Climate change debate no place for silliness

Climate change debate no place for silliness

02 Feb 2010

harry-clarke Professor Harry Clarke

La Trobe University’s Professor John Carroll in The Age (January 27, 2010, page 13) makes irresponsible remarks on the issue of climate change.  His article misrepresents climate change science and the policy required to respond to climate change.

Carroll argues that the global warming debate has been captured by the “prophets of doom” raising the same risk of irrelevancy as the “Limits to Growth” discussions of the 1970s.  Has Carroll read the evidence on catastrophic risks associated with climate change or are these observations just a cheap shot? The famous MIT economist Martin Weitzman has examined the prospects for catastrophic climate change.  His estimates are based on 22 simulation models provided by the IPCC and show that if emission control policies are only gradually ramped up remedies that, in two centuries, the probability distributions of temperature outcomes have ‘fat’- tails. In simple terms:

  • With probability 0.05 the increase in mean global surface temperatures will be greater than 10oC.
  • With probability 0.01 the increase in mean global surface temperatures will be greater than 20oC.

Such temperatures have not existed on earth for hundreds of millions of years and the rate of such increases has possibly not been experienced for billions of years.  With a 1-5% probability (not a negligible range of probabilities) there is the prospect of a worldwide catastrophe.  Is it then wise to rule out the possibility of this risk when climate change policy is discussed?  Is it sufficient to preach about the dangers of ‘alarmism’? What about the prospect that there may be a catastrophic risk that should be addressed by policy?

Carroll’s second class of cheap shots concerns his critique of the use of ‘computer generated mathematical models’.  This is inaccurate language since it isn’t the models which are computer-generated – these are designed by climate scientists – but model outputs such as forecasts.  But more significantly, what is the alternative to using models to make climate forecasts? Is the best alternative merely to wave your arms and express scepticism? What alternative methodology might one employ to assess the impact of human and natural-sourced climate drivers than by using quantitative modelling?

Carroll finishes his analysis of models by making the unproven claim that these models are “next to useless for long-term prophecy” because they don’t capture every aspect of reality and because the future might be different from the present.  This is naïveté and displays a misunderstanding of the methodology of modelling. A road map doesn’t need to literally represent reality to be useful. Given that forecasts are needed and that models cannot be constructed capturing every aspect of reality one could reasonably ask how one might otherwise proceed by using simplifications of reality? Arm-waving again will not do the trick.

If Carroll is merely saying that one should be sceptical in the sense of being prepared to alter one’s position on the basis of new facts then what he is saying is blindingly obvious? Everyone should maintain an open mind in that obvious sense.

On the facts concerning climate change Carroll distorts reality. He claims that “global temperatures have been stable for the past decade” which is grossly misleading since as various meteorological authorities – including our own Bureau of Meteorology – have pointed out that the last decade was the hottest in recorded history.  What Carroll is omitting to say is that that 1998 was a year of record temperatures and this record was not repeated subsequently. How often must these myths in interpreting climatic data be repeated?  They have been refuted on so many occasions that one wonders whether commentators like Carroll read much at all about climate change issues. How much intellectual effort does it take to understand that you cannot evaluate the trend behaviour of a time series by picking out an extreme pair of observations? Averaged over the whole decade temperatures to 2009 however rose in a fashion consistent with climate change. 

The inconsequential, non-events at East Anglia and the single error on glaciers in 3000 pages of IPPC text – an error not repeated in the Executive Summary or in the IPPC’s AR1 (“Physical Science Basis”) report – are used to attempt to discredit the thousands of reputable scientists involved in climate change research – including our own CSIRO – who have a very definite view on the consequences of accumulating greenhouse gas emissions on climate.  It is a distortion to dismiss the mainstream science of climate change because of the questionable behaviour of a few individuals or an isolated error of fact.

The ETS is dismissed as “very bad policy” and “a tax on carbon under another name”.  This isn’t argued by Carroll but asserted.  But what is wrong with the policy and what is wrong with taxing something that is harmful and currently unpriced? By allowing emissions permits to be traded they go into their highest valued uses so that markets provide the cheapest way of controlling carbon emissions.  The exemptions given to groups such as electricity generators (now $7.2b) are a disgraceful waste on money since these firms provide non-internationally traded good (electricity) whose demands are relatively price unresponsive.  The surprising thing is that it was opponents of the ETS who supported this inept policy move on the grounds that we would have “brownouts” around the country without it.  These massive payouts were funded by reduced concessions to taxpayers which earlier would have made the ETS effectively revenue-neutral with consumers paying higher prices for carbon-based electricity but being compensated for this in terms of income so they were no worse off.

Carroll’s claim is that the ETS isn’t worth considering because it doesn’t include agriculture.  It would have been better to include agriculture in an ETS to capture methane as well as the carbon emissions Carroll mentions. But surely if the objective is to control emissions it is better to capture some emissions than none.  Inconsistently with his agricultural views Carroll argues that only “major emitters” should be targeted by an ETS. But they are – it is only about 1,000 emitters who are covered by the ETS legislation.  It is important to be informed about the ETS before you criticise it.

I agree with one and only one aspect of Professor Carroll’s argument. The sceptics are indeed winning the political debate on climate change. Part of the reason for this is the sort of poorly-informed debate that people such as Professor Carroll are actively promoting.  It is not enough to present oneself as an ambivalent sceptic on the modern science of climate change without attempting to make oneself informed of its content and making a modest effort to understand the literature.  The costs of being wrong are too great.




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