, could become extinct.

Predicting the future is difficult

While the basic physics of the greenhouse effect is well understood, predicting the future course of events is made difficult because of our insufficient knowledge about the detailed behaviours of the atmosphere and oceans. There are at least five areas of incomplete understanding:

• sources (places of origin) and sinks (places of storage) of greenhouse gases – which affect predictions of future concentrations;

• clouds – which strongly influence the magnitude of climate change;

• oceans – which influence the timing and patterns of climate change;

• polar ice-sheets – which affect the predictions of sea-level rise;

• land surface processes and feedback (when the output of a system affects the input) – which affect hydrological and ecological processes.

There are also limitations to the computer models which are used to simulate an Earth-atmosphere system.

Related sites

• Climate change 2007: The physical science basis (Intergovernmental Panel on Climate Change)

• Global climate change (British Broadcasting Corporation, United Kingdom)

• Predicting climate change (Oak Ridge National Laboratory, USA)

Box 4. International deliberations

In the 1980s the World Meteorological Organization and the United Nations Environment Programme established an international panel of government representatives and scientists to review the science of climate change. Known as the Intergovernmental Panel on Climate Change (IPCC), it has published numerous extensive reports that have become the source for much of the material used in discussions and decision-making about the enhanced greenhouse effect.

At the 1992 Earth Summit in Rio de Janeiro, Australia and about 150 other countries signed the UN Framework Convention on Climate Change. Australia ratified the convention in December 1992. As a party to the convention, Australia must report its greenhouse gas emissions and the strategies and measures it has adopted to reduce them.

The stated objective of the Framework Convention is to achieve

The countries party to the UN Framework Convention on Climate Change met in Berlin in early 1995 in what is known as the first meeting of the Conference of the Parties (COP1). They agreed to continue cooperating internationally on the enhanced greenhouse effect. But there was little agreement on what measures could be implemented. After much negotiation, delegates started work on a protocol.

COP2 was held in July 1996 in Geneva. There, the countries agreed that talks on reducing greenhouse gas emissions should be accelerated.

Earth Summit II in New York in June 1997 reviewed how successfully Earth Summit I commitments had been implemented in the 5 years since they were agreed to. Australia’s opposition to legally binding, uniform targets on greenhouse gas emissions received international criticism. The Australian Government argued that all nations start at a different base with respect to greenhouse gases. For example, some countries have copious supplies of hydroelectricity, others depend on inputs of energy-intensive methods, still others have economies that are less energy dependent. Within the European Union differential targets were allowed for these and other reasons. Thus, in this regard, Australia's approach was not that different.

COP3 took place in Kyoto, Japan in December 1997, resulting in the Kyoto Protocol. This agreement sets the collective global target of reducing greenhouse gas emissions by about 5 per cent of 1990 levels by 2012. Australia, which argued that it was a special case because of increasing population, dependence on fossil fuels and a decentralised economy, had its target set at 8 per cent above 1990 levels.

COP4 took place in Buenos Aires, Argentina in November 1998, where a 2-year plan of action was adopted to reduce the risk of global climate change.

COP5 was held in Bonn, Germany in October/November 1999. Progress was made on the following issues: accelerating the negotiation process; Kyoto mechanisms; land-use, land use change and forestry; and compliance. In November 2000, negotiations were suspended at COP6 when no agreement was reached on rules to make the Kyoto Protocol operational.

COP6 resumed in July 2001 in Bonn, Germany. Although the United States was not part of the talks, other industrialised nations reached partial agreement about how to begin addressing the problem of climate change.

At COP7, held in Marrakesh, Morocco in November 2001, extended discussions produced a rule book for the Kyoto Protocol, clearing the way for ratification.

COP8 was held in Delhi, India in October 2002, where participants urged that the Kyoto Protocol be brought into force as quickly as possible, and agreed on procedural rules related to documentation and reporting of emissions. Discussions on the obligations of developing countries to meet emissions targets were heated.

At COP9, held in Milan, Italy in December 2003, there was a call for Russia to ratify the protocol, discussion about technicalities relating to carbon sinks and the formation of two funds to assist developing countries.

COP10 was held in Buenos Aires, Argentina in December 2004, and focused on preparation for the implementation of the Kyoto Protocol, after Russia agreed to ratify the protocol. There was discussion about bringing existing policies into force and the next phase of negotiations, without any new commitments being made beyond 2012.

The Kyoto Protocol came into force on 16 February 2005 at COP11. Meetings continue to be held annually with the attention of advocates of the protocol now turned to strengthening the agreement for the years following the initial commitment period of 2008 to 2012. One of the challenges is to include all of the major emitting countries, both developed and developing. Another is to begin significant long term reductions in carbon emissions to prevent further climate change.

At COP 12 in Nairobi, strategies were discussed for the international climate effort, deforestation and ways to encourage greater action by developing countries. In 2007, COP13 in Bali, Indonesia, culminated in the adoption of the Bali Road Map. This presented international strategies for tackling global climate change and an agenda for development of the successor to the Kyoto Protocol.

At COP 14 in Poznan, work programs were developed for negotiations in the lead up to forming an international response to climate change at COP 15. Issues such as adaptation, emissions from deforestation and finance – of particular importance to developing countries – were also addressed.

COP 15 was held in Copenhagen in 2009. In an international agreement to form the basis of a post-2012 framework when the Kyoto Protocol expires, the Copenhagen Accord set a cap on global temperature rise to below two degrees. This is to be achieved through commitment of countries to significant emission reductions. Countries also agreed to raise finance to support action in the developing world on climate change.

Related sites

• Meetings archive (United Nations Framework Convention on Climate Change)

Box 5. Australia's policy response

The National Greenhouse Response Strategy was replaced in late 1996 by the National Greenhouse Strategy. It is the primary mechanism through which our international commitments will be met.

Under this strategy, a number of programs have been launched or continued. For example, the Greenhouse Challenge Plus, launched in March 2005, is a cooperative effort between Australian industry and the Commonwealth Government to reduce greenhouse emissions through voluntary industry action. Around 780 Australian companies are part of the program. Another scheme allows carbon 'pooling' so that growers of small forests can group together to participate in abatement programs.

Australia signed the Kyoto Protocol in 1998, but the agreement was not ratified until December 2007.

In 2005, the National Greenhouse Gas Inventory – the annual statistical report on greenhouse gas emissions – stated that Australia had achieved 102.2 per cent increase in emissions and is on course to meet the emissions target of 108 per cent. While this is an increase in emissions, if business had continued 'as usual' the emissions would be 125 per cent of 1990 levels by 2008-2012. The difference between what has been achieved and what would have occurred without change in policy is equivalent to removing every car in Australia from the road.

The response of the New South Wales and Australian Capital Territory governments

About half of Australia's carbon emissions come from coal-fired electricity generating stations. Unlike many countries, we do not have nuclear power stations or large hydro schemes to produce electricity. In Australia, NSW and the ACT are the only states to have mandatory Greenhouse Gas Abatement Schemes. The NSW scheme was introduced in January 2003 and the ACT scheme in January 2005. Both schemes are interlinked and involve cooperation between the states. Electricity retailers must now meet mandatory targets for reducing the emission of greenhouse gases from the production of the electricity they supply or use.

The NSW and ACT targets for emissions are 5 per cent below the level determined in the Kyoto Protocol baseline year of 1990. If participants fail to meet targets, they pay a penalty per tonne of emissions above their targets.

Abatement certificates are issued by accredited organisations for low-emission generation of electricity, reduced consumption of electricity and capture of carbon from the atmosphere by forests. Each certificate is equivalent to 1 tonne of CO₂ equivalent associated with the consumption of electricity. These schemes will continue until a national scheme is introduced.

A national response

The Australian Government has set a long-term goal of reducing carbon emissions to 60 per cent below 2000 levels by 2050. To help achieve this goal, in 2008 the Government proposed its Carbon Pollution Reduction Scheme to take effect in 2010. The scheme relies on emissions trading to encourage more efficient energy production and reduce greenhouse gas emissions. In its initial green paper, the Government proposed a limit (or cap) on the amount of carbon that firms can release. It would then provide a number of carbon ‘permits’ equal to the set limit. Companies would then be able to compete against each other to buy these permits. For some companies it would be cheaper to develop cleaner production technologies (or reduce emissions) than to buy the permits.

Related sites

• Carbon currency – the credits and debits of carbon emissions trading (Nova: Science in the news, Australian Academy of Science)

• Australian Government Department of Climate Change
  • Kyoto Protocol
  • Carbon pollution reduction scheme

• About greenhouse (Cooperative Research Centre for Greenhouse Accounting)

• Summary of the NSW Greenhouse Gas Reduction Scheme (NSW Government)

• ACT Greenhouse Gas Abatement Scheme (ACT Government)

Activities

• Australian Government Bureau of Meteorology
  • Climate change – students investigate natural and human activities that cause climate change.

• Metro magazine (Australia)
  • An inconvenient truth – provides a study guide to the movie of the same name.

• The Weather Makers (Australia)
  • Thinking about climate change: A guide for teachers and students – contains information and a range of activities relating to climate change.

• Project AIRE (United States Environmental Protection Agency, New England)
  • Climate and the greenhouse effect – students predict then measure the warming effect of sunlight.

• Science upd8 (UK)
  You need to register to access activities but they are free.
  • Global warming: Do 'the facts' stand up? – students interpret the iconic ‘hockey stick' graph, estimate when the Earth could be 1°C hotter, and defend challenges to their own conclusions.
  • Our atmosphere: Hottest investment – students familiarise themselves with climate change and the factors that prevent us from taking collective action to ameliorate the situation.
  • Climate change: What will you do? – students plan campaigns to get students and teachers at school to take action to combat climate change.

• Classroom of the Future (NASA, USA)
  • Fossil fuel burning – students compare the CO₂ released by fossil fuel burning to the actual increase in atmospheric CO₂.

• Xpeditions (National Geographic, USA)
  • Climate and CO₂: Analysing their relationship – students speculate on various scenarios of future world climates if the greenhouse effect increases.

• New York Times Learning Network (USA)
  • Clearing the air – students investigate emissions that contribute to global warming, and present to a mock international summit recommendations for reversing the global warming trend.
  • Ice breakers – students demonstrate several physical properties of ice, then relate these properties to the effects of global warming on icecaps.
  • Walking on thin ice? – students examine scientific evidence of changes in the Arctic ice cover.
  • Weathering the weather – students explore the effects of global warming on their community.
  • Tending to the greenhouse – students examine global warming – its causes, effects and solutions.

• University of Buffalo (USA)
  • The petition: A global warming case study – provides a case study and a series of questions. Case teaching notes are available.

• Global warming: Early warning signs (USA)
  • Curriculum guide for the climate impacts map – suggests four activities to use with a map (http://www.climatehotmap.org) that illustrates the local consequences of global warming.

• Check out the Activities at our topic on carbon emissions trading.

Activity 1. Temperature increases in a mini-greenhouse

Materials (for the class)

• 3 identical containers (eg, shoeboxes or 4-litre ice-cream containers)
• scissors
• sheet of clear plastic (approximately 15 centimetres × 15 centimetres)
• sheet of glass (approximately 15 centimetres × 15 centimetres)
• thermometer
• plasticine

Procedure

1. Cut out a large rectangle or square from the lid of each container.

2. Use sticky tape to fix a sheet of clear plastic over the opening in the lid of the first container.

3. Put a sheet of glass over the second container and leave the third one open.

4. Make a small hole through which a thermometer can be inserted in one side of each container.

5. Leave the containers in sunlight and record the temperature inside each container every 5 minutes for 20 minutes. (You can plug the hole for the thermometer with plasticine when you are not measuring the temperature.)

6. Graph the results and write a few lines about what you conclude from your results.

Teachers notes

If you have three thermometers, you can leave a thermometer in each box and record the three temperatures at 5-minute intervals. A different version of this activity can be found in Investigating (Australian Primary and Junior Science Journal), August 1997, pages 6-7.

Activity 2. Data on carbon dioxide emissions

1. Which of the five countries produces the greatest percentage of its CO₂ emissions from:
   1. industry;
   2. transport;
   3. agriculture;
   4. providing services;
   5. households?

2. Which country produces the lowest percentage of its CO₂ emissions from industry?

3. In which sector(s) should Australia try to reduce CO₂ emissions?

4. Much of the electricity consumed by Australian industry is used for processing metals (eg, we turn bauxite (an ore) into pure aluminium metal, which we export).
   1. If we exported the raw bauxite, what effect would this have on our CO₂ emissions?
   2. How is Australia advantaged by processing bauxite before it is exported; how is it disadvantaged?

Activity 3. Reducing greenhouse gas emissions

Working in groups of two or three, discuss the issues raised by the following questions and make brief notes of your views.

• Should we be taking action now to cut down on emissions of greenhouse gases, or should we wait until the full extent of global warming and climate change are known?

• What effects would reducing greenhouse gas emissions be likely to have on Australia's economy and on our standard of living?

• Is Australia a major contributor to the world's greenhouse gas emissions?

Further reading

• What is happening in the North Atlantic?
• The unique relationship between the sea and CO₂
• The strange world of oceanic methane

• Ice coring: a special selection
• Thermophilic bacteria in Lake Vostok
• The greenhouse phenomenon and climatic feedback

• Polar flora and fauna facing up to major climate warming
• The peoples of the Arctic, the first victims of global warming
• And what would happen if the Gulf Stream stopped?
• Ozone story
• Satellites at the service of polar research
• Permanent monitoring of the atmosphere from the Svalbard

Useful sites

The Australian Greenhouse Office (Commonwealth Government)

This site provides a range of information. For example, click on 'Emissions monitoring' for information about climate change and emissions projections and click on 'Government' for links to Australian initiatives to reduce greenhouse gas emissions.
http://www.greenhouse.gov.au/

The greenhouse effect (CSIRO Atmospheric Research, Australia)

Provides information about the major greenhouse gases and their likely affect on global climate.
http://www.cmar.csiro.au/e-print/open/holper_2001b.html

Climate literacy: The essential principles of climate sciences (US Climate Change Science Program) Presents principle facts about climate and climate change with supporting information for each principle.

Understanding and responding to climate change (The National Academies, USA) Highlights known facts about climate change, its impacts, required areas of research and ways of preparing for it.

Introduction to global warming (Encyclopedia of the Atmospheric Environment, UK)

A general explanation of the causes and consequences of global warming. Highlighted words link to more detailed articles on specific topics.
http://www.ace.mmu.ac.uk/eae/Global_Warming/Older/Global_Warming_Introduction.html

Maps and graphics (United Nations Environment Progamme GRID Arendal)

Provides a wide range of graphics showing the impact of climate change, including changes to temperature, rainfall and crop production, as well as the impact on natural disasters, sea level, disease and wildlife.
http://maps.grida.no/go/searchFree/q/climate

Royal Society, UK

• Facts and fictions about climate change
  Examines twelve arguments put forward by opponents of urgent action on climate change, using scientific evidence to identify flaws in the arguments.
  http://www.royalsociety.org/page.asp?id=4761

• Climate change – in my view
  Five members of the Royal Society present their views on climate change.
  http://www.royalsoc.ac.uk/page.asp?id=4607

Greenhouse Gas Online (UK)

Provides links to current news items about different aspects of the enhanced greenhouse effect.
http://www.ghgonline.org

Climate change (Met Office, UK)

This site provides a range of information on climate change including climate change science, a guide to the facts and impacts and history of climate change, and the annual United Nations climate change conference.
http://www.metoffice.gov.uk/climatechange/

Global climate change: Research explorer (Exploratorium, USA)

Provides information about the physical processes underlying our climate and the kinds of data needed to determine how the climate is changing. This primer is organised into four interconnected sections – the atmosphere, the hydrosphere, the cryosphere and the biosphere.
http://www.exploratorium.edu/climate/index.html

American Institute of Physics, USA

• Timeline of milestones
  Provides a timeline of important dates in the discovery of global warming.
  http://www.aip.org/history/climate/timeline.htm

• The discovery of global warming
  Follows the change in scientific thinking during the 20th century leading to the discovery of rapid climate change.
  http://www.aip.org/history/climate/

Climate change science: An update of current understanding and uncertainties (Australian Academy of Technological Sciences and Engineering)

Summarises the outcomes of a 2002 workshop on post-1995 changes in the understanding of climate change science.
http://www.atse.org.au/index.php?sectionid=469

Australian Broadcasting Corporation

• Why we must act now to reduce greenhouse gas emissions (In Depth, 25 November 2009)
  An explanation from Australia’s Chief Scientist of the enhanced greenhouse effect and the potential effects on Australia if greenhouse gas emissions aren’t reduced.
  http://www.abc.net.au/science/articles/2009/11/25/2753561.htm

• The global warming debate (Ockham’s Razor, 18 May 2008)
  http://www.abc.net.au/rn/ockhamsrazor/stories/2008/2249809.htm

• Next decade may be cooler, not warmer (News in Science, 1 May 2008)
  http://www.abc.net.au/science/articles/2008/05/01/2232561.htm?site=science&topic=latest

• It's easy being greener (The Lab, 19 October 2006)
  Tells how to make a few simple changes to have a big impact on climate change.
  http://www.abc.net.au/science/features/greener/

• Study clears sun of climate change (News in Science, 14 September 2006)
  Reports on a study that weakens claims that climate change is due to natural sunspot cycles.
  http://abc.net.au/science/news/stories/2006/1740858.htm

• The business of climate change (Background Briefing, 16 October 2005)
  http://www.abc.net.au/rn/talks/bbing/stories/s1480714.htm

• Soil may belch out CO₂ to warm planet (News in Science, 8 September 2005)
  http://www.abc.net.au/science/news/stories/s1455886.htm

• Planet slayer: Prof. Schpinkee's greenhouse calculator
  Use Prof Schpinkee's greenhouse calculator to work out how much of an environmental pig you are, and how long you should live. Also supplies a 'science behind the answers' explanation to each question.
  http://www.abc.net.au/science/planetslayer/greenhouse_calc.htm

• International climate taskforce (Earthbeat, 20 November 2004)
  Earthbeat looks at the business case for acting on climate change and forecasts a spike in global grain prices will force people into action.
  http://www.abc.net.au/rn/science/earth/stories/s1247176.htm

• The tree totaller (Earthbeat, 5 June 2004)
  A new household greenhouse gas calculator aims to help plant more trees to soak up dangerous emissions.
  http://www.abc.net.au/rn/science/earth/stories/s1124875.htm
  

• Crystal ball climate change (The Lab, 22 April 2004)
  A good summary of many of the consequences of global warming. Includes a list of links to other Australian Broadcasting Corporation articles on climate change.
  http://abc.net.au/science/features/climatechange

Glossary

chlorofluorocarbons (CFCs). Organic compounds made up of atoms of chlorine, fluorine and carbon. They were commonly used as refrigerants in refrigerators and air conditioners, as blowing agents in foam plastics, and as cleaners for computer circuit boards. CFCs do not occur naturally – their increase in the atmosphere is entirely the result of human activity. Beginning in the 1940s there was a rapid increase in the rate of manufacture, and hence the escape, of CFCs. The realisation that they were responsible for ozone depletion in the stratosphere has led to their phasing out under the 1987 Montreal Protocol.

Conference of the Parties (COP). Comprises all countries that have ratified the United Nations Framework Convention on Climate Change. COP is responsible for implementing the objectives of the Convention and has been meeting regularly since 1995. More information can be found at Conference of the Parties (COP) (United Nations Environment Programme).

El Niño-Southern Oscillation (ENSO). A sporadic climatic phenomenon that occurs because of changes in the usual atmospheric pressure patterns and in the sea surface temperature in parts of the Pacific Ocean. The results include the substantial reduction of the normal upwelling off the Peruvian coast, failure of the anchovy fishery in the same area, excessive rain in western South America, and droughts in Australia and parts of Indonesia.

enhanced greenhouse effect. An increase in the natural process of the greenhouse effect, brought about by human activities, whereby greenhouse gases such as carbon dioxide, methane, chlorofluorocarbons and nitrous oxide are being released into the atmosphere at a far greater rate than would occur through natural processes and thus their concentrations are increasing. Also called anthropogenic greenhouse effect or climate change.

global warming. An increase in the average temperature of the Earth's surface. Global warming is one of the consequences of the enhanced greenhouse effect and will cause worldwide changes to climate patterns.

greenhouse effect. The trapping and build-up of heat in the lower atmosphere near a planet's surface. Some of the heat flowing back towards space from the Earth's surface is absorbed by water vapour, carbon dioxide, methane and other gases in the atmosphere. If the atmospheric concentration of these gases rises, then theory predicts that the average temperature of the lower atmosphere will gradually increase. The greenhouse effect in part explains the temperature differences of Mars, Venus and Earth.

halocarbons. Compounds of carbon combined with one or more of the elements called halogens (fluorine, chlorine, bromine, iodine, and astatine). Halocarbons containing fluorine, chlorine and bromine contribute to ozone depletion and to the enhanced greenhouse effect.

Kyoto Protocol. The third session of the Conference of the Parties to the UN Framework Convention on Climate Change took place in Kyoto, Japan in December 1997, resulting in the Kyoto Protocol. This working agreement of the signatories commits developed countries to reduce their collective emissions of six greenhouse gases by at least 5 per cent of 1990 levels by 2012. The Kyoto agreement became legally binding on 16 February 2005 when 132 signatory countries agreed to strive to decrease carbon dioxide emissions. More information can be found at the official The Kyoto Protocol site.

Montreal Protocol. An intergovernmental document signed by many countries in 1987 (and regularly revised) which established restrictions for the manufacture and use of ozone-depleting substances in an international effort to reduce ozone depletion. The text of the Protocol with the 1990 and 1992 amendments is available.