The heavy black line at the top shows unofficially that in July 2023 the Earth’s reached its highest overall temperature ever recorded. Two-meter air temperatures are compiled through an array of measurements worldwide of temperatures 2 meters (about 6 1/2 feet) above the Earth’s surface. Graphic courtesy of NOAA and University of Maine Climate Change Institute

“It’s a wet cool,” Bonnie said on approximately Day Million of rain this summer.

This was a text she sent, actually, to her brother in Palm Springs, California, who had sent her his approximately millionth report of triple-digit heat, dryly observing how 113 degrees is a dry heat. Palm Springs is in the desert, about a hundred miles east of Los Angeles. The temperature there has topped 100 degrees every day since June 24. Since July 11, it has been 113 or hotter every day but one, according to AccuWeather. One day, it hit 120. Another, 119. And several 117s. The average daytime high there in July is 108.

The Southwest from California to the Gulf of Mexico has been baking in one of the worst extended heat waves in history. The meteorologists call the hot air that’s been parked over the whole area a heat dome. In the recent days, it’s been expanding.

Similar heat has enclosed southern Europe. Parts of Catania, Sicily, lost electricity and water for two days when it got so hot electric cables buried under roadways melted. In Greece, where serious drought- and heat-driven wildfires have affected tens of thousands of people, meteorologists named the first dome spawning record high temperatures Cerberus — the mythological dog guarding the entrance to hell. Then, after a brief period of slightly lower temperatures, they named the next dome of 90s and 100s Charon — the ferryman to hell.

Here in Maine, the problem has been moisture. It ain’t the heat, it’s the humidity, as we used to say in the olden days when whole summers passed without a 90-degree day. In June, the water pressure tank in our house was pouring so much liquid onto the basement floor we thought it had cracked. But it turned out to be condensation created by cold water from underground meeting persistently high dew points outside the tank, resulting in pools of tank sweat.

The air temperature seems to have been a bit above average, but not too far out of summer bounds. Ninety has appeared on our L.L.Bean weather station four or five times, which would have been a lot 50 Julys ago, but now seems to be expected. Still, even when it’s 85 or even 75, it’s been so sticky we shut the doors and windows to let the new heat pump work moisture out of the air. I honestly don’t know which I’d choose between sticky 90 and dry 113.

Down through the humid air has poured relentless rain. The brook that runs under our driveway is usually dry by mid-July. It’s full and roaring as I write. Walking the mile-long track at the Unity park, I keep picking my way across puddles. Western Maine caught the edges of the severe storms that inundated Vermont in the past few weeks.

Meanwhile, back in southern California, wildfires have burned thousands of acres and are roaring on. There’s not a lot to burn around Palm Springs, except buildings, luckily. So far. Heavy wildfires have been roaring in Siberia and Portugal again this year. In Greece, they’ve destroyed homes, cars and olive groves, and threatened oil refineries. In western Canada and Quebec, more than 25 million acres have burned so far this summer, sending up so much smoke it fouls the air in Maine.

The rain, the humidity, the droughts, the wildfires — this is all happening because the Earth is heating up.

The Gulf of Maine Research Institute registered the highest average monthly sea surface temperatures in the Gulf of Maine for March and April. The record highs backed off in May. But oceanographers worldwide have observed unprecedented huge spikes in sea surface temperatures. Near Key Largo, Florida, water temperature unofficially registered 101 degrees. If verified, it will be the hottest water temperature ever recorded on Earth.

In the first week of July, the average temperature over the whole world hit the highest ever for a single day.

Phoenix has had consecutive weeks of daily highs hotter than 110. On July 16, China had its highest recorded temperature ever — 126 degrees — in Sanbao, Xinjiang, in the arid western part of the country. The same day, a heat index of 152 degrees was recorded at Persian Gulf International Airport in Iran.

The human body cannot survive 152-degree heat. Serious stress on the body begins at around 90 degrees. At about 95 degrees, certain mixes of humidity and air temperature reduce the effectiveness of perspiration, and can kill you if you don’t find shelter.

The higher the temperature goes, the less help are factors like youth, robust health and hydration. Jeff Goodell in his book “The Heat Will Kill You First” explains that as the temperature rises, your body diverts blood from internal organs to the skin to try to cool off. At temperatures of about 100 or hotter, too much blood may leave the brain, causing wooziness or even fainting.

The problem at this point is not necessarily hydration. It’s the lack of blood in vital organs. By around 106 to 107 degrees, drinking water is not the solution. If you don’t find shade and cooler air, seizures can occur. Protein bonds in the cellular structures of blood-starved organs start to break down.

“At the most fundamental level,” Goodell writes, “your body unravels … you are hemorrhaging everywhere.”

It feels like the Earth is undergoing a heat seizure this summer. We’ve been stuffing carbon into the atmosphere for about 250 years, warming it. The ocean has been absorbing a lot of that heat from the air, but seems like it could be reaching capacity, so to speak, more suddenly than anyone predicted.

The climate is unraveling here on Earth. This is not a one-off hot summer. The seizures are going to continue, and they’re going to get worse, if we don’t reduce the heat.

I wonder if this will be remembered as the summer we crossed the River Styx.

Dana Wilde lives in Troy. You can contact him at dwilde.naturalist@gmail.com. His book “Summer to Fall” is available from North Country Press. Backyard Naturalist appears the second, fourth and sometimes fifth Thursday each month.