Al Stahler: Climates change
The atmosphere we breathe is complicated, laced with storms and droughts, heat waves and deep freezes. As an analogy, imagine a see-saw – a teeter-totter – built, not for two, but for a hundred – a futuristic teeter-totter, computerized to keep the kids going up-and-down, staying always in balance.
Now imagine this teeter-totter built on a carousel, and the kids playing catch. Playing catch on a carousel is challenging – every pitch is a curve ball.
Up-and-down, round-and-round, our atmosphere is a teeter-totter with hundreds of seats. One seat is the air over California – air that tomorrow will sit over Nevada. Another seat is a hurricane, plowing through the Atlantic. Up and down, ‘round and ‘round, hundreds of kids playing catch on spinning, carousel Earth. Gazillions of things happen at once, but, average out all the ups and downs, pitches and catches … over the whole planet, it all balances out.
I don’t pretend to understand the real atmosphere … no one pretends to understand the whole thing. There’s too much going on, all at once. And much of what’s going on is hidden, high in the air, deep in the sea, under the ice.
To get a handle on this complexity, atmospheric scientists make models of the atmosphere – they use math to describe what happens when you heat things up, cool things down, push or pull on them. The models are super-simplified versions of the atmosphere. And yet, simplified as they are, these model atmospheres are still super-complex.
I freely admit: These model atmospheres are way too complex for me to understand. So complex, sometimes the scientists who put them together have to step back to figure out why the computer is saying what it says.
Building these models requires a deep understanding of how the atmosphere works, requires a lot of judgment calls by the scientists putting them together – what to leave in, what to leave out … how to deal with things unknown.
Some of these computer models have been making some alarming predictions of Earth’s future climate.
Desolation Wilderness, over the crest of the Sierra, is, indeed, desolate. Thousands of years ago, giant rivers of ice, miles deep, bulldozed the trees, the plants, the soil. Visit Desolation and you’re surrounded by evidence of the last ice age – evidence that Earth’s climate can, indeed, change big-time.
It’s now summer in the northern hemisphere, and the arctic will remain the “land of the midnight sun” for another couple of months – star-gazing is hopeless. But come October, night skies over the north pole will grow dark. Suppose we were to head up to the north pole then, wait for night to fall, and look up. Directly overhead, we’d see the north star.
If the sky is clear tonight – or any night soon – head outside, right after dark. Look straight up, and notice the star almost directly overhead. Thousands of years ago, that star shone, not over the foothills, but over the north pole. That star, thousands of years ago, was the north star. And it will again be the north star, thousands of years in the future.
As the years go by, Earth acquires new north stars because, as our planet circles the sun, it wobbles … our north pole points first to one star, then another. And that wobble –combined with several other wobbles – can change Earth’s climate, big-time.
An ice age is a huge climate change. We’ve all lived through smaller changes, like El Niño and La Niña. Does El Niño emerge from the atmospheric teeter-totter just by luck-of-the draw – at random – or is something controlling it? Is there a trigger that pushes our climate over a threshold, into El Niño?
If there is a trigger, it begs the question: Could we human beings, ourselves trigger a change in climate?
Pop a slice of bread into the toaster and the wires inside soon glow, a bright red-orange.
Another color of light also comes off those wires, a color our eyes can’t see. Put your palm up toward the wires, and you can feel that invisible light: Infrared – invisible to our eyes, but “visible” to our skin, as heat.
Infrared works a lot like the colors we can see … it reflects off a mirror … focuses with a lens … you can block it out with your hand. But infrared is very different from the other colors, in one important way.
Several weeks ago, we were trapped under a dome of hot, high-pressure air … not unlike the dome that had us pinned down this week. Such high-pressure domes rotate slowly, clockwise.
At the same time, several weeks ago, the remnants of hurricane Elida were spinning off Baja, spinning counter-clockwise. The opposite spins made it easy for the hurricane remnants to feed moisture into our dome … moisture that turned into storm clouds … that bred lightning … that ignited the Jones Fire.
The moisture over our heads also did something to our nights, and that relates to how infrared is different from the visible colors of light. All the visible colors pass right through water … but not infrared. Water sucks up infrared, which kept the humid nights warm.
Water is a powerful greenhouse gas – absorbing infrared, water keeps the air warm. Fortunately, water doesn’t remain long in the air – it rains out.
Carbon dioxide (CO2) is also a greenhouse gas. It’s not nearly as powerful as water, but it does not completely rain out … carbon dioxide accumulates.
Two questions: How much will CO2 ultimately warm the air … and could that warming push the planet over a threshold, and trigger a change in climate?
One of the pleasures of studying nature – a pleasure I enjoy sharing in my essays in The Union, and on KVMR – is that when we see nature in the raw – in the atmosphere, in the woods, in the seas – we can connect it to things we see in our kitchens, our yards, our playgrounds. I apologize that I cannot add to anyone’s comprehension of climate models … but hope I can still be of service in explaining the basic laws of the universe. Written into the models, these are the basic laws that rule the atmosphere, that control the universe.
Al Stahler enjoys sharing science and nature with friends and neighbors in The Union and on KVMR-FM; teaches classes for both kids and grown-ups; and can be reached at firstname.lastname@example.org.
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