To a person with a hammer, everything proverbially looks like a nail. So the New York Times warns us of “underground climate change” which at least is underground but which has nothing to do with climate change despite the name. The ground under Chicago, apparently, is warming because of human activity. No, not the dreaded global warming. The fact that buildings are heated and some of the heat escapes into the ground underneath. The Times of course tries to blame fossil fuels, but only monomania can explain their failure to realize that if cities are local hotspots, it doesn’t prove atmospheric CO2 caused thermometers to read hotter there, but it does prove once again that urban areas are not good places to measure global climate.

The story starts “Underneath downtown Chicago’s soaring Art Deco towers, its multilevel roadways and its busy subway and rail lines, the land is sinking, and not only for the reasons you might expect.” Moreover:

“It isn’t just Chicago. In big cities worldwide, humans’ burning of fossil fuels is raising the mercury at the surface. But heat is also pouring out of basements, parking garages, train tunnels, pipes, sewers and electrical cables and into the surrounding earth, a phenomenon that scientists have taken to calling ‘underground climate change.’”

And apparently the expansion and contraction of the ground is causing some cities to sink. Which makes us wonder whether some cities supposedly threatened by “man-made” sea-level rise might not have similar problems. But never mind, for now, because the key point here is that if something is raising the mercury in thermometers sitting on top of these giant local heat sources it’s not “humans’ burning of fossil fuels” or at least not in the sense they mean.

Much of this heat, of course, does come from natural gas or oil and in places like China coal. But it’s not warming the cities indirectly and from above via rising atmospheric CO2. It’s distorting the temperature readings directly from within via rising heat from subway steam. Which is not a global crisis.

As the story says:

“To assess underground climate change in Chicago, Dr. Rotta Loria, an assistant professor of civil and environmental engineering at Northwestern, has installed more than 150 temperature sensors above and below the surface of the Loop. He combined three years of readings from these sensors with a detailed computer model of the district’s basements, tunnels and other structures to simulate how the ground at different depths has warmed between 1951 and now, and how it will warm from now through 2051. Near some heat sources, the ground beneath Chicagoans’ feet has warmed by 27 degrees Fahrenheit over the past seven decades, he found. This has caused the earthen layers to expand or contract by as much as half an inch under some buildings.”

Got that? Near some local heat sources temperature has risen 27°F or 15°C over seven decades and it has nothing to do with CO2 or “global warming”. Except, again, the bit where you imagine a non-existent trend. Because if your sensors are in places where this heat is radiating upward, and especially if they’re in places that were rural or suburban in 1980 and are now urban, you’ve got a measurement error creeping in relentlessly and need to fix it.

Specifically, if cities worldwide are hotspots, and you want to know what global temperature is doing, you have to stop measuring it in hotspots even if it’s more convenient. And in the name of scientific integrity, stop doing it on airport runways. Really. Right now. Talk about a thumb on the scale.

Of course if you take seriously the idea that cities are warmer than the surrounding countryside for reasons that are local not global, it means there isn’t a crisis that will kill us all if we don’t renounce prosperity. Which would actually be good. Right guys? Right?

Nooooo. Must be doomed. And so:

“Dr. Rotta Loria’s calculations assume that air temperatures in Chicago remain at their average recent levels all the way through 2051 – that is, his estimates don’t incorporate climate scientists’ projections for future global warming. Nor do they account for the fact that, as we continue warming the planet, large buildings will most likely use more air-conditioning and pump even more waste heat into the ground.”

Put down that hammer. Please. A thermometer is not a nail.