As I sit in 90-degree heat typical of Washington, D.C. in midsummer and a so-called “heat dome” hovers over much of the United States, I am reading the following:

At 11 or 12 degrees [Fahrenheit] of [global] warming, more than half the world’s population, as distributed today, would die of direct heat. Things almost certainly won’t get that hot this century, though models of unabated emissions do bring us that far eventually.

That implies one of two things: A lot of migration or a lot fewer people. This second thought is suggested in the observation above, but few people want to come out and say it: What we are doing to the climate, to the air, to the water and to the soil, and thus to ourselves, on our current trajectory implies a dramatic decline in human population as multiple crises converge and our ability to cope with them dwindles.

As it turns out, the number of 90-degree days in Washington’s summers has been on a steady rise. And even though the record for the longest streak of days with temperatures reaching above 90 wasn’t broken this time—only 20 days in a row instead of 21—those 90-degree days are coming sooner in the season, and there are more of them.

“Okay, so it’s hot,” you may say. “We’ll live. We’ll live by staying indoors in the air-conditioning, by drinking more water, by taking more cold showers, by simply taking it easy in the hot temperatures of midday, right?”

I was in the great heat wave which hit Chicago in July 1995. I was staying with friends whose second-floor apartment had no air-conditioning. None of us believed air-conditioning was particularly healthy for humans and generally avoided it. We were all quite a bit younger, of course, and so held up quite well the first three days since we had all already adapted to summer temperatures by forgoing air-conditioning.

But as the heat wave continued, it wasn’t the daytime temperatures—which were over 100 degrees—that finally got to us. It was nighttime temperatures which only fell to the mid-80s. Even with windows open and fans roaring, it was difficult to cool down, and therefore difficult to recover from the scorching daytime heat.

On day six we walked up to university campus where my friend worked and sat in the faculty lounge while he took care of some business. When exactly he joined us, I don’t know, because the rest of us quickly fell soundly asleep on the couches in the almost icy cold room and slept for about three hours. I hadn’t realized how much my body needed to cool down to recover from the heat.

So now, I’m trying to imagine what might happen if other systems which make living in this kind of heat failed simultaneously with the coming of such a heat wave. Let’s say the power goes out, not just briefly, but for a prolonged period and there is no air-conditioning.

Fossil-fueled electricity generation relies on copious amounts of water. If those supplies, which are often taken from rivers, are low in midsummer because of drought, plants may not be able to operate or at least operate at full capacity. And then, there is the general state of America’s electrical grid which the American Society of Civil Engineers (ASCE) gives a D+ in its 2017 Infrastructure Report Card, the latest available. This creaky system we call the grid isn’t keeping up with our needs. Perhaps the most egregious example is the California grid which sparked many deadly wildfires during the severe drought that gripped the state in the last decade.

How about public water systems? The news is not good. The ASCE gives America’s water systems an even lower grade, D. Will water interruptions increase over time as our neglected system continues to degrade? The savage decline in municipal and state government revenues in the wake of the worldwide pandemic and economic depression doesn’t bode well for renewed investment in public infrastructure of any kind.

And, then there is the overall effect on agricultural productivity. A few 90-degree days in summer isn’t going to ruin crops. It might even help them. But persistent heat and drought could lead to drying out of agricultural soils and inadequate water for rainfed crops. And, the opposite—widespread severe flooding—could also bring trouble to the farm fields. Both are emerging consequences of ongoing climate change.

But, when food supplies are inadequate, excessive heat may seem a secondary consideration.

What I’m getting at is that when we think of adapting to climate change, we often think of tackling discreet tasks one at a time. But the reality is that we are already faced with multiple systemic threats across many domains. Addressing those threats will involve understanding that our entire way of life is unsustainable and therefore cannot just be tweaked slightly here and there to make it sustainable.

While the heat dome which hangs over most of us denizens of the United States cannot be said to be “caused” by climate change, it may represent a more and more frequent feature of our climate-disturbed world. In the midst of this disruption, we may fantasize escaping all this either through technological fixes or leaving planet Earth altogether as some so-called visionaries suggest.

As I was watching the film “Gravity” last night on television, I was reminded that such deep space fantasies are nonsense. Earth’s biosphere is the only place permanent human habitation is viable. It’s the only environment to which we are adapted because we were forged in its evolutionary processes. That’s why in the film, after swimming to safety from her sinking spacecraft, astronaut Ryan Stone hugs the shore where her harrowing journey back from space comes to an end. We should take our cues from her.

Photo: Orange coneflowers (Rudbeckia fulgida), faded through the summer heat of 2011. Author “High Contrast” via Wikimedia Commons https://commons.wikimedia.org/wiki/File:Rudbeckia_fulgida_during_the_Summer_heat.JPG