Sunday, 7 May 2017

Urban Heat Island could account for up to 80% of the recorded warming."

Paper by Quereda et al. (2016) (link)


Abstract (link)

This investigation completes the line of work on the thermal evolution of the Mediterranean region (Murcia and Valencia regions) in the National Plan on Climate Change. The study was undertaken to analyse the active regional thermal series over the 1950–1999 period, rigorously treated by the SNHT (Standard Normal Homogeneity Test) method.

In this context, fifteen years later, it was considered judicious to verify the validity of the trends and conclusions that the regional climate offered at the end of the 20th century. The objectives of this study are twofold: the verification of the Significant Climate Warming in the Spanish Mediterranean concluded in the National Plan on Climate Change (1950-1999) and the evaluation of the importance that the Urban Heat Island (UHI) has on the warming process.

Within the context of the thermal evolution of the region over the 1950–2013 period, this verification has been supported by an experimental research plan aimed at analysing the thermal processes inherent to the urbanisation effect.

Although the effect is undeniable, its importance is a matter of controversy. The results obtained have shown both the nature of the phenomenon and its significant magnitude. This magnitude could account for between 70 and 80% of the recorded warming trend in Western Mediterranean cities.

Therefore, failure to take this process into account might seriously bias any analysis of regional thermal evolution, the main aim of this study and an aim that equally affects the hypothesis of global climate

Idso's CO2 Science address this report: (link)

Quereda et al. (2016) begin their work by stating that although "it may be accepted that urban heating is of local importance, there is no evidence that it alters the global temperature trend," citing the IPCC (2001). 
However, they backtrack significantly in this regard throughout their analysis of the subject by stating that "on comparing the temperature of urban areas and rural areas, various researchers have concluded that the urban effect could account for between 40% and 80% of the observed thermal trend in the last few decades," citing the studies of Ren et al. (2007), Yan et al. (2010), and McKitrick and Michaels (2007), who concluded that half of the warming trend observed between 1980 and 2002 could have arisen from changes in land use. 
In studying the subject in even more detail over the 1950-2013 period, it was further found that this phenomenon could "account for between 70 and 80% of the recorded warming trend in Western Mediterranean cities." And in light of this discovery, Quereda et al. pose the important question: "are urban areas contributing to the observed warming trend on which climate change is based?" to which they respond by stating that "the answer to be drawn from our analysis is fully affirmative." And so they conclude by stating that "in these Western Mediterranean cities, 

"the Urban Heat Island could account for up to 80% of the recorded warming."