Urban heat island features of southeast Australian towns

This review of the above paper is from  www.co2science.org  see links page.
The 13 pages can be read or downloaded below, each page gif file is from 90 to 135 Kb.
Update 27, June.   216KB pdf            Link to Urban heat island features of southeast Australian towns

Torok, S.J., Morris, C.J.G., Skinner, C. and Plummer, N.  2001.  Urban  heat island features of southeast Australian towns.  Australian Meteorological Magazine 50: 1-13.

What was done
The authors studied the characteristics of urban heat islands in several cities in Australia with populations ranging from approximately 1,000 to 3,000,000  people.

What was learned
The maximum urban-rural temperature differences of the Australian cities were found to scale linearly with the logarithms of their populations. The authors noted that the same was true for cities in Europe and North America, but that the heat islands of Australian cities were generally less than those of similar size European cities (which were less than similar size North American cities) and that they increased at a slower rate with population growth than did European cities (which increased slower than did cities in North America).  The regression lines of all three continents essentially converged in the vicinity of a population of 1,000 people, however, where the mean urban-rural temperature difference was approximately 2.2 0.2 C.

What it means
The results of this study suggest that very small towns, with populations measured in mere hundreds of inhabitants, likely have urban heat islands that are on the order of the entire amount of global warming that is believed to have occurred since the end of the Little Ice Age.  With such small aggregations of people having such a dramatic impact on air temperature, it is ludicrous to believe that on top of the natural warming experienced by the earth in recovering from the Little Ice Age we can confidently
discern an even more subtle increase in background temperature caused by concomitant increases in greenhouse gas concentrations.  Changes in population, which have generally been positive nearly everywhere in the world over this period, could easily explain whatever tiny bit of warming is left after the natural component of warming (which must be substantial, relatively speaking) is subtracted from the total amount of warming recorded by the totality of earth's thermometers over the past century or so.

Additional comment by Warwick Hughes

Those few of us greenhouse sceptics who understand global temperature records will be gratified that  95 years after the formation of the Australian Bureau of Meteorology (BoM) they have acknowledged the existence of the urban heat island (UHI) in very small towns of ~1000 population.  Possibly prompted by the PhD research carried out by Christopher J.G. Morris.
We live in hope that the BoM might discover and publish the extent that UHI bias has contaminated century long temperature trends in Australia.

This is a good point at which to remember that the USA climate research team that put together the GHCN set their rural cut-off at 10,000.  This can now be seen for what it is, a ridiculously high figure that has ensured that much UHI bias remains in the "Rural" series of the GHCN.

To read the full paper work your way down these links use your Back button between pages.

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Posted 12, June, 2002

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