Great Global Warming Swindle
According to “The Great Global Warming Swindle”, produced by Martin Durkin and broadcast on the UK Channel 4 in March 2007, human-triggered climate change is merely a conspiracy theory, designed by over 2000 climate scientists, the world’s leading climate research organizations and the Intergovernmental Panel for Climate Change to prevent the world’s poor nations from developing.
Given an overwhelming agreement among climate scientists and biologists about the reality of human-induced climate change, “climate sceptics”—some of whom are known to have received money from fossil fuel companies—have attempted to argue that (1) No global warming is taking place, or (2) If global warming is real it is of natural origins and not the result of human emissions, and may even be beneficial.
On 4 November 2006, Bob Ward, of the British Royal Society, wrote an extraordinary letter in the Annals of Science, addressed to a major oil company, stating, among other things, “… I am writing to express my disappointment at the inaccurate and misleading view of the science of climate change that these documents present.…leaves readers with such an inaccurate and misleading impression of the evidence on the causes of climate change that is documented in the scientific literature… My analysis indicates that [your company] provided more that $2.9 million to organizations in the United States which misinformed the public about climate change through their websites.”
The film “The Great Global Warming Swindle”, screened in Australia on the ABC on 12 July 2007, is no exception. It presents outdated temperature and solar irradiation plots which do not include changes recorded since the 1980s—omitting the critical evidence for greenhouse-driven climate change.
The film continues to perpetrate a number of discredited misconceptions:
- Misconception #1 - High temperatures are not unique to the twentieth and twenty-first centuries
By 2000 mean global temperatures had risen about 0.3ºC higher than the maximum of the Medieval Warm Period (1000-1200 AD) —the highest since 125,000 years ago when temperatures reached 2-3ºC above present levels. Temperature rise rates during 1970-2003 have exceeded those of the last glacial termination by an order of magnitude.
- Misconception #2 - CO2 is not the main cause of global warming
The triggers for ice age terminations originated with the sun, whereas the current climate change is caused by anthropogenic increase in emissions. The infrared radiative effects of CO2 are a physical fact demonstrated both in nature and in the laboratory, where the doubling of CO2 levels results in an increase of about 3ºC in temperature (Climate sensitivity). Rates of CO2 rise during 1970-2003 exceeded those of the last glacial termination by two orders of magnitude.
- Misconception #3 - During the interglacial periods changes in CO2 lag behind temperature rises, so are not the cause for warming
Past interglacial warming were triggered by sharp spikes in solar irradiation associated with the Earth’s position relative to the sun (Milankovic cycles), with consequent feedback release of greenhouse gas (CO2, CH4) from the oceans and the biosphere, resulting in atmospheric infrared radiation effects and in melting of ice sheets, which amplify global warming. By contrast current climate change is caused by the thermal effects of CO2 emissions from burning of some 300 billion tons of fossil fuel since the dawn of the industrial age, with consequent increase of CO2 to 380 parts per million, 36 percent above the maximum levels (about 280 parts per million) which pertained over the last one million years (the Pleistocene).
- Misconception #4 - No perfect concordance occurs between greenhouse gases and temperatures since the down of the industrial age.
Terrestrial mean temperature variations are a compound consequence of several factors, principally solar variations and greenhouse gases. Since the beginning of the twentieth century to about 1940 temperatures increased by about 0.45ºC as a combined effect of an increase in greenhouse emissions and in solar irradiation associated with the eleven-year sunspot cycle (Figure 1). A decline in temperature during 1940-1970 of about 0.1ºC occurred, despite continuing rise in emissions, due to aerosol reflectance effects and a decline in the sun spot cycle. From the mid-1970s the solar cycle effects and temperature effects were strongly decoupled due to sharp rise in greenhouse gas levels, rising by about 0.6ºC to 2000.
- Misconception #5 - Cosmic rays result in increased clouding; consequently periods of low cosmic ray flux cause global warming.
The cosmic ray flux and solar irradiance are inversely related, due to deflection of the former during periods of maximum sun spot activity. Water clouds have both cooling effects (due to reflection) and warming effects (due to infrared properties of water). The increased clouding during periods of cosmic ray maxima and sun spot minima may ensue from decreased solar radiation and lesser cloud dispersion. It has not been demonstrated that cosmic rays result in cloud nucleation. Cloud formation is affected by several factors, including concentration of aerosols and dust, and is relatively scarce over areas of maximum warming, namely the poles and the deserts. From the mid-1970s temperatures were strongly decoupled from the solar and cosmic ray cycles.
- Misconception #6 - Water vapour is responsible for global warming
Increases in evaporation and concentration of water vapour in the atmosphere are the consequence of, not the trigger for, global warming. The water contents of the atmosphere over desert and polar regions, subject to maximum warming, is low to very low. The residence time of water in the atmosphere is much shorter than that of CO2, which may last between 5 and 200 years.
- Misconception #7 - Ice sheet melting effects are slow processes lasting many centuries or millennia.
Long-term relations between sea level rise and temperatures exceed 4 meters per 1ºC. Significant short-term (decades to century-scale) temperature and sea levels fluctuations (several degrees and many meters) during the last ice age (about 110–15 thousand years ago) imply great instability of the Greenland and west Antarctic ice sheets. Marked reduction in permanent ice cover by about 17 percent, and rapid collapse dynamics of these ice sheets, were observed over the last 20 years. Sea levels rise rates have doubled between 1860 and 2005 (1860-2000 +1.6 mm/year; 1910-1997 +2.3 mm/year; 1994-2005 +2.8 to 3.4 mm/year).
According to the World Conservation Union, present extinction rates are 50 to 500 times the natural background rate and up to 52 percent of species are threatened with extinction (http://www.iucn.org/themes/ssc/index.htm). Great mass extinction of species during geological history (late Devonian, Permian-Triassic, end-Triassic, Cretaceous-Tertiary, Paleocene-Eocene) have been triggered by volcanic, asteroid impact and greenhouse events associated with sharp increases in atmospheric levels of CO2 and CH4. The disinformation and obfuscation inflicted by vested interests and their mouthpieces have already cost the world at least ten years delay in advancing effective countermeasures to climate change. Those who watched “The Great Global Warming Swindle” need to bear these points in mind.
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