A great little paragraph below explaining the issues with global temperature measurements, particularly when it comes to urban heat islands (UHIs). From Electroverse.
KEY QUOTE:
…why does the data show North America is cooling yet the planet overall is heating up? Well, one answer could be that weather station coverage is very good across the U.S. and Canada, whereas it’s very poor across much of the rest of the planet — and where coverage is thin (such as in Africa and Siberia, for example) NOAA simply guess the temperature. This filling in the gaps will be justified by saying that readings from the closest temperature stations have been used as proxy, but 1) this method will not give an accurate global temperature record as the closest temp station could be hundreds or even thousands of miles away, and 2) these stations will more often than not be located in cosmopolitan areas, and such areas have a proven Urban Heat Island bias and so will of course skew the overall picture. When natural vegetation is replaced with buildings, pavement, and spurious heat sources like air conditioning units and cars, the microclimate around a thermometer site changes. This expansion of inner-city readings to cover entire nations is probably, now, the sole driver of anthropogenic global warming…
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