When I was growing up in Tucson, it was a much cooler place. Most summer days hit 102 or 103. Now it will hit 110+. Why?
When I was young, there were entire 1 sq mile parcels of empty land inside the city. In a number of places, there would be a subdivision occupying 1/4 of a 1 sq mile parcel of land, with 3/4 empty. 2-story buildings were rare, and building above 3 stories almost nonexistent (except in the immediate downtown).
Now, it has filled in. The streets are 3 lanes in each direction instead of one. There is very little empty land. Subdivisions are now built with houses touching each other instead of with large backyards.
Yet somehow it is CO2 making Tucson hotter, and not the huge population increase and all the buildings...
I now live out in Vail. We are about 1000 feet higher (and about 20 miles from where I grew up). Our typical summer highs are 99-101. A thousand feet higher, and 10 deg cooler - does that sound like a normal temperature gradient?
Tucson’s population around 1970 was around 262,000...with massive growth in the 1960s (it was 45,000 in 1950).
If you could measure all asphalt and concrete in the city and come to ratio mix....it would explain the heat-sink concept completely. You can drive to the outer limits of Tucson and find it five to eight degrees cooler than the mid-city area. All due to infrastructure.
In Germany, we have a third-option besides concrete and asphalt....with this garden-brick arrangement. If you pull into a parking lot which has this as the base....even on a day when the temperature gets up around 90 degrees....the heated-up feeling that you’d have on normal asphalt isn’t there, so instead of 94-96 degrees in the middle of a parking lot....it’s just 90 degrees like it should be. Toss in a few trees (some shade) and you’d almost think that 90 degrees is bearable.