Sunday, February 10, 2013

A climate of scepticism - Part III

In this final part of my climate paper, I talk about extreme events and other scare stories, and about how some scepticism is the result of the excessive zeal of climate change proponents.

Disasters that have nothing to do with a changing climate are ascribed to “climate change” as a means of raising awareness about the supposed threats. Nothing illustrates this aspect of the debate better than the ongoing accent on “extreme events.” A violent storm, such as the recent Sandy that struck New York, is immediately seized upon as evidence of “climate change.”

Weather is ever variable. The vigour of every natural phenomenon has a wide range. Many phenomena, for example rainfall, are best described by a distribution which is very strongly skewed.  Such distributions are quite counterintuitive when it comes to trying to define what constitutes “extreme”.

The problem is how to decide the width of the ‘normal’ range, a decision essential for describing an event as abnormal or ‘extreme’, that is, lying outside the normal range.   A lot of data is necessary to define ‘normal’, which implies that data must be collected over a long period. The long period may exceed a human lifetime.  If so, then few living individuals can have experienced the truly “extreme” events – and an event much less than extreme may be seized upon as an example of an extreme event when in fact it is no such thing.

In the case of storm Sandy, there has been an assessment of the intensity of all hurricanes and “post-tropical storms” (of which Sandy was one) that made landfall on the continental United States between 1900 and 2012. The data are shown in Figure 8[i].

A person born in 1900 would probably have experienced their most extreme event in 1936.  However, that person might have lived to the age of 106, and would have seen two stronger storms. That might have convinced him/her that the world was getting worse.  He/she would have been wrong, of course – the random nature of extreme events would have fooled them. 
Figure 8.  Power dissipation index of storms which made landfall on the US, 1900-2012
This illustrates quite nicely how long one must wait before one can determine even the 100-year event – and how just because there has been such an event, another nearly as bad can turn up in less than 100 years after that! The statistics of extreme events are counterintuitive, and very long baselines are needed before it is possible to decide if something is extreme or not.

There has been extensive concern about extreme events, partly because almost every day somewhere on the globe there will be an event that might be describable as ‘extreme’. The IPCC has issued a special report on the subject[ii]. It can probably best be described as ‘delphic’ – a series of very cautious pronouncements that can be interpreted in different ways, depending on your viewpoint. Probably the best measure of the extent to which extreme events should be viewed as likely to be caused by climate change comes from a study of deaths caused by severe weather[iii].  The results are shown in Figure 9.

It is clear that the absolute number killed each year has dropped since the 1920’s.  In relative terms, the drop has been even more dramatic, from a peak of 241 per million to 5 per million.  At this low rate, extreme weather no longer presents the same risks as faced previous generations.

Figure 9. Deaths and death rates per million people from extreme weather events
 The reasons for this steep decline are several.  One is vastly better weather prediction, so that there is now adequate warning about possible extreme weather conditions.  Secondly, there is much better communication of impending severe weather. Finally, with improved knowledge of severe conditions, mankind has learned to design structures that protect us from the hazards. If ‘climate change’ is having any effect, it is invisibly by this measure.

The final scare story that needs to be laid to rest is that of species extinction as a result of climate change. The popular press reports this regularly. “’Climate change now represents at least as great a threat to the number of species surviving on Earth as habitat-destruction and modification,’ said Chris Thomas, a conservation biologist at the University of Leeds in the United Kingdom. - - the predicted range of climate change by 2050 will place 15 to 35 percent of the 1,103 species studied at risk of extinction. The numbers are expected to hold up when extrapolated globally, potentially dooming more than a million species. ”[iv] 

However, science prefers predictions that are testable. A recent serious study concluded that “Surprisingly, [there is no] straightforward relationship between local extinction and limited tolerances to high temperature.” [v] Indeed, this follows from common sense.  Figure 10 shows the average monthly conditions for Cape Town. The boxes show the average daily maxima and minima, the lines show the highest and lowest temperatures ever recorded, and the lower and upper horizontal lines reflect the annual average temperature in 1900 and 2000 respectively. 
Figure 10. Monthly temperatures in Cape Town, and annual averages in 1900 and 2000
It is reasonable to ask how the relatively small average temperature change can be detected by organisms that every year are likely to be exposed to changes some 50 times larger, to which they seem perfectly adapted.

The final reason for ongoing scepticism is the behaviour of some of the proponents of the climate change thesis.  It starts with the Intergovernmental Panel on Climate Change.  It has become a political body rather than a technical body.  The best illustration of this is the publication of the Panel’s reports.  It is preceded by the publication of a summary for policy makers. This summary often differs in material respects from the findings of the main report, and invariably puts a politically correct slant on what is supposed to be a dispassionate review of the scientific literature[vi]

The IPCC’s work is not aided by the fact that much of the work reported is not scientific, but reproduced from activist literature.  The Canadian journalist Donna Laframboise has documented this problem in detail[vii].

For example, she tracks how a relatively unknown professor of epidemiology, Anthony McMichael, who had written a polemic in 1991, became a lead author of the chapter on malaria and the health effects of climate change, even though he had no professional publications about malaria and even though some of his conclusions were rejected by members of the Panel who were world experts on the subject. 

Sections of McMichael’s book appeared almost verbatim in the IPCC’s Assessment Report in 1995. This led directly to the thesis that global warming will increase the spread of malaria. There is no evidence that this is likely, because malaria has been known in cold climates for centuries. Moreover, the spread of malaria is known to be almost entirely a function of social conditions and public health.

The fight against malaria is not helped by those who claim that climate change is part of the problem. If they had their way, the accent would be on addressing climate change rather than fighting malaria. This illustrates a danger of accepting a possibly flawed thesis too uncritically – resources may be diverted from essential activities affecting the lives of millions in the hope that there will be a positive impact on putative risks that might possibly affect billions.  Before taking such a decision, one needs to be very certain indeed that the putative risks can be avoided by the diversion of resources.

Another reason for scepticism is that the debate about climate change has revealed some major imperfections in the scientists themselves. Some players on the human-induced climate-change playing field have shown themselves to be only too human in the defence of the indefensible. For example, two scientists did what scientists are supposed to do – they peer-reviewed the work of some 200 other scientists[viii].  They reported that:

Across the world, many records reveal that the 20th century is probably not the warmest nor a uniquely extreme climatic period of the last millennium.

This was totally contrary to the thesis that today’s warming was exceptional. Accordingly the believers in human-induced change forced the editor of the journal that had published the review to resign, and went out of their way to try to destroy the reputations of the two authors.  All this (and more) was revealed when a series of emails found its way into the public domain from the Climate Research Unit at the University of East Anglia[ix].

The world is slightly warmer than a century ago.  The carbon dioxide levels of the atmosphere are increasing.  Plants are doing better than before because of the higher carbon dioxide[x]. The sea is rising in a barely detectable way. Climatic disasters are no worse than previously. The animal kingdom is being squeezed by the growth of a single species, us, but that has nothing to do with global warming.

And that is why there is a climate of scepticism.

[ii] IPCC, 2012: Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation. A Special Report of Working Groups I and II of the Intergovernmental Panel on Climate Change [Field, C.B. et al (eds.)]. Cambridge University Press, Cambridge
[iii] Goklany, I.M. Wealth and Safety: The Amazing Decline in Deaths from Extreme Weather in an Era of Global Warming, 1900–2010. Reason Foundation, Washington DC and Los Angeles, CA, 2011
[v] Cahill, A.E, Aiello-Lammens, M.E., Fisher-Reid, M.C., Hua, X., Karanewsky, C.J., Ryu, H.Y., Sbeglia, G.C, Spagnolo, F., Waldron, J.B., Warsi, O. and Wiens, J.J. How does climate change cause extinction? Proc. Royal Soc. B 2012 doi: 10.1098/rspb.2012.1890
[vii] Laframboise, Donna The Delinquent Teenager who was mistaken for the world's top climate expert. Ivy Avenue Press, Toronto 2011. ISBN: 978-1-894984-05-8
[viii] Soon, W. and Baliunas, S. Proxy climatic and environmental changes of the past 1000 years. Climate Research Vol. 23, pp89–110, 2003

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