Every now and then we come across a new journal article that reminds us of the challenges that exist in finding an anthropogenic signal within the near-surface temperature record.
The latest study to cross our desks that gives us pause in this regard is from Levermore et al. (2018).*
The essence of their work included an examination of the urban heat island in Manchester, UK.
Using hourly temperature data from an urban and rural (~12 km away) UK Met Office site over the period 1996-2011, the five scientists calculated a statistically significant urban heat island influence of 0.021°C per year in the Manchester data, which trend is “approximately equal to the lower predictions of climate change.”
Levermore et al. also calculated the change in urban morphology between 2000 and 2009 based on changing aerial green space, determining that “the green area has reduced by up to 11% over the whole area shown, although it is only a 1.5% reduction within 200 m of the [urban] station.”
And it was this reduction in green space that was ascribed by the authors to be the main factor of urban heat island contamination in the Manchester temperature record.
Think about the above results. A 1.5 to 11% reduction in green space over a ten-year period was significant enough to raise temperatures in the Manchester record by an average of 0.42°C.
That spurious warming is about half the magnitude of warming that the world has seen globally since the end of the Little Ice Age over a century ago.
Clearly, correcting for urbanization effects is a knotty issue of climate science and, if not done correctly, will add spurious warming unrelated to natural or anthropogenic trends.
And that is one of the reasons that satellite-derived temperature data are considered to be superior to data collected at near-surface land-based locations.
*Levermore, G., Parkinson, J., Lee, K., Laycock, P. and Lindley, S. 2018. The increasing trend of the urban heat island intensity. Urban Climate 24: 360-368.
Read more at CO2 Science
Well, the satellite data must be adjusted because it doesn’t agree with the climate models.
(sarc.)
I don’t have the booklets in front of me right now, but back in the 1970’s, Radio Shack produced a series of booklets on semi-conductors and what they could be used for. One ‘experiment’ related to using a diode to measure temperature. Non-linear to heck and gone. Add bias, and it performed pretty well. The author had to drive his daughter across town (in Texas) each morning. He came up with (from memory) – a 3°F ‘hump’ in temperature as he passed through downtown. “Heat Island” is nothing new to engineers etc who actually go out and measure what is happening in the real world. Folks who come up with a theory and then play with it on a computer only to find that the results don’t match the real world — i’ve run out of polite words…..
https://www.therightinsight.org/Climate-Experiment
Thanks for the URL. One way to keep the youngsters occupied. “Digital” thermometers? How things change. It was vacuum tubes and analog tapes – seismic oil exploration – in the early 60’s. In ’67, digital equipment – in Papua. Today — I have a book on analog computers – fun to read about but I wouldn’t want to use one…..
There is no rural station 12 kilometers from Manchester. They are comparing two UHI corrupted stations.
UHI can be thought of as concentric domes of heat that extend from the center of city infrastructure, and increase in temperature as you approach the center. The effect goes well beyond the city limits, and raises temperatures for outlying areas. Every large city I have lived near has had temperature readings anywhere from 1-7 degrees higher than the actual rural stations.
The stupid that alarmists display is stunning.
City heat can trigger thunderstorms. Last year I was in town during a heavy downpour. I checked the radar.
There was no rain anywhere else, and the storm didn’t move. It started and finished over town.
I saw a Weather Channel feature about Atlanta. Meteorologists acknowledge that UHI triggers storms there.