by Jim Speiser, Special to the Roundup
As America gets slammed each succeeding winter with increasingly snowy and frigid weather, the question naturally arises, “What’s going on? What happened to global warming?”
The answer is, basically ... you’re seeing the results.
As counter-intuitive as that sounds, remember the basic formula that greenhouse gas emissions cause global warming, and global warming causes climate change. It’s that last element that has the climate community really worried. After all, a few degrees hotter here and there, without other effects, wouldn’t be that worrisome, especially if you’re a Northerner these days. But global warming has consequences beyond mere temperature. An increase in temperature means an increase in the total energy of the atmosphere — and energy defines the intensity of climate.
Some of the changes wrought by this new paradigm are predictable — stronger hurricanes, drier droughts, wetter rains, floodier floods, etc. But some are not that foreseeable. What’s happening with winter in America is something that scientists are only now coming to grips with: apparently, we have changed the jet stream.
The jet stream is that band of wind encircling the globe in the general region of the 60th parallel. At least, that’s where it tended to stay up until recently. Those of you old enough to remember back to weather reports in the ’60s may have seen it on the map as a slightly undulating line across the U.S.-Canadian border. Back then it somewhat resembled a snake design around the neck of some Native American pottery, and it kept the frigid temps of the Arctic bottled up where it belonged. Today, it looks more like the Nickelodeon logo, with elongated peaks and troughs, some of which reach as far south as the Gulf of Mexico. What happened to the nice, graceful jet stream of our childhood?
Let’s look at the mechanics of the jet stream. Scientists tell us it is created by the distinct difference in temperature between the polar and temperate latitudes. There is a “tension” there, like two feuding neighbors with a fence between them. In fact, a better way to visualize this tension is to think of those “air curtains” you encounter in some large department stores, the ones you walk through and have to hold your hair in place, lest it be blown about. Somehow, this “curtain” of rapidly flowing air maintains a border between the hot air outside and the refrigerated comfort of the store inside. The faster the air flow, the stronger the border. If you slow down this curtain of air, you weaken the border, and the two different air masses will encroach on each other.
The same is true of the jet stream. Weaken its power, and it will lose its “tension,” and flop around like a fan belt that has come off its pulley. The distended shape that results (think of the fan belt again!) will allow frigid air from the polar region to encroach on points south — WAY south.
So how do you weaken the jet stream? By slowing it down. And you accomplish that by decreasing the temperature difference between the two regions. You can either cool down the region below the jet stream, or warm up the polar region above it, so that the two regions get closer to each other in temperature. There is no doubt that we have done the latter: The Arctic is the fastest warming region on the planet, having seen twice as much overall temperature increase as any other place on earth. And that, scientists believe, is why we are seeing all this winter wackiness.
“But,” you ask, “I thought global warming meant things would be less cold in the winter?” Over the entire planet, over several decades, that’s true. But we are talking about one region in particular (the U.S. is only 6 percent of the Earth’s land mass), and we are talking short term. Two things to keep in mind: (1) Record highs will outpace record lows by a factor of at least 2:1, but (2) there will still be record lows. Even Payson experienced a record low a couple of years back (it was 9 below zero at my house that winter, and my pipes froze and broke) — and Arizona is the fastest warming state in the union!
Indeed, this phenomenon of the changing jet stream may even serve to slightly moderate the inexorable rise of global temperature ... but it will be, and has been, at the expense of more and more frequent Snowpocalypses, Snowmaggeddons, and Polar Vortices. In short ... climate change.