Climate Change, the Winter of 2013-14, and Global Warming

 

While I’m fully aware that linking these subjects together is a hazardous undertaking — even speaking of “global warming” is no longer politically correct — still, this winter’s brutal weather should even give us northerners, who are supposedly used to such extremes, pause to reflect.  After all, most of us, despite our isolation, are more or less in touch, thanks to TV and the Internet, with what is going on in other parts of the country or even in some other places in the world. We hear of gigantic typhoons in the Philippines, extensive flooding and devastating storms on the southern coast of England and other parts of Europe’s Atlantic coast not unlike Hurricane Sandy’s 2012 impact on the US eastern coast.  And while the frequency of tornadoes may not be greater, their size and violence seems to have increased.  Lately we’ve had uncharacteristic snowfalls in the southern USA, and until recently, California has experienced the worst drought ever since records have been kept.  What is going on?

        Well, as I may have mentioned before in writing about this subject, when I first heard of the term “global warming” nearly thirty years ago, we were also told that at least some scientists believed its arrival would be most noticeable through wild extremes in the weather, with some summers unusually hot, while others unusually cool.  The same goes with the winters, at least for awhile.  Less than a decade ago, we were also told that Michigan’s winter weather would generally become warmer and wetter.  This became very noticeable with the kind of events we experienced here around the Pigeon River Country when in both March and December of 2012 heavy wet snow brought down the power lines, snapping off tree limbs, and in a few cases, even toppling whole trees, yet temperatures remained generally mild. The rest of the winter of 2012-13 was better behaved, with frequent thaws and very few subzero temperatures except for a few mornings in February (like Feb. 9, 2013, which started off at -15F but by the next afternoon it was +35F).

        But this winter of 2013-14 has been brutally different, starting early on December 16th when the morning temperature here was -17F and thereafter no above freezing temperatures were seen except during a brief thaw on January 11-13 only to go back down to -21F on the morning of Jan. 21st.  While the thaw lowered the snow level a few inches, more and more fell, as well as blew in on strong winds which, combined with a lack of crust-forming sunshine, has made cross-country skiing difficult, if not downright dangerous at times, given the wind-chill. Early in the morning of February 27 it was -32F outside my cabin, and on March 3rd it was -26F at sunrise. Since then, March has seen temperature as low as -26 (Mar.3) and high as 53 (Mar. 10). With only a few brief thaws that compressed the snow rather than melting it, at this point in time (Mar 15) I’m still more or less “snowed-in” with my Jeep parked a half-mile away -- next to the county road.       

        Does this mean that overall, that there really is a climate change taking place? And if so, how can it be in the direction of global warming, even while some, given this winter’s weather, are beginning to wonder if we aren’t experiencing the onset of a mini-“Ice Age.” Some were even talking about this weather being caused by what seems to be a lull in sunspot activity at a time that the Sun should be at the peak of its 11-year cycle?  But the week after I heard this theory it quit snowing and the sky cleared enough that I was able to check with my small telescope equipped with a sun filter and to my surprise there was one of the biggest sunspots I’ve seen in years! 

But even if there is a strange lull in the Sun’s 11-year cycle, does this mean that overall, the earth will not continue to warm up?  After all, history has recorded mini-“Ice-Ages” before, most noticeably in the late 1600s, but that did not stop the over-all warming trend since the last major Ice Age began to thaw out about 20,000 years ago.  So given this overall trend — with the next major Ice Age not scheduled to begin until about 30,000 years from now — what kind of weather can we expect in the meantime?

        To try to predict what will happen, even in the short term, we first have to understand what is going on right now. And to do that, we need to try to understand a number of separate things that seem to be going on all at once.  These are, first, the increasingly wild behavior of the high altitude jet streams; second, the polar vortex and its oscillations, and, finally, the suspected relationship of the later to the stratosphere and what seems to be going on way up there. 

 

A. The Jet Streams  

I mention “streams” in the plural, as there are four of them, two south of the equator and two north of it, each circling the earth from West to East.  They are caused by a combination of the earth’s rotation and the heating of the atmosphere by solar radiation.  They were only discovered after high altitude aviation began in the middle of last century, but now, better understood, they can be seen as acting something like conveyor-belts that tend to drag the air closer to the ground along with them, thus dominating our short term weather patterns.

The polar jet streams are generally located at about a latitude of 70ºN or 70ºS — depending on which pole we’re talking about. But a lot like a wiggling snake, they can swing widely from side to side. The altitude of the polar jet streams fluctuate between about 23,000 to 36,000 feet above the surface of the earth. The north polar jet stream tends to mover further north in the summer and further south in the winter months, as the south polar jet stream does just the opposite. The polar jet streams are also generally the strongest, compared to the two subtropical jet streams, which tend to follow tracks about 30ºN & 30ºS respectively, but at higher altitudes ranging from 33,000 to 45,000 feet, and are generally weaker.  In any case, they are a real boon to aviation — providing you are flying west to east.

        However — and this is the really wild card in particular — each jet stream is susceptible to deflection that often throws them even farther off-course.  This due to what is called the “coriolis effect”, which is the tendency of any spinning object to throw off debris or parts of itself (think of a spinning tire throwing mud from its treads).  In the case of the jet streams, this deflection tends to be toward the equator, which in our case, in Northern Michigan (at 45ºN), means that when the northern polar jet stream gets especially rambunctious, we are apt to get hit with nasty weather from the north or northwest.

        But it’s not just the polar jet stream that affects us here.  Since the normal track of the northern subtropical jet stream is only about 15 to 20 degrees south of us, it also often affects us here in Northern Michigan, as when this jet stream wanders northward and we experience sudden thaws in the winter, or even tornadoes and other violent spring and summer weather events. 

Then there are the effects, even farther away, of what is called the “Northern Pacific Oscillation” which in turn seems to be influenced by the el Niño (so named when unusually warm water, originating in the southwest Pacific finally reaches the west coast of South America around Christmas time) or, in some years, its contrarian cooler-water sister, la Niña, takes its place. Either way, they eventually affect even the North American west coast. Normally, these Pacific Ocean events don’t affect us much here up in the Great Lakes State, but recently, this year and last, la Niña has been dominant, and when that happens California and the American Southwest get very little moisture, because the ocean temperature and currents also affect the subtropical atmospheric jet streams. 

No one seems to know just what causes the el Niño/la Niña oscillation.  Most climate scientists think it must be connected to the warming of the atmosphere, thus the ocean beneath, but I came across a website claiming it all was result of volcanic eruptions under the Pacific Ocean. But when those ocean currents are cool rather than warm, then the northern subtropical jet stream over the Pacific ocean sometimes veers off sharply to the northeast taking whatever wet weather that was destined to be rain for southern California and snow for the high Sierras and delivers it instead far to the north, even to Alaska and the Yukon territory. And when this moist air from the Pacific moves that far north, then, particularly in the winter months, it can often be deflected southeastward, resulting in heavy snowstorms in the upper Midwest.  Once this happens, as it did this past December, things get even worse, as when around New Years it was followed by a new shot of sub-Arctic cold air reinforced by the latest culprit, the mysterious “Polar Vortex”.

 

B. Polar Vortices

Again I switch to the plural (or “vortexes” if you must) not just because they exist at both poles, and are usually confined to latitudes north (or again south in the case of Antarctica) of the polar jet streams, but because our Northern Polar Vortex actually has two major centers of vortex activity, which describes what happens when you have an area where the cold Arctic air tends to stay in one place. For North America this is concentration tends to be near the northeast corner of the continental land mass, close to Baffin Island — just west of the iciest location in the western northern hemisphere, which is Greenland. The other northern center of vortex activity, in this case for the Eurasian continent, is the northeastern corner of Siberia.  This is especially significant in that it is two Russian scientists who seem to have been among the first to call attention what is really going on.

        Meanwhile, one of the best sources for information as well as speculation as to what is happening with the Polar Vortex is Dr. Richard (“Ricky”) Rood at the University of Michigan.  His “Climate Change Blog” on the www.wunderground.com website is full of charts depicting the movements of the Northern Polar Vortex and the effects it has had on the weather in all directions to the south.  Generally speaking, the “oscillations” of these vortices vary from a “negative phase” characterized by high levels of barometric pressures in the Arctic with much lower pressures to the mid-latitudes such as we are near Gaylord at 45ºN.  This forces the cold Arctic air south. The “positive phase” is just the opposite, where the cold Arctic Vortex remains in a low pressure “sink” up near the North Pole where we would prefer it to remain while down here the temperatures remain milder and hopefully, the skies remain sunnier. By now it seems obvious that the terms “positive” and “negative” are not descriptive of the barometric highs or lows, but rather of our own comfort in the mid-latitudes, as well as the well-being of the polar bears up where they call home. Unfortunately, for us as well as for the bears, as we have seen this winter, it doesn’t always work out that way. It is at this point where the Russians come in.

         In 2010 Vladimir Petoukhov and Vladimir Semenov published a paper in which they called attention to the diminishment of Arctic Ocean sea ice and linked it to the increasingly cold winter weather in the northern continents.  Add to their data what NASA, even back in 2001, had already gathered that indicating that changes in the temperature of the stratosphere had begun to affect the behavior of the Polar Vortex or Vortices.  And since the paper by the two “Vlads”, other similar studies have appeared detailing how European weather has been affected.  This year Northern Scandinavia has been unusually warm, while farther south, far Western Europe and even parts of Northwestern Africa have been unusually cold, all again apparently associated with vanishing Arctic sea ice.  Nor can we expect that this is all over yet, for this year, as studies by NOAA taken during March of the years 1983-2006 seem to indicate that during the latter part of the winter especially, the location of the polar vortices can oscillate all over the place. So what does all this add up to, or what does this all mean?

 

C. Global Warming and the Stratosphere.

I’ve saved discussion of Global Warming until last, hoping that by now the reader might be convinced I’ve done some homework on the subject.  Nor am I going to get into the reasons that Global Warming seems to be happening.  I’m going to confine my comments to what the scientists are observing.  And to understand what they are observing, we have to know something about the basic structure of the Earth’s atmosphere. The Earth’s atmosphere is generally thought of as consisting in five layers, these separated by thin transition zones.  On top is the ionosphere, full of charged particle of energy where auroras often appear.  Below that is the thermosphere where the temperatures reach up to 100C.  Next is the Mesosphere where the temperature can be as low as -100C.  But for the purposes of this discussion, the two bottom layers count the most: first the one closest to the Earth, is the “troposphere” in which we live, and then, on top of that, the “stratosphere”.  The troposphere is generally warmest at the earth’s surface, and coldest (around -40C/-40F: the point where the two temperature scales coincide) where it meets the transition zone to the stratosphere, at altitudes ranging from about 45,000 feet over the equator, to 30,000 feet over the poles. Way up there, contrary to the troposphere which gets colder the higher up you go, the stratosphere surprisingly gets warmer the higher one goes, culminating in temperatures reaching nearly 0C/32F at an altitude of about 50 miles above the earth. Or at least that’s what the data has always seemed to indicate in past decades.

        However, what scientists have recently discovered is that the stratosphere seems now to be getting colder overall, and that this is most certainly due the much-publicized “greenhouse effect” discovered over a century ago when it was discovered that carbon dioxide and other greenhouse gases concentrated near the ceiling of a greenhouse tend to block the passage of whatever heat is generated lower down in the greenhouse.  The climate scientists are convinced the same thing is happening at the top level the troposphere, both as indicated by air samples taken at its higher levels just below the transition zone into the stratosphere, and by concentrations of CO2 closer to earth which, as measured in air trapped in ice samples from many centuries back in the Greenland and Antarctic icecaps.  These indicate the present concentrations of this gas about 1.4 times higher than before the industrial age began and is higher than any level found from any of the past warm periods between the Ice Ages over the past 800,000 or so years.   Thus they conclude that all the heat radiated from the earth is being trapped — much the same as by a greenhouse roof with its concentration of CO2 — with the result that over all, the stratosphere, which normally would have been warmed by that radiated heat is actually getting colder.  So far so good, if you consider gradual warming all over the Earth something to celebrate.

But it is at this point that we seem to run into a strange deviation. A year or so back some climate scientists began to report that rather than getting colder, the stratosphere over the Arctic seems to be getting warmer! If so, why is this?  The obvious reason would seem to be that the melting of all the sea ice in the Arctic Ocean as well as the melting of the inland glaciers is causing less of the Sun’s rays to be reflected away from the earth’s surface but instead to be warming up the Arctic Ocean and adjacent land surface, thus radiating heat up through the thinner atmosphere over the poles on up into the stratosphere.  Or could it also be (and this is my speculation) because both the troposphere and the stratosphere being thinner over the poles, so too is the Greenhouse effect up there is less severe and the overall effect is somewhat like a chimney, allowing the radiated heat from the surface of the Arctic areas to escape further up into space? In any case, it seems that the polar vortex or vortices, which generally have consisted of a concentration of cold air under low pressure near the poles, are now being destabilized and more easily dislocated by the combination of factors involving the jet streams and ocean currents like the la Niña phenomenon, with the effects described in 2010 by the two Russians and now being felt in North America and all across Eurasia.  

All this leads me to ask two questions.  First, what happens when the continued warming of the Arctic regions starts melting all the permafrost up there, releasing vast amounts of methane gas, thus greatly increasing the greenhouse effect over the North Polar regions?   Will this accelerate the warming of the thinner Arctic stratosphere as well, or on the other hand, do just the opposite?

Second, what about Antarctica?  What will happen down there?  We already know that vast amounts of the sea-ice adjacent the land mass there is breaking up at an alarming rate.  But the land mass itself, generally far underneath the polar ice cap, will no doubt take many centuries to unthaw, and when it does, a good part of it will turn out to be well below sea level.  So apart from the major rise in sea level that all this melting is going to cause, eventually dislocating a good part of the world’s human population, it would seem to me hard to predict how much additional methane is trapped underneath the South Pole’s ice cap. But we do know that this Antarctic land mass probably once had a tropical climate like that once had by Australia, from which, thanks to plate tectonics, it became detached and drifted southward billions of years ago.  But thinking on that time scale, who knows where North America or any other place will eventually end up on the Earth’s surface?  And will any humans still be around to witness whatever happens?  I very much doubt it.

So what can we expect in the more immediate future — let’s say the next century or two?  Obviously some people are going to have to move from their sea-side homes very soon, in fact it is already happening in parts of Norfolk VA and Long Island, NY.  (And people have to be out of their mind to make long-term investments in real estate in South Florida.)  And the rest of us are going to have to get used to, I fear, both a somewhat changed environment as we experience more wild extremes in our weather.  For one, I was hoping this extreme cold, the most sustained cold-weather period I’ve ever experienced in thirty-three years of living up here, would at least stem the invasion of wood-ticks we’ve experienced in recent springs and summers due, the experts say, to a string of mild winters. Hibernating ticks are supposed to survive sustained temperatures down to 10F but not much under. But apparently all the snow gave the ticks ample insulation from the cold, or else the species has suddenly mutated. Meanwhile, the climatologists are still telling us that that we haven’t seen anything yet.  Couple of summers from now, maybe tarantulas in our tomato patch?

        Nor are there any simple answers.  If researching for this article has taught me anything, it is that climate science is considerably more complicated than, and undubtedly more unpredictable than, let’s say, nuclear physics.   So, in the meantime, how long will this period of instability last?  It is hard to say.  If climate change is something that can only be measured in decades, I suspect that overall global warming in general is a change that can probably only be measured in terms of whole centuries.  If so, it is unfortunately likely to be with the result that, like the proverbial frog in the cauldron of slowly heated water, we will gradually find ourselves parboiled without having ever realized we were in serious trouble.

        On the other hand, we know that however drastic climate change turns out to be, at least some humans will probably survive, just as our remote ancestors, or at least those who were smart enough, not simply survived, but even evolved into what we are today, partly by making the changes that were necessary to cope with or even take advantage of a changing environment.                         

 

R W Kropf      3/15/2014    updated 6/1/14                 Climate Change.doc/html