The urban heat island effect drives climate change

My good friend William Teach of The Pirate’s Cove snarked this morning that it was “Your Fault: ‘Climate Change’ Made Current Raleigh Heat Wave More Likely,” which amused me greatly. I know, I know, it’s just shocking, shocking! that it got hot in a major urban area in the South, in the summer, but Mr Teach mocked WRAL telling people how horrible the heat was, and that it was all the fault of global warming climate change.

As it happens, I have my own weather station, and I’m OCD enough to keep an eye on it. And what I’ve noticed is that while yes, it got into the nineties at the farm, it was still a few degrees less than the forecasts.

It was 69.4º F at 7:00 this morning, lower than the forecast of 72º for that time.

Of course, the forecasts are made by experts living in the cities, and the weather reports are being made by broadcasters in the city, and the Lexington temperatures, which are what get reported, are taken at the concreted-over airport.

What we don’t have out here in the sticks is the urban heat island effect, we don’t have as much concrete or asphalt, and we do have more grass and trees and other plants.

Look how green the soybean is after Wednesday evening’s 0.21″ of rain! The river is to the left of that tree line. Click to enlarge.

How much of global warming climate change comes not from actual change but same site temperature monitors being more and more surrounded by concrete and asphalt? The Lexington temperature has been ‘officially’ recorded at Bluegrass Field for as many decades as I’ve known — and we first moved to Kentucky in 1962 — and the airport has been expanding continually all along. It’s still west of the city off of Versailles — pronounced ‘ver-sales‘ — Road, outside of the urbanized area itself, in the midst of some of the horse farms and across Versailles Road from the Keeneland race track, but the city itself and the urban heat island it creates have been expanding, despite the government-mandated restrictions protecting the agricultural areas, from 62,810 people in the 1960 census, to 204,165 in 1980, to 322,570 in 2020, and an estimated 329,437 in 2024. All of those extra people needed someplace to live, needed the extra housing, and the extra businesses in which to work.

Lexington’s population is now 5.24 times what it was in 1960. In contrast, Mt Sterling, Kentucky, where I grew up, is only 41.0% more populous, 7,571 versus 5,370, than it was in 1960. The entire county, Montgomery, has grown faster, 2.14 times since 1960, 28,771 versus 13,461, with some suburb expansion into formerly rural areas, but people are still not crammed together the way they are in Lexington.^[1]Lexington comprises all of Fayette County, urban and rural.

All of that concrete and asphalt have an effect. Not only is it hotter in the cities, but concrete and asphalt retain that heat better than trees, grass, and soil. We can ditch every gasoline powered car and it will still be hotter in cities, and that will continue to skew temperature records.

I might not be quite the country boy John Denver was!