The oil industry stole the summer days this county used to work through.
The air in the shop gets thick enough by two in the afternoon in late June that the sweat sits on the skin without doing what sweat is supposed to do — the evaporation that pulls heat off the body, the physics that lets a working man keep going. I stand in front of the big fan before I can pick up the wrench again, and the fan moves hot air around, and the humidity keeps the sweat from doing its job. The body’s primary cooling mechanism does not work when the air already holds as much moisture as it can hold.
A study published Monday in Nature Climate Change puts a number on what the body already knows. The researchers, led by Rebecca Emerton, moved past the standard metric — air temperature alone — and used the Universal Thermal Climate Index. That index combines temperature, humidity, wind speed, and solar radiation into a single measure of what the environment actually does to a human body trying to stay cool. Temperature alone does not tell you whether a day will kill you. The body’s real thermal load is what matters, and that load is climbing across the inhabited world.
The study’s most important finding is about humidity. When the air is hot and dry, sweat evaporates and the body cools itself. When the air is hot and wet, sweat soaks through your shirt by nine in the morning and is still sitting on your skin at noon. The body’s only cooling mechanism shuts down. The researchers documented that regions previously untouched by this kind of stress are beginning to experience it. Humid heat waves are more fatal than dry ones — the difference between a heat wave you survive and the kind you don’t — and the places now gaining a month or more of those days include Mexico, Kenya, Italy, and any county where the air turns close and the nights stop cooling.
Every farmer and every mechanic and every person who has worked a Wisconsin afternoon in July already knows this in their bones. The notebook on the bench records what the study measures, in a different language. The number of nights per summer when the house will not cool below 78 by bedtime has climbed every year I have kept track. The number of afternoons when the fan does nothing useful has climbed too. Over the years the ice-out date on Lake Petenwell has moved earlier — the kind of phenology Aldo Leopold tracked in the sand counties south of here. The same warming that pushes ice-out earlier in March extends dangerous heat deeper into September and October. These are not observations that require a climate model. They are the kind of thing a man notices when he pays attention to what the air tells him.
The study attributes the increase directly to the burning of fossil fuels — coal, oil, and gas. The researchers said it plainly. The warming is human. The driver is combustion. I buy diesel at the cooperative fuel station on Highway 13. I burn LP gas to heat the shop in winter and I burn it again for the dehumidifier that keeps the parts room from rusting. The grid electricity that runs the shop when the solar panels aren’t producing comes from the same economy. The Silverado in my driveway gets fourteen miles to the gallon. I am the fossil fuel economy.
Wendell Berry wrote in The Unsettling of America that the extractive mind treats land and animals and people as expendable inputs. This heat study is the extractive mind’s latest invoice. Two more months per year when the air itself becomes hostile to the people who have to work in it — the roofers, the farmhands, the road crews, the people hanging drywall in a house with no air conditioning, the woman stocking shelves at the Dollar General loading dock at six in the morning before the heat sets in. These are not people who can work from home. The heat falls hardest on the people already carrying the most. The window units running in every trailer park on County Highway G from May through September are the proof.
Aldo Leopold wrote that the first rule of intelligent tinkering is to save all the parts. The parts being saved in this case are the quarterly dividends and the shareholder returns. The parts being lost are the cool afternoons, the safe work days, the nights that used to let a body recover from the heat of the day before.
I have two children. They are eight and five. By the time they are my age, the heat stress days will have climbed further. The physics guarantees it. The companies that made the sale will not be the ones working a Wisconsin afternoon in July when the air runs out of room to hold the sweat.