The programme claimed to lay bare all the fallacies that have created the "great myth" that is man-made global warming. However, the programme itself was riddled with holes. We mention a few of these issues below, and provide links to other websites that have done a good job of outlining the programme's flaws.
As New Scientist's editor, Jeremy Webb, put it: previously climate sceptics were seen to deconstruct the arguments of climate change scientists. What was different about last week's documentary was that it constructed a complete argument to explain why our planet's climate is changing - in essence, variations in solar activity.
A FEW QUICK POINTS ON ERRORS MADE IN THE PROGAMME:
1) Volcanoes do not emit more carbon dioxide than human activities combined. If they did, the curve showing the rise in atmospheric concentrations of carbon dioxide would be punctured by irregular jumps, representing each volcanic eruption. Instead, it's smooth.
2) The latest IPCC report
shows that the combined warming impact - of all human activities, is roughly ten times that of natural factors, namely solar irradiance. See the bar chart here .
3) The period of cooling between 1940 and 1970, which the film claimed was proof that the global warming hypothesis is flawed, has a simple and proven explanation.
......It was caused by industrial sulphate emissions, combined with a cluster of volcanic eruptions
, which also emit sulphates. The industrial sulphates have since been partially cleaned up thanks to clean air laws adopted in developed countries.
This figure , published by Gerald Meehl
of the National Center for Atmospheric Research
in 2004, shows how climate models can reconstruct 20th century temperatures, including the mid-century cooling, using different factors that contribute to both warming and cooling global temperatures.
One of the scientists (Carl Wunsch) who contributed to the film has complained very openly about how his interview was distorted. You can find his complaints here and here . This is a quote from the letter he wrote in the UK daily The Independent:
In the part of The Great Climate Change Swindle 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.
For more about the programme's flaws see:
• RealClimate (a blog run by climate scientists: "it just repeated the usual specious claims we hear all the time")
• Steve Connor's article in The Independent ("graphs used were distorted, mislabelled or just plain wrong")
• an interesting entry on the progamme's director, Martin Durkin, on Wikipedia ("he has caused consistent controversy over the alleged bias found in many of his documentaries").
SOURCE: Climate change: who is swindling who?
Impressive presentation does not necessarily reflect reality. This producer seems to make his living from presenting sensational, but “dubious” data. Above is a Wiki link to Durkin, but this one I found impressive: ( Monbiot.com » Modified Truth Durkin presented on Channel 4 a documentary that showed silicone breast implants are safe and even reduce the breast cancer risk.
I have not seen a good reference linking sunspot activity to measurable solar output (the technical term is "solar irradiance"). If true, this should have been easy. Sunspot activity has been correlated with economic growth, and crop yields – but not increased solar irradiance.
I chased down a little of the 'solar output is increasing' and all said that the output increase does not account for the warming we have seen (see below).
I have been studying through RealClimate for a year now, and am always impressed with the scholarship. Although somewhat technical, I have consistently found it informative to slog through cross-reference the concepts presented. Here is the RealClimate take on the program.
As I see it, the bottom line is:
Argument over causation is interesting but irrelevant.
CO2 and methane do influence temperature.
Putting more up will increase temperature.
Temperatures do change - as does species composition on earth.
It just kinda sucks when yours is at risk.
Below are papers on solar irradiance
Pattern of Strange Errors Plagues Solar Activity and Terrestrial Climate Data
Eos,Vol. 85, No. 39, 28 September 2004
Analysis of a number of published graphs that have played a major role in these debates and that have been claimed to support solar hypotheses [Laut, 2003; Damon and Peristykh, 1999, 2004] shows that the apparent strong correlations displayed on these graphs have been obtained by incorrect handling of the physical data.
......These findings do not by any means rule out the existence of important links between solar activity and terrestrial climate. ... The sole objective of the present analysis is to draw attention to the fact that some of the widely publicized, apparent correlations do not properly reflect the underlying physical data.
Science 15 September 2006:
Vol. 313. no. 5793, p. 1543
Editors' Choice: Highlights of the recent literature
Satellite measurements show that solar irradiance, essentially the amount of energy that reaches Earth, varies over the 11-year solar cycle by ~0.1%, too small a change to have a noticeable impact on Earth's average temperature. However, a long-standing question in climate science is whether larger solar changes have occurred that might have caused warming over the past century or climate change at some stage of the Holocene (or an even longer span of time).
......Bard and Frank provide a thorough critical review of both the problematic evidence for longer changes in solar irradiance and the possible climatic effects these changes could have induced. The authors point out that many proposed connections, for example between the records of cosmogenic nuclides such as 14C and 10Be and records of climate change, are based on correlations--some of which have large and perhaps unappreciated uncertainties--and on imperfect and indirect records.
......They conclude that there might still be a connection between solar changes and the Medieval Warm Period and Little Ice Age, but that overall solar changes, most of which remain unproven, probably represent a second-order influence on the behavior of Earth's recent climate.
Earth Planet. Sci. Lett. 248, 1 (2006).
Science 1 October 2004:
Vol. 306. no. 5693, pp. 68 - 69
A Stellar View on Solar Variations and Climate
Peter Foukal, Gerald North, Tom Wigley
......Accurate reconstruction of solar irradiance variations is important for assessing human and natural contributions to climate change. Fluctuations in the Sun's brightness, measured directly by space-borne radiometry over the past two 11-year sunspot cycles, seem too small to drive climate. Recent reconstructions of solar irradiance extending back to the 17th century have assumed that larger, multidecadal irradiance variations occur, similar to those detected on other Sun-like stars. In their Perspective, Foukal et al. discuss the recent retraction of this stellar evidence and of the solar irradiance reconstructions based on it, which has important implications for the relative roles of various forcing factors in climate change.
Solar influence on climate during the past millennium: Results from transient simulations with the NCAR Climate System Model
PNAS | March 6, 2007 | vol. 104 | no. 10 | 3713-3718
......The potential role of solar variations in modulating recent climate has been debated for many decades and recent papers suggest that solar forcing may be less than previously believed. Because solar variability before the satellite period must be scaled from proxy data, large uncertainty exists about phase and magnitude of the forcing.
......We used a coupled climate system model to determine whether proxy-based irradiance series are capable of inducing climatic variations that resemble variations found in climate reconstructions, and if part of the previously estimated large range of past solar irradiance changes could be excluded. Transient simulations, covering the published range of solar irradiance estimates, were integrated from 850 AD to the present. Solar forcing as well as volcanic and anthropogenic forcing are detectable in the model results despite internal variability. The resulting climates are generally consistent with temperature reconstructions.
......Smaller, rather than larger, long-term trends in solar irradiance appear more plausible and produced modeled climates in better agreement with the range of Northern Hemisphere temperature proxy records both with respect to phase and magnitude. Despite the direct response of the model to solar forcing, even large solar irradiance change combined with realistic volcanic forcing over past centuries could not explain the late 20th century warming without inclusion of greenhouse gas forcing.
......Although solar and volcanic effects appear to dominate most of the slow climate variations within the past thousand years, the impacts of greenhouse gases have dominated since the second half of the last century.
[Proofreader's note: this article was edited for spelling and typos on March 23, 2007]
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