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The climate change catastrophe

The first climate change catastrophe is the failure of climate scientists to win a near-unanimous victory in the court of public opinion.  They have allowed people who deny the influence of human activity on global warming to sway the opinion of sufficient numbers of people, business leaders, and politicians to prevent significant action to reduce greenhouse gas emissions.

For example, the erroneous but powerful claim that there has been no warming since 1998 while carbon dioxide emissions have risen and therefore rising carbon dioxide does not lift temperature has not been convincingly rebutted by climate scientists.

There has been a partial, belated, recognition of this failure.  Tim Flannery was quoted in the Melbourne Age of February 20  2010 (page 11) as blaming scientists for a rise in climate scepticism, saying they had not clearly explained the science to a confused Australian public.  He also said that the only way to solve that is to listen to the Australian people’s questions and talk to them about it, and the scientists have been rather poor at doing that.

James Norman, of the Australian Conservation Foundation, said the strategy of ignoring climate change sceptics had not worked as it had been taken as confirmation of their claims (The Age, February 21 2010, page 6).

All of this has been compounded by Climategate and Glaciargate.

In what has become known as Climategate, emails dating back over decade at the Climate Research Unit of the University of East Anglia (UK) were hacked into and made public in November 2009.  They are claimed by some denialists to be proof of a climate swindle and a conspiracy amongst climate scientists.  At worst, the scientists clearly are angry at climate change naysayers and have reacted in a human way.  They have also been over-protective of their data and need to be more transparent.

More recently, a claim made in an IPCC report about the melt rate of glaciers in the Himalayas has been shown to be false – it claimed a much faster rate than can be supported by evidence.  This was a sloppy mistake and not the only one.  But this does not affect the basic science underpinning the vast majority of conclusions.  The Australian newspaper ran a page 1 article on January 18 2010 about Glaciergate – far more prominence than they have devoted to the more important and uncontentious findings of the IPCC.  The Australian had several prominent follow up articles on this error on subsequent days.    

Evidence of rising doubts

There is ample evidence from around the world that the public conviction has waned.  Here I present some data from Australia.

The perceived likelihood of particular events happening in the next year has been measured by foreseechange since 2005 (the wisdom of the masses).  Clear signs of global warming in 2010 was rated as a 54.4% chance in late 2009 (Chart 1).  This figure is considerably lower than in previous years (Chart 2).

 Chart 1

 Chart 2

The slump in November 2009 (which preceded the Copenhagen failure) is somewhat at odds with the actual temperatures in 2009.  The Bureau of Meteorology reports that Australia’s annual mean temperature for 2009 was 0.9 degrees above the 1961-90 average, making it the second warmest year since high-quality records began in 1910.  High temperatures were especially notable in the southeast during the second half of the year, with Australia; Victoria; South Australia; and New South Wales all recording their warmest July to December period on record.  There were record heat waves in Victoria in January and February 2009 and in South Australia in November.

Why the denial argument is false

The claim that the temperature has not increased since 1998 is erroneous.  In the first place, the year 1998 was particularly hot and is a misleading choice of base year.  It is rather like observing in the 1960’s that the tallest building, the Empire State Building had been the world’s tallest building since 1931 and, therefore, the average height of buildings was not increasing or was even going down.  In the second place, random variations in temperature from year to year (the noise) are much greater than the expected rise in temperature over a decade (the signal) of about 0.1 to 0.2 degrees Celsius.  The picture becomes more clear with averaging, which reduces the noise – the decade 2000 to 2009 was hotter than the decade 1990 to 1999 by a statistically significant margin.

Even if the temperature had not increased over 10 years, it would still be erroneous to conclude that because the amount of carbon dioxide in the atmosphere had increased, carbon dioxide concentrations do not affect temperature.  That is because there are many factors which affect temperature.  One is methane, a much more powerful greenhouse gas than carbon dioxide, the concentration of which did not rise significantly during the period 2000 to 2009 after decades of increase.  Another is sulphur dioxide, which is emitted by coal fired power stations, but increasing concentrations of this gas decreases the temperature.  So if concentrations of sulphur dioxide have been increasing, perhaps due to the rapid construction of coal fired power stations in China and India, temperatures in some places would be falling.

Thus, we must take all factors (and there are several others) into account before we can accurately quantify the impact of increased carbon dioxide on temperature.  In fact, this can be done experimentally (by controlling other components) and was done over a century ago.  There is no doubt that higher carbon dioxide concentrations will increase the temperature by a known amount, all other things being equal

The multi factor influences on temperature are analogous to the situation of our discretionary household income.  Our discretionary income is increased by salary increases but reduced by increases in income tax rates.  If we have a mortgage, our discretionary income can rise or fall as interest rates go down and up.  It would be possible to have a period of several years when our salary was increasing but rising taxes and interest rates kept our discretionary income static or even reduced it.  But it would be erroneous to argue that increases in our salary do not tend to lift our discretionary income.


Climate scientists have failed to mount convincing arguments to demolish simplistic, erroneous, but powerful claims by denialists.  Indeed, it is open to question whether they have even tried to do so.  These failures by climate scientists have resulted in the wasting of many years during which action should have been taken.

The ultimate cost of this procrastination could be immense.  This would be the second climate change catastrophe.

Charlie Nelson
9 March 2010