Ozdemir, H., Unal, A., Kindap, T., Turuncoglu, U.U., Durmusoglu, Z.O., Khan, M., Tayanc, M. and Karaca, M. 2012. Quantification of the urban heat island under a changing climate over the Anatolian Peninsula. Theoretical and Applied Climatology 108: 31-38.
The Anatolian Peninsula comprises the Asian part of Turkey, lying in the Eastern Mediterranean at the confluence of Europe, Asia and Africa, the urban population of which grew from about 25% of its total in 1945 to approximately 45% in 1980 and then, more rapidly, to close to 80% in 2007.
What was done
Focusing on cities having over half a million inhabitants representative of urban conditions and much smaller towns representative of rural conditions - all of which also possessed continuous high-quality temperature data from 1965 to 2006 - the authors studied the four-decade trends in daily minimum air temperature at each location.
What was learned
Very simply, the eight researchers report that "statistical analysis of daily minimum temperatures for the period between 1965 and 2006 suggest that there is no statistically significant increase in rural areas." However, they say that all of the urban sites, as well as the differences between urban and rural pairs, show significant increases in temperature, indicative of a strong urban heat island (UHI) effect over the region. In fact, as they describe it, the average "urban station is over 4°C warmer than rural."
What it means
Whereas it is claimed by many climate alarmists that adequate adjustments are made for urban heat island effects when compiling data from all around the world to deduce a global mean near-surface air temperature representative of non-urban conditions, we wonder to what extent the world's many urban sites have had their warming reduced to zero over various time intervals (especially more recent ones), as would appear to be needed on the Anatolian Peninsula. If this has not been done there, as well as at other locations where it may have been warranted, it could well be that historical greenhouse gas-induced global warming has not been nearly as large as it has been portrayed to be.