The Great Global Warming Swindle - Debunked!

In March 2007, Channel Four screened a film entitled "The Great Global Warming Swindle". With convincing-looking charts and appearances from numerous talking heads, the film set out to show that man-made climate change is a myth, perpetrated by governments seeking an excuse to raise taxes, environmental extremists seeking to take ever more extreme positions and climate change researchers seeking their next grant.

Whilst initally very convincing, a little research shows that the film is inaccurate, misleading, and little more than a propaganda piece.

Martin Durkin has a reputation for producing misleading anti-environment programmes.
Many of the participants, whilst presented as climate scientists, have little or no relevant scientific qualification, and have never published peer-reviewed papers on climate science. Some have been shown to have links with climate sceptic lobby groups funded by big business.
The theory presented, that sunspot activity has more effect on our climate than greenhouse gasses do, was disproved several years ago.
The period of "global cooling" which followed the Second World War does not demonstrate that global warming is not caused by human CO₂ emissions, rather it was caused by increased atmospheric pollution, and was merely masking the global warming effect of CO₂.
Climate change campaigners are not seeking to keep the developing world in poverty. Rather, we are calling for a more equitable world via Contraction and Convergence.

The participants
The link between solar activity and temperature
The link between CO₂ and temperature
Global cooling
Water vapour
Contraction and Convergence
Further reading
Take action!

The participants

Martin Durkin

Martin Durkin has a history of making controversial and misleading programmes with a bias against environmentalists. In 1998 his Channel Four series "Against Nature" was the subject of a complaint by Friends of the Earth. The complaint was upheld by the Independent Television Commission, who said in their ruling that the programme makers "distorted by selective editing" the views of FoE Campaigns director Tony Juniper and other interviewees and "misled" participants over the "content and purpose of the programmes when they agreed to take part". In addition, the series came under fire from George Monbiot for its factual errors and misrepresentation of the environmental movement.

Professor Carl Wunsch - distortion by selective editing

Distortion by selective editing was also used in the Great Global Warming Swindle. Oceanographer Carl Wunsch responded angrily to the way his comments had been edited into the film. In his public response, he said

In the part of the "Swindle" film where I am describing the fact that the ocean tends to expel carbon dioxide where it is warm, and to absorb it where it is cold, my intent was to explain that warming the ocean could be dangerous---because it is such a gigantic reservoir of carbon. By its placement in the film, it appears that I am saying that since carbon dioxide exists in the ocean in such large quantities, human influence must not be very important --- diametrically opposite to the point I was making--- which is that global warming is both real and threatening in many different ways, some unexpected.

Writing to Wag TV, the production company, the Professor said

I am shown explaining that a warming ocean could expel more carbon dioxide than it absorbs -- thus exacerbating the greenhouse gas buildup in the atmosphere and hence worrisome. It was used in the film, through its context, to imply that CO2 is all natural, coming from the ocean, and that therefore the human element is irrelevant. This use of my remarks, which are literally what I said, comes close to fraud.

I have some experience in dealing with TV and print reporters and do understand something of the ways in which one can be misquoted, quoted out of context, or otherwise misinterpreted. Some of that is inevitable in the press of time or space or in discussions of complicated issues. Never before, however, have I had an experience like this one. My appearance in the "Global Warming Swindle" is deeply embarrasing, and my professional reputation has been damaged. I was duped---an uncomfortable position in which to be.

Questionable credentials

Eight of the talking heads appearing in the film are known to be linked to organisations with an anti-environment or pro-business agenda, as shown by this map on the Exxon Secrets web site. Exxon Secrets is a site dedicated to tracking the links between climate change sceptics and lobby groups which have received funding from the oil giant Exxon Mobil, widely regarded as the world's number one climate criminal for its refusal to invest in renewable energy.

This post on the Climate Change Denial blog sheds some light on some of the contributors to the film.

Of Fred Singer, it says

Despite the caption on the programme, Singer has retired from the University of Virginia and has not had a single article accepted for any peer-reviewed scientific journal for 20 years. His main work has been as a hired gun for business interests to undermine scientific research on environmental and health matters. Before turning to climate change denial he has argued that CFCs do not cause ozone depletion and second hand smoke does not cause cancer.

Of Patrick Michaels, it says

Patrick Michaels is the most prominent US climate change denier. In the programme he claimed “I’ve never been paid a nickel by the old and gas companies” which is a curious claim. According to the US journalist Ross Gebspan Michaels has received direct funding from, among others German Coal Mining Association ($49,000), Edison Electric Institute ($15,000), and the Western Fuels Association ($63,000) an association of US coal producing interests.

Of Philip Stott, it says

Philip Stott was captioned as a Professor at the University of London although he is retired and is therefore free of any academic accountability. Stott is a geographer by training and has no qualifications in climate science. Since retiring Stott has aimed to become Britain’s leading anti-green pundit dedicating himself to wittily criticizing rainforest campaigns (with Patrick Moore), advocating genetic engineering and claiming that "global warming is the new fundamentalist religion."

Of Patrick Moore, it says

Patrick Moore is Stott’s Canadian equivalent. Since a very personal and painful falling out with Greenpeace in 1986 Moore has put his considerable campaigning energies into undermining environmentalists, especially his former friends and colleagues. Typical of his rhetoric was his claim in the programme that environmentalists were “anti-human” and “treat humans as scum”. Throughout the 1990s Moore worked as lead consultant for the British Columbian Timber Products Association undermining Greenpeace’s international campaign to protect old growth forest there.

Of Peirs Corbyn, it says

Piers Corbyn has no academic status and his role in such programmes is to promote his own weather prediction business. He has steadfastly refused to ever subject his climatological theories to any form of external review or scrutiny.

Of Tim Ball, it says

Tim Ball was captioned as the University of Winnipeg. In fact he left in 1996 since when he has run political campaigns through two organisations he helped found: the Natural Resources Stewardship Project and the Friends of Science which, according to their websites aim to run "a proactive grassroots campaign to counter the Kyoto Protocol"; and "encourage and assist the Canadian Federal Government to re-evaluate the Kyoto Protocol".

Already, the contributors to the film, or the way their contributions were used, is looking questionable. But the science is also flawed.

The link between solar activity and temperature

The Great Global Warming Swindle makes the case that the current widely-believed theory that anthropogenic greenhouse gas emissions are causing a change in the climate, is wrong, and that global temperature is entirely caused by sunspot activity.

Cloud formation, their counter-theory goes, is driven by so-called cosmic rays - subatomic particles emitted by supernovae. When these particles reach the Earth's atmosphere, they encounter water vapour, causing it to condense, so clouds form. Clouds have a cooling effect on the Earth by blocking some of the sun's rays. Meanwhile, increased sunspot activity causes the solar wind - charged particles emitted by the sun - to increase, and this has the effect of "blowing" more of the cosmic rays away from the Earth, so fewer clouds form, and the global temperature rises because more of the sun's rays can get through.

The RealClimate blog has this to say on the link between cosmic rays and cloud formation: Taking Cosmic Rays for a Spin

The working hypothesis of the cosmic ray crowd is that the (weak) correlations between low clouds and cosmic rays are causal (i.e. a cosmic ray increase - due to a solar magnetic field weakening - causes low clouds to increase, cooling the planet). The 'spin' on this new paper is that this has been demonstrated, and is significant, and furthermore, is responsible for the 20th Century rise in global temperatures. But let's look carefully at what is required in this logic:

First, the particles observed in these experiments are orders of magnitude too small to be Cloud Condensation Nuclei (CCN). In the press release, this is why they talk about the 'building blocks' of CCN, however, aggrandisation of these small particles is in no sense guaranteed (Missing step #1). Secondly, the focus is on low clouds over the ocean. However, over the ocean, there are huge numbers of condensation nuclei related to sea salt particles. Thus to show that the cosmic ray mechanism is important, you need to show that it increases CCN even in the presence of lots of other CCN (Missing step #2). Next, even if more CCN were made, you would need to show that this actually changed cloud cover (or optical thickness etc.) (Missing step #3). And given that change in cloud properties, you would need to show that it had a significant effect on radiative forcing - which despite their hand waving, is not at all well quantified (even the sign!) (Missing step #4). Finally, to show that cosmic rays were actually responsible for some part of the recent warming you would need to show that there was actually a decreasing trend in cosmic rays over recent decades - which is tricky, because there hasn't been (see the figure) (Missing step #5). All of this will require significant work and there are certainly no guarantees that all the steps can be verified (which they have been for the greenhouse gas hypothesis) - especially the last! However, they would seem essential to justifying the claims in the press releases.

To back up the correlation between sunspot activity and global temperature, the Great Global Warming Swindle uses a graph very similar to this one, taken from the paper entitled "Pattern of Strange Errors Plagues Solar Activity and Terrestrial Climate Data" by Paul Damon, University of Arizona, Tucson and Peter Laut, Technical University of Denmark, Lyngby.

This appears to provide convincing evidence that recent global warming is entirely due to sunspots, until you take into account that the most recent data points on the blue line representing solar activity were not measured in a consistent way with the rest of the points on that line, and have since been shown to be inaccurate. As that paper explains, most of the data which makes up the blue line was heavily smoothed to remove short-term variations and provide a clearer line, however the four most recent points were from a different data set which was not smoothed at all. The reasoning behind adding these four points was that the observational data necessary to perform the smoothing was not available in 1991, the time of publication.

This is a scientifically flawed approach. The correct approach would be to leave out the newer, unsmoothed, data entirely, and work only with data gathered in a consistent manner. In layman-speak, this is like comparing apples with oranges.

In 2004, with more observational data available, those four points could be plotted more accurately, and once handled properly, the apparent rise in sunspot activity in recent decades goes away, as shown in this graph, taken from the same paper. This was known to the scientific community for at least two years before the Great Global Warming Swindle was made.

So there has been a rise in global temperature in recent decades, and although there has been a strong correlation between sunspot activity and global temperature over century timescales, it does not account for the recent temperature rise. The theory that global temperature is solely caused by sunspots therefore falls.

Clearly it would be crazy to claim that the sun has no effect on our climate, after all the sun is the energy source which drives everything on our planet, however it would be equally crazy to claim that the sun is the sole factor determining our climate. Many other factors need to be taken into account, and greenhouse gasses produced by human activity are still very much in the frame.

The link between CO₂ and global temperature

The Great Global Warming Swindle relied heavily on trying to disprove the effect of levels of carbon dioxide in the atmosphere on temperature. It started by misrepresenting the position of the human-induced climate change camp on the relationship between CO₂ levels and temperature. Contrary to the claims made in the film, nobody is seriously claiming that temperature is caused solely by CO₂ levels. It is equally wrong to claim, as the film did, that CO₂ levels are caused solely by temperature. It is a complex feedback relationship, with cause and effect running in both directions.

If the the greenhouse effect theory is correct, then increased levels of CO₂, and other greeenhouse gasses such as methane and nitrous oxide, will lead to a rise in temperature as heat radiated from the Earth is trapped in the atmosphere. Meanwhile, as global temperature rises, more greenhouse gas is emitted into the atmosphere. This is the real danger of climate change - if a positive feedback cycle is established, with more greenhouse gasses causing the temperature to rise, causing more greenhouse gasses to be emitted, then we enter the scenario of runaway climate change.

One natural source of greenhouse gas is the ocean. As Professor Carl Wunsch tried to explain in his interview for the Great Global Warming Swindle, carbon dioxide dissolves in water. The colder the water, the more carbon dioxide it can hold. It follows, then, that if the ocean warms up, it will expel some of the dissolved carbon dioxide into the atmosphere. The sheer vastness of the ocean and the amount of carbon dioxide it holds, means that it poses a significant danger of causing runaway climate change if it warms up too much.

The film also made much of the 800-year time lag between temperature changes and CO₂ levels over the beginning and end of ice ages, putting it forward as proof that temperature causes CO₂ levels and not vice versa. The RealClimate blog poses the question "What does the lag of CO2 behind temperature in ice cores tell us about global warming?" and explains that warming at the end of an ice age takes around 5000 years, so the 800-year lag only shows that CO₂ did not cause the first 800 years of warming, but that the other 4200 years could be caused by CO₂. It continues:

From studying all the available data (not just ice cores), the probable sequence of events at a termination goes something like this. Some (currently unknown) process causes Antarctica and the surrounding ocean to warm. This process also causes CO₂ to start rising, about 800 years later. Then CO₂ further warms the whole planet, because of its heat-trapping properties. This leads to even further CO₂ release. So CO₂ during ice ages should be thought of as a "feedback", much like the feedback that results from putting a microphone too near to a loudspeaker.

In other words, CO₂ does not initiate the warmings, but acts as an amplifier once they are underway. From model estimates, CO₂ (along with other greenhouse gases CH₄ and N₂O) causes about half of the full glacial-to-interglacial warming.

Global cooling

In the 1970s, rather than the global warming now being predicted, it was believed that atmospheric pollution was causing global cooling, and that we might be looking at a man-made ice age. Now, several decades later, environmentalists are saying that human activity is causing global warming instead. The person in the street could be forgiven for being sceptical over this-about face. So which is true?

They both are.

Global cooling is caused by aerosols in the atmosphere. The RealClimate blog describes aerosols as:

solid or liquid particles suspended in the atmosphere, consisting of (in rough order of abundance): sea salt, mineral dust, inorganic salts such as ammonium sulfate (which has natural as well as anthropogenic sources from e.g. coal burning), and carbonaceous aerosol such as soot, plant emissions, and incompletely combusted fossil fuel.

It continues:

As should be apparent from this list, there are many natural sources of aerosol, but changes have been observed in particular, in the atmospheric loading of carbonaceous aerosol and sulphates, which originate in part from fossil fuel burning. While a relatively minor part of the overall aerosol mass, changes in the anthropogenic portion of aerosols since 1750 have resulted in a globally averaged net radiative forcing of roughly -1.2 W/m², in comparison to the overall average CO₂ forcing of +1.66 W/m².

In plain English, this means that whilst burning fossil fuels has increased the amount of CO₂ in the atmosphere, causing a tendency towards warming, it has also increased the amount of aerosols in the atmosphere, having a cooling effect which masks three quarters of the warming caused by the CO₂.

The Great Global Warming Swindle uses a graph showing a reduction in global temperature in the decades following 1940, a period which conicides with the post-war consumer boom, increased indistrialisation and increased CO₂ emissions. Therefore, the film concludes, CO₂ cannot be the cause of global warming.

On the contrary, global warming and global cooling were both happening at the same time, largely cancelling each other out. Stricter controls over pollution in recent decades have reduced the amount of aerosols being added to the atmosphere, whilst not reducing the CO₂ emissions. With fewer aerosols to mask the warming effect caused by the CO₂, the world is once again warming.

The RealClimate blog also highlights a warning about aerosols and CO₂:

The relative lifetimes of CO₂ and aerosol in the atmosphere result in the expectation that reducing fossil fuel use will accelerate warming. A CO₂ molecule has a lifetime of about 100 years in the atmosphere, while an aerosol particle has an average life expectancy of only about 10 days. Therefore, if we instantaneously ceased using combustion engines, the (cooling) fossil fuel-related aerosols would be cleaned out of the atmosphere within weeks, while the (warming) CO₂ would remain much longer, leaving a net positive forcing from the reduction in emissions for a century or more.

Water Vapour

The Great Global Warming Swindle states that water vapour accounts for 95% of the greenhouse gasses in the atmosphere, and argues that therefore any man-made CO2 emissions are so small by comparison as to be insignificant to climate change. The RealClimate blog addresses the issue of water vapour and its role in the greenhouse effect, in the post entitled "Water vapour: feedback or forcing?"

Yes, water vapour is a greenhouse gas, in that it absorbs long-wave radiation emitted by the planet, and radiates some of it back to the planet, but as with CO2, the relationship between water vapour and temperature is not one-way. More water vapour in the atmosphere strengthens the greenhouse effect, and meanwhile higher temperatures shift the balance between liquid water and water vapour due to evaporation. Water vapour on its own does not cause climate change, but it amplifies any man-made climate change.

The relationship between water vapour and climate change is further complicated by the fact that more water vapour is likely to mean more clouds, having a cooling effect.

Contraction & Convergence

The final section of the film focussed on the developing world. Showing the hardship and poverty experienced by millions in Africa, it implied that advocates of man-made global warming have a hidden agenda to keep the developing world in poverty, whilst continuing to enjoy the benefits of living in the developed world.

On the contrary, the policy regarding the developing world which most climate change campaigners advocate is one of Contraction and Convergence - that is, the countries with the highest per capita greenhouse gas emissions reduce their emissions to a more sustainable level (Contraction), whilst allowing the developing world a slight increase in per-capita greenhouse gas emissions to the same level (Convergence).

Contraction and Convergence is explained in more detail at the web site of the Global Commons Institute, the body which drew up the concept, and also in this New Scientist article from 2003.

Take action!

You can submit a complaint to Channel 4 about the Great Global Warming Swindle, via their web site.

You can also submit a complaint to Ofcom , the regulatory body, via their web site.

Last Modified 5/7/07 11:09 AM

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