Up to 44% of warming due to Urban Heat Island effect

UHI effects

A new paper in the Journal of Geophysical Research reveals that as much as 44% of recent warming may be due to the Urban Heat Island effect, caused by increasing urbanisation around temperature measuring stations. The study looked at over 460 individual stations in East China:

The trends of urban heat island (UHI) effects, determined using OMR [observation minus reanalysis] and UMR [urban minus regional] approaches, are generally consistent and indicate that rapid urbanization has a significant influence on surface warming over east China. Overall, UHI effects contribute 24.2% to regional average warming trends. The strongest effect of urbanization on annual mean surface air temperature trends occurs over the metropolis and large city stations, with corresponding contributions of about 44% and 35% to total warming, respectively. The UHI trends are 0.398°C and 0.26°C decade−1. (source – abstract only)

There is no reason to doubt the fact that similar contamination of the surface record would be occurring elsewhere. Which helps to explain why the surface record diverges so noticeably from the satellite record, and why the satellite record should always be favoured.

[Also little Jimmy Hansen doesn’t get to carry out his special kind of “data cleansing” either – Ed]

h/t Hockey Schtick


  1. Geoff Shaw via Facebook says:

    …ok, now the greens will want bulldozers put through every CBD… and while at it .. suburbia.

  2. Paul Taylor via Facebook says:

    Quick, lets have a concrete heat tax…..

  3. The degree to which urban development can influence the temperature record just goes to show how these people aren’t concerned with getting it right.

  4. If thats true,…then Just move the f#*king gauges and measuring station to get a true reading,…..Fu#K me,..talk about dumb.

  5. Ian Falconer says:

    Old soviet temperature records are ‘colder’ than actual temperatures as the soviet regime provided subsidised vodka and heating oil when the average daily temperature was below a certain amount. Apparently people used to ‘record’ the results so that they got more vodka and fuel. Data is great but how trusted is it is a question we must ask before making conclusions…

  6. What they don’t tell you is that they have reduced the number of monitoring points by 2/3rds and the ones kept are in many of these localised hot spots

  7. Baldrick says:

    A study by C.J.G. (Jon) Morris from the University of Melbourne was conducted in the small NSW town of Deniliquin with regards to Urban Heat Islands (UHI).

    “Deniliquin’s maximum and minimum temperatures were recorded at the Post Office from 1873 to 1971, before the station was relocated to the airport in 1984. The records from the Post Office indicate that in Deniliquin the annual average minimum temperature increased by 2.1 deg C until 1971. However when the monitoring station was moved out of the urban area, the last 20 years of record shows that the nighttime temperature is 0.6 deg C lower than the previous 98 year average. This indicates that the urban area of Deniliquin may be warmer than its surrounding rural regions. To test this, measurements were taken of the air temperature, wind speed and direction at seven locations along a transect on either side and through the center of the town. During February 1995, measurements in Deniliquin showed that on clear and calm nights, the town centre can be up to 4.2 deg C warmer than beyond the airport.”

  8. Sundance says:

    I wonder if they adjusted for SO2 that would cause the urban areas to be cooler than rural areas?

  9. Hi there!

    I made an estimate of Chinese temperatures:

    Surpricingly rid of warming, pretty much like Europe

    K.R. Frank

  10. Bo Darsenius says:

    Yes, of course. The fact that there are so many fastly growing cities in the Arctic explains why the Arctic is the part of the globe where the warming is most rapid…

  11. It would have been nice if you provided a link to or the title and author of the piece as I prefer to read the research for myself. There are too many politically motivated liars in the debate to take any blogger’s bare word on anything. [If you’d actually spent 10 seconds reading the post, you would have found the link to the abstract, which was there from the start – Ed]. I did not find the study but I did find this one suggesting that models that leave out human forcings cannot account for mid 20th century on warmings.


    Response of Earth’s surface temperature to radiative forcing over A.D. 1–2009
    Key Points

    Radiative forcing of ten agents created for A.D. 1–2009
    A simple energy balance model is tuned to a GCM
    Annual global temperatures are predicted A.D. 1–2009

    A. D. Friend

    Department of Geography, University of Cambridge, Cambridge, UK

    An energy balance model (EBM) of the annual global mean surface temperature is described and calibrated to the sensitivity and temporal dynamics of the Goddard Institute for Space Studies modelE global climate model (GCM). The effective radiative forcings of 10 agents are estimated over the past 2009 years and used as inputs to the model. Temperatures are relatively stable from around A.D. 300 until a “Medieval Climate Anomaly” starting around A.D. 1050. This is ended by a massive volcanic eruption in A.D. 1258, which initiates a multicentury era of low and relatively variable global mean temperatures, including a “Little Ice Age” A.D. 1588–1720. This era only ends at the beginning of the 20th century. The model estimate of forced centennial variability is smaller than the observed variability in reconstructions over the past two millennia. Also, the default parameterization results in less warming than observed over A.D. 1910–1944. Prediction uncertainty in the pre-industrial era is dominated by solar forcing, with the climate feedback factor and volcanic aerosols also playing important roles. In contrast, prediction uncertainty post–A.D. 1750 is much higher and dominated by uncertainties in direct and indirect aerosol and land use forcings. Improving estimates of these will greatly increase our ability to attribute observed temperature variability to contemporary forcings.

    • Kevin R. Lohse says:

      Dear John.
      “There are too many politically motivated liars in the debate to take any blogger’s bare word on anything.”
      You are quite correct. That is why sites such as Climate Audit, Bishop Hill, Climate etc, and this one exist at all.

  12. UHI may very well be affecting temperatures in areas that have undergone significant urbanisation over the past century.

    It doesn’t explain why rural stations, well removed from any cities, show a higher warming trend – particularly for the US, and especially when you only use the stations that have been ranked as “high quality” by the surfacestations.org project.

    Even the paper you’ve linked makes it clear that there is a significant warming trend – “Overall, UHI effects contribute 24.2% to regional average warming trends”

    This means that 75.8% of the regional average warming trends were not caused by UHI.

    The 44% figure, of course, only applies in the middle of large metropolitan areas. There’s certainly been phenomenal growth of those in China over the last few decades!

  13. All the extra urban warming doesn’t increase enough warmth in the whole atmosphere to boil one chicken egg. Because: when the 800km3 of air in the city become warmer = expand by 50km3. Those 50km3 extra expand into the stratosphere – intercept extra coldness – that extra coldness falls somewhere far away (usualy west over the sea) = there is colder, to balance. Please get all the scientific proofs on my website http://www.stefanmitich.com email me your adress for a coppy of my book. EXTRA HEAT IN THE PLANET’S ATMOSPHERE IS NOT ACUMULATIVE. Heat and coldness change places; even during an Ice Age. When any scientist finds now, or for in the past that some part of the planet was warmer – declaring that the whole planet is, or was warmer; is same as saying that: planet is warmer at lunch time than before sunrise…?! http://www.stefanmitich.com.au or email: undergroundpress@bigpond.com.au The laws of physics regulate the temperature, not shonky climatologis… they think they do.

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