The biggest loss of containers from a container ship (that didn’t just plain sink) happened a few days ago as the Svendborg Maersk was battered with hurricane like conditions including Waves Of Unusual Size generated in the Global Warming Enhanced megastorm, while at the same time tornadoes, some snownadoes, touched down in various places in the US.
Snowstorms and cold weather chills swept from the Midwest to the East Coast in January, closely followed by conservative media snow-trolls casting doubt on global warming. But what the conservative media didn’t mention was that the world as a whole was experiencing warm temperatures, leading to January becoming the 347th consecutive warmer-than-average month and the fourth warmest on record.
On February 20, the National Oceanic and Atmospheric Administration (NOAA), released the findings that January 2014 experienced global temperatures 1.17°F warmer than the 20th century average, making it the fourth warmest January on record. NOAA data shows that the last time the planet experienced a month colder than the 20th century average was February 1985 — 29 years ago.
How could this be, when Fox News is telling you that the snowstorms in the United States are a reason to doubt global warming? The answer lies beyond the lower 48 states, which make up only 1.5% of the Earth’s surface. While some regions in the contiguous U.S did experience a colder-than-average month (none a record cold month), most of the globe did not:
Last night I attended a talk by meteorologist Paul Douglas, at the Eden Prairie High School. The talk was “Weird Weather: Minnesota’s New Normal? Our Changing Climate and What We Can Do About It,” and it was sponsored by Environment Minnesota, Cool Planet, and the Citizens Climate Lobby. I didn’t count the number of people in the audience but it was well attended (over 100, for sure). Extra chairs had to be brought in.
You probably know of Paul Douglas either because of his own fame or because I often link to (or facebook-post) his blogs at Weather Nation or the Star Tribune, and I frequently post his videos. Paul is an Evangelical Christian Republican who insists that we must adhere to the data and the science. He is outspoken on climate change, global warming, and science denialism, and he is sincere, thorough, and forceful in these areas. I consider him to be a very close ally. The contrast between what Republicans seem to think as a cultural group, and what Evangelical Christians seem to think as a cultural group, and what Paul advocates makes him, in his own words, a Human Albino Unicorn.
The talk, as something organized by three environmental activist groups, had the usual suspects in attendance. I recognized several fellow activists from the Twin Cities area, including individuals from 350.org and Obama’s OFA. I had the sense that I was attending a Democratic Farm Labor (that’s what we call Democrats ‘round these parts) convention being run by a Reasonable Republican.
Needless to say, Paul provided an excellent presentation that would have provided any skeptic sitting near the fence a gate to pass through when the moment was right. His talk would have likely convinced any dyed-in-the-wool septic in attendance to at least be quiet about the skepticism and let others take the conversation for a while. Paul tied together several reasons to respect the science and to act on it, touching on diverse perspectives including personal morality, concern for our children and grandchildren, business acumen, responsibility for the Earth’s environment, conservative political thinking, and (briefly, he did not belabor this point) religion.
Since I’m all into climate change and stuff, and give presentations on the topic myself, there wasn’t much new that hit me on the head, though I saw a lot of other heads being whacked with facts and ideas in the room. But there were two things that gave me a double take. They were both brought up in the question and answer period.
One came as part of the answer to the question, why isn’t there more climatology, and in particular, climate change, in with the weather reporting on local TV? I should note right away that this is one of the reasons you should read Paul’s blog. You get the weather AND the climatology. If you are in the Twin Cities area, his Strib Blog is the place to go. If you are elsewhere in the US or beyond, his Weather Nation blog is the place to go. There is a lot of overlap but somewhat different regional coverage. Anyway, Paul’s answer included this: On news TV, global warming is toxic. Meaning, specifically, stating the basic fact that global warming is established science is not really allowed on standard news TV, local or national. The False Balance sells, admitting the facts is boring. More importantly, stating that climate change is real and important will piss off 30% of the audience and the people running the news shows don’t want that. The anchors, including the weather reporters, are to be beloved, not reviled. So “just don’t do that” is the policy in newsrooms.
The other whack on the head was in relation to a question that I thought at first was a bit obnoxious but then I realized it was one of those questions that IS obnoxious but usefully so, and necessary. The question was, in short, “Is there anybody in this room that didn’t already believe in global warming before this talk … was anyone’s mind changed?”
One person raised their hand to indicate a changed mind (everyone cheered) but this apparent fact was left on the table: This talk didn’t do anything but reinforce everyone’s existing position. That was a bit depressing at first.
However, I think the implication and factual basis of that question were wrong. First, there were probably several climate change denialists in that room, but they simply chose not to raise their hands either because they would have been deeply embarrassed or because their mind was not changed. I recognized one person that I’ve encountered before who is a denialist, and he remained silent. I have given talks on climate change attended by people I know are denialists and they’ve stayed silent or asked questions that did not indicate their denialism. So, yes, there are people in the audience who do not “believe in global warming” and I suspect a talk like Paul’s would have an effect on them, eventually.
Also, this: Nobody should “believe in global warming.” That’s where Paul separates his own beliefs (i.e., that there should be Republicans at all 🙂 … or his religious beliefs which are based on faith) and a scientific approach to life, including both business and climate. A different question might have been, “Was there anything in Paul Douglas’s talk that you didn’t know before, about climate change, that you now know? Did you learn anything new either about climate or about how to talk about climate, in this talk?” The answer to that would have been, for almost everyone in the room, “Yes, many things.”
And this is a very important reason why “preaching to the converted” is important. Anti-climate science industrial interests spend hundreds of millions of dollars annually on public engagement to develop and shore up their political position. Hundreds of millions of dollars a year buys a lot of rhetoric, but it does not buy one drop of truth. But truth by itself is not enough. Grassroots organizing and the power of citizenry, when armed with the truth, is enough to effect major change if it is sustained long enough over a sufficient range of the population (and done well). Last night’s talk was a highlight moment for local and regional activism in support of the planet we live on. Those who attended will keep Paul’s talk with them for decades, and it will supply them with tools and ideas, and perhaps most importantly, inspiration and hope, regardless of their personal staring point.
For the first time in weeks we are experiencing warm weather in central Minnesota (it is now 21 degrees F) with a bit of snow off and on. But elsewhere there are interesting things happening. First, in far northern California and the Pacific Northwest there will be rain. A LOT of rain. That’s great because it will help a little with the drought. But, it will also probably cause some severe flooding.
Also, everywhere on the east coast from Atlanta up to New England is experiencing some kind of bad.
A friend of mine in the Raleigh-Durham area told me last night that he drove off the road three times in three miles, and normally he does no drive off the road more than once in three miles! I can’t be sure of the attribution of the photo shown here of the Fiery Snomageddonapocalypse, but it seems to be someone from North Carolina. Found on facebook.
More than three quarters of a million people have been without power across 14 states. New York City and DC are getting hammered or will soon.
You all know this from the news. I just wanted to add some context.
Here I’ve combined an estimation of precipitation over the next 7 days from here, with a map of the Jet Stream from here.
Published on Jan 28, 2014
WeatherNationTV Chief Meteorologist Paul Douglas looks at the devastating winter storm impacting much of the Southeast. Multiple accidents have been caused by the treacherous conditions. Schools are closed through Wednesday across the affected areas. Multiple states have declared States of Emergency, including Georgia and Alabama. Stay safe!
Published on Jan 24, 2014
“It seems like the weather, increasingly, is getting stuck.” Meteorologist Paul Douglas explains this weather pattern that seems to be stuck in a rut. Swells, drought and a polar vortex! Learn how it is impacting everywhere from Hawaii/Alaska all the way to Europe. The Winter Olympics may feel more like the Summer Olympics!
Extreme weather events of all kinds seem to be more common now than they were then. By now I mean the last five to ten years, approximately, and by then I mean … well, before that. This is because of global warming.
The current Colding caused by a wandering Polar Vortex (which I’ve heard Rush Limbaugh has declared to be a liberal plot … thanks Obama!) is probably a result of changes in the nature and configuration of the jet streams and related air masses, as discussed here. Warming caused by the release of fossil carbon, mainly as Carbon Dioxide, has affected the Arctic more than most of the rest of the planet, and this has changed the nature of major air mass movement which, in turn, has disrupted the jet streams, which has caused what we call weather whiplash. If you would like to see an example of weather whiplash, you can probably do so by looking outside because it is happening all over the place all the time. Well, it seems that way anyway. Let’s just say that it is happening often enough that the lack of weather whiplash may well be newsworthy.
Peter Sinclair of the Yale Climate Forum has a post and a new video that puts a lot of this together. Here’s the video:
Also, check out my novella, Sungudogo, HERE. It is an adventure story set in Central Africa which ultimately turns out to be a parody of the skeptics movement. It seems to have struck a nerve with a few of the skeptics, while others seem to have enjoyed it. Who knew?
The best way to not look like an idiot is to shut up. Works every time. Why just a few minutes ago I said something really stupid because I confused UPS and USPS. Should have just kept my mouth shut, but I didn’t.
This time of year a lot of people start sounding like idiots, quite possibly because they are idiots (but see below for alternative explanations), when it comes to global warming. For example, someone who may or may not be a “global warming denier” (i.e. a person who does not believe in physics) sent me, out of the blue, this string of tweets:
First he tells me that the ice in the Northern Hemisphere in mid December is extensive. He says that I can see “the recovery” and points out how extensive the recovery is, and how much snow there is too.
This is the somewhat more elaborate version of, “It is cold out today therefore there is no global warming.”
This is December, which means we have data through last November for the last several year compiled on a monthly basis by NASA. Here’s the last several years of Novembers, showing that Novembers are getting warmer (for background click here):
Turns out it’s the hottest November in this extensive database of Novembers, globally. Still, though, November was very cold in the northern hemisphere compared to July! That, of course, is because July is pretty near the middle of the warm season, and November is getting close to the cold season, in that hemisphere. I predict that when the data come out, December will be even colder than November!
The “recovery” my twitteriffic friend points to is the idea that Arctic Sea ice has recovered after having a couple of bad years. Here’s the story on the sea ice (click here for background). First, let’s look at Arctic Sea ice as it melts and reforms every year, in surface extent, for something close to ten years in a row a bunch of years back. The thick like is for reference. All the thinner squiggly lines are each for one year, back in the day:
Then, a thing happened we call “Arctic Amplification” in which global warming caused the northern regions to get warm, just like the entire surface of the Earth is getting warm, but relatively more so. This includes reduced sea ice that forms and melts every year, like in the graph, as well as permanent melting of the thicker multi-year ice, decrease in overall snow cover, and increase in the temperature of the northern sea. The effects on sea ice is seen in the following graph, which shows through 2011. The thick line is still there for reference. Notice that the pattern from 2002 to 2011 is distinctly different from, with less ice all the time, than the pre-2002 pattern. This is because of global warming, and it is an excellent signature of “Arctic Amplification.”
Notice that the last chart only goes through 2011. One thing that happened last year, for the 2013 melt season, is that a lot of science denialists such as my tweety friend (see above) went on and on and on about how Arctic sea ice had “recovered” in 2013. They used this series of data to make their case. Look at this graph:
Notice that when we look at the march of melt and formation of Arctic sea ice for 2013, it looks like one of the worst years of the worst. Yet climate science denialists called this a recovery. They are still calling it a recovery, and now, apparently, they are even calling “Winter” a “recovery.” This, without a doubt, makes them look like idiots.
There is a reason that they do this. Not good enough of a reason to make them not look like idiots. Rather, if you look at this reason they look even more like idiots than you might have been thinking unless you want to give them the benefit of the doubt and call them dishonest instead. Either description seems to fit. Here’s the thing. If you add the year 2012 on to that last graph, it looks like this:
The year 2012 is the dotted line that is way way more intense in terms of melting than any other year ever seen. If we remove that year from consideration, we can see that Arctic sea ice has been melting more and more with every year being highly likely to be worse than any previous year at least for several months (but not always) right up to and including the present year. But if you add 2012 into the mix, we can easily say the same thing but then we also note that 2012 was an exceptional super-melty year.
Going back to all messed up and melty from an unbelievable extreme year is not a “recovery.” Not even a little.
Tweety Bird (the guy cited above) makes the mistake of thinking that if it gets cold or snowy during the Winter than global warming is over. But actually, the extreme snow cover we’ve seen in some areas, and some of the extreme cold, is probably due to global warming. Confused? It is, in fact, a little confusing but you can learn why this is and not look like an idiot! Let me show you.
We’re not completely sure of this, but here’s what climate scientists are currently thinking and all indications are that it is likely true. Normally the air around the Earth can be thought of as being in large rotating bands demarcated by jet streams, and weather patterns move along those bands bringing dry, wet, whatever, conditions as they do so. The bands and the jets form because the tropics are warm and the poles are cold and weather is all about the movement of tropical heat towards the poles. But if you change some of the key variables in this system, like the size of the planet or the amount of the atmosphere, for example, the system looks different; perhaps a different number of these big bands forms (Earth has several, Mars has two, for example) or some other attributes change.
It turns out that if you decrease the amount of difference from tropical and temperate regions vs. the poles, in terms of temperature, the jet streams get all wiggly and cause northerly air to reach far to the south in some places and southerly air to reach farther north in other places. This causes unexpected weather like snow in Egypt. It also may facilitate the formation of nasty storms. More importantly, perhaps, is that the wiggles in the jet stream stay in place for long periods of time, or move very slowly, and this causes storms to stall in place and we get weather events like the flooding we saw in Colorado, Calgary, Central Europe and other places over the last year. Or Sandy’s being steered int NY/NJ/Conn last year. That sort of thing.
So if it was Summer and it is now Winter, that does not mean that global warming isn’t real. If there is a strange weather event that causes snow in Cairo or a “500 year flood” in Boulder, that is an effect of global warming, not evidence that global warming is not real. For global warming to not be real some very basic physics need to not be real. The basic physics are real. Your idea that global warming is a fiction is not real. You might have good intentions (this is doubtful, more likely you are a jerk for wanting our children to suffer the consequences of your actions) or you might be misinformed (this is doubtful — if you know enough to use dog whistles such as “recovery” you can’t claim this honestly) or you might be economically motivated (there are those who are paid to deny global warming, millions have gone into this form of science denialism). Or maybe you really are an idiot. In any event, remember that there are consequences. Short term, you’re not going to be taken seriously. Long term you are helping to ruin the planet. Either way, please consider the advice given at the beginning of this post.
Here are a few related items from here and elsewhere on the internet:
Over the last 48 hours or so a weather system slowly moved across the southern Dakotas, Nebraska, Iowa, and Minnesota. It was in part shaped and positioned by the jet stream, and it was so slow moving because of the unusually curved nature of the jet stream. This is very much like what happened a few weeks ago in Colorado, but with less of an effect. Nonetheless, there was a damage and injury causing tornado in Nebraska and Iowa, and nine inches of rain in Winona, where there was some very inconvenient flooding. The huge multi-foot snow storm in the Dakotas was part of this system. People died in that storm.
And yes, folks, this is global warming. A warming earth meant a warming Arctic. The Arctic warmed to a certain point and then runaway feedbacks caused the Arctic to suddenly grow much much warmer than it was, and more importantly, the Arctic became relatively warmer compared to the rest of the plant, a phenomenon called “Arctic Amplification.” This changed the way extra heat in equatorial regions moves towards the north pole, and this in turn caused the jet streams to change their configuration so they get all bunched up (in these things called “Rossby Waves”) which causes large weather systems, usually either very dry or very wet, to stall in place or move very slowly. We were getting a mini-flash drought while Boulder and environs were getting flooded. And now we are getting flooded while our neighbors are being buried under three feet of snow. The rapid back and forth between extremes, and the more extreme nature of the extremes, has been termed “Weather Whiplash” by meteorologists.
Welcome to the new normal! Most of the time it will just mean a change in when you water your lawn. Other times it will mean footing the bill to rebuild all the roads, and a death here and there. Sometimes it will mean much more. Stay tuned.
We call it “weather whiplash.” This is not just meteorologists being funny. It is a phenomenon that perhaps has always been with us to some degree, but that has recently become much more common, apparently. If you were under the impression that there is a lot of strange weather going on out there, you may be right, and weather whiplash may be the phenomenon you’ve noticed. Importantly, there is good reason to believe that weather whiplash is the result of anthropogenic global warming. In other words, it’s your fault, so please do pay attention.
Weather patterns tend to move latitudinally across the globe. You’ll get a period of no rain or snow for a while punctuated by precipitation, then the precipitation moves on and it is dry again for a while. The typical pattern of dry and precipitation in a given region changes by season, but if you compare one season to the next over several years there is normally a pattern. In some areas it is mostly wet with some dry, other areas mostly dry with some wet, other areas somewhere in between. The same can be said of cold vs. warm air masses.
Here in Minnesota, May and June tend to have repeated intense storm fronts moving through every few days for a few weeks, though the exact timing of when this stormy weather starts and ends, and how long it lasts, varies. Also, the nature of the storms varies, with some years having many tornadoes, some years having mostly straight line winds, etc. Meanwhile, in Minnesota, I get the impression that August is usually relatively dry and cool. Many Minnesotans who have cabins way up north regard August as the first month of fall, that’s how cool it is. Where you live there is a pattern, and you’ve probably noticed it.
Weather whiplash is when this happens: Instead of periods of dry and wet alternating as they normally do, one of those two patterns (dry or wet) gets stuck in place for a period of time. I get the impression that dry periods, when they get stuck, get stuck for many days in a row, while wet periods get stuck for less time. The reason for that may be this: The dry air masses that get stuck are larger because high pressure systems are big and tend to be dry, while wet weather systems are smaller. So, if all the weather got stuck all at once in the northern temperate region, more landscape would be under dry, clear skies and less landscape would be under wet, cloudy skies.
And of course, a gentle fluctuation back and forth between warmer and colder conditions is replaced, under weather whiplash conditions, with long periods of cooler or long periods of warmer weather.
Here’s the problem. If the weather is warm-cool-warm-cool over a periods of two weeks, it never gets that warm or cool. But if it is just warm-warm-warm-warm over a period of two weeks, that’s a heat wave. The heat builds and it gets warmer and warmer and warmer until it is just plain stinking hot. Or, conversely, if the weather is cool-cool-cool-cool and that happens mid winter, that’s a cold snap. Or, like happened this year in Minnesota, it can get cool-cool-cool-cool just at the time we should be having some spring rains, so instead we get spring snows for a month. Residents of the Twin Cities feel the pain of this even now, because the entire construction season (we have two season here, “Winter” and “Construction”) was delayed by a month due to weather whiplash, and the Minnesota Department of Public Works and county and local DPW’s have been working extra hard at ruining our commute today so that our commute can be better at some unspecified time in the future, right after the pigs start flying.
If the weather patterns sit in one place for a long time and cold or heat or dry or rain builds up … so you get a cold snap, heat wave, drought, or floods … then one part of weather whiplash is in effect. Then, the weather shifts and where there was once hot and dry, and thus maybe fires that denude the landscape, you have floods, made worse not only because of the stalled system but also because the fires prepped the grounds for greater runoff, erosion, and land slides. That’s the full weather whiplash pattern. Seemingly interminable weather of one kind suddenly replaced by seemingly interminable weather of another, perhaps opposite kind. Snap.
Farmers have to put their crops in late because of a long period of cool and wet conditions. Then the weather clears and everything is nice and dry, so the farmers plant later than ideal, but at least they get to plant. But then the nice and dry conditions are like the proverbial TV in-laws and never seem to want to leave, and good planting conditions turn into a worrying period of not enough rain and that turns into a moderate drought, and that turns into a severe drought. Then, just as you are about to harvest the half dead corn and maybe use it for halloween decorations because it is not good for anything else, the weather whiplashes on you again and your half dead crops are mowed down by a series of hail storms. This is not good for farmers.
Weather whiplash does seem to be a recent phenomenon, even if stalled systems can actually happen at any time. I think this is true because people like Paul Douglas seem to think it is true, people who have been watching the weather every day for years. It is hard to find a simple comprehensive set of data that demonstrates this, however. One way to look at this is to examine the frequency of “natural disasters” of various types over time, according to the people who know most about such things: the insurance industry. Following is a graph just for the US. I assume that weather whiplash is a global Northern Hemisphere phenomenon (maybe also Southern Hemisphere, but for various reasons maybe not; see below). I also assume that while the United States, being fairly large, is thus a good sample of the Northern Hemisphere, weather whiplash might be happening more in Eurasia one year and more in the US another year. However, there is reason to believe that that would not be the case to any large degree because the jet stream waviness is a global thing. Anyway, here’s a data set in the form of a chart from the insurance industry showing natural disasters in the US from 1980 to 2011. It is from this document (PDF).
Clearly there is an increase in the overall number of disasters. Climatological events including extreme temperature, drought, and forest fires increase across the time period of consideration. Floods and mass movement of water also clearly increases across this time period. Storms also increase. Geophysical events on the other hand, don’t. This is, of course, what we would expect if weather related events were having more of an impact. Is this weather whiplash?
One could argue that global warming would increase extreme temperature conditions and drought without anything special like weather whiplash happening. Also, global warming can increase rain and flood related problems because warmer air and seas means more evaporation. And, certainly, that is what has occurred over time.
And this is a very important point that I keep telling people but I’m not sure how well it has gotten across. Adding heat to the atmosphere may add moisture, and it may add drying conditions as well. It might increase storminess, or the intensity of some storms. But that is just a quantitative change in the weather, caused by global warming, and while important it is still a simple matter of degree.
Weather whiplash is not a quantitative change in weather patterns. It is not just a bit more rain or a bit more heat in what might otherwise be a rainy day or a hot day. Weather whiplash is a qualitative change in the patterns of weather. Qualitative, large scale features of climate (and weather) give us things like desserts and rain forests. They give us seasonal patterns. They give us expectations of a wet spring that gets dry enough to plant, enough rain falling in small enough bouts to keep the crops growing over the summer, and a reasonably dry fall so the harvesting machinery can get out in the fields and bring in the sheaves. Or, if there is a qualitative shift in the climate and weather, like weather whiplash becoming a common phenomenon, it might be that you can’t really grow corn where you were thinking you could, or if so, you need a different approach. And since all we eat and grow is corn, we are in big trouble. It might mean that the idea of living in excessively quaint villages next to medium size creeks in very large mountains is simply not an option any more, because “1,000 year floods” can happen any time if weather whiplash happens to aim its cruel cat-o-nine-tails at your quaintness.
The qualitatively distinct phenomenon of weather whiplash … the multi-day or even multi-week long stalling of weather patterns … builds on incremental increases in dryness of air (due to heat) and increased wetness of other air (due to increased evaporation) and increased storms (due to increased energy in the atmosphere) and make all that worse.
Imagine you have the habit of tossing the daily accumulation of spare change that forms in your pockets in random locations around your house at the end of each day. Then, something changes in your pattern of behavior and you end up coming home with more change every day (the price of something you frequently buy goes from 95 cents to $1.05, and you only pay with dollar bills). You still toss the change randomly, but now there is somewhat more spare change on your nightstand, on the table by the front door, in that basket on the desk in your study, in the laundry room. That’s a quantitative increase in spare change due to a change in the nature of making change during the day. It could matter, you might notice it, it may suddenly become worth it for the teenager in your household to volunteer to help clean the house if they can keep all the change. But it is just a matter of degree.
But what if you ALSO change what you do with the change. Instead of randomly dropping the change in a large number of locations, you change your pattern and most of the time you empty most of the change from most of your pockets into the single basket on your desk in the study. In short order you would have a lot of change in one place not only because you are accumulating more every day but also, and really, mainly, because you are putting it all in one place. Soon there would be many dollars worth of quarters, dimes, nickels and pennies in your basket, enough to take to the bank. Now, THAT’s change we can believe in!
Weather whiplash on top of increased moisture in the air brought us drought and fire followed by unprecedented rainfall in Colorado just a couple of weeks ago. It flooded Central Europe and Calgary, Alberta. It brought killer cold and heat waves to Eurasia and North America over the last couple of years. It blocked Hurricane Super-Franken-Storm Sandy and steered it into New York and New Jersey about a year ago. It brought a “Flash Drought” to the US midwest this summer. And so on and so forth.
That, dear reader, is change we better believe in.
OK, but how does weather whiplash happen? I’ve explained this before (here) but I’ll give you a quick run down now in case you are to lazy to click on that link.
There are mysterious processes at work. They are not mysterious to climate scientists who can do calculus, of course, but they are a little hard to explain in a straight forward process without using analogies that ultimately break down. But I’l use a couple of analogies anyway. Feel free to complain about them in the comments, or offer better ones!
First, this: Climate is all about excess heat moving from the equatorial regions to the poles. When it does so across the troposphere, big-giant patterns of air movement are set up. These patterns can be thought of as giant twisting donuts of air encircling the earth (though that is only a rough description, on a simpler planet it would be very accurate). Air at the equator rises, moves away from the equator and cools, then sink, and works its way back towards the equator. Then, the next donut in line does same thing but twisting in a different direction. And so on. In cross section, it looks like this:
The junctions between these giant twisting donuts, at altitude, are the jet streams.
Weather generally moves along and within these donuts, nudged along and otherwise affected by the jet streams, in the manner described at the beginning of this post. Dry-wet-dry-wet or cool-warm-cool-warm, at the scale of days. Or, should I say, this regular pattern of normal variation happens as long as the jet streams are straight and all normal and stuff.
Here’s a depiction of the jet streams being fairly normal (from here):
But it does not always work that way. Visualize a straight river with a flat gravel bottom moving along at a reasonable clip in front of you. Observe the hibiscus flowers released by plants upstream (as happens in some tropical rivers) floating by each in a regular linear pattern. The river is a giant twisting donut, the hibiscus flowers are weather events. Now, drop a big log halfway across the river so one end is on the bank, and the other end is out in the middle of the river and pointing slightly upstream. Now, the water is partly trapped, and forms a vortex upstream from the log, and also, a vortex going perhaps in the opposite direction forms downstream from the log. The hibiscus flowers trapped in the vortex now fail to float by, but rather, spin and spin and spin and remain in the same place. Dozens of these flowers might get trapped in place, and beneath the surface, even the gravel is starting to mound up under parts of the stream that are moving slower, and dug out in other parts. Where that vortex occurs, above the log, will be many hibiscus flowers, or, rain storms, over a period of time. Perhaps below the log there will then be a paucity of hibiscus flowers, or, drought, for a period of time. Eventually the log gets lose, rolls downstream a ways, and gets stuck again. Then, some other part of the river … some other region … gets to experience the stuck vortex.
When the gradient in heat between the tropics and the poles is at a certain level, you get a nice straight jet stream most of the time. When the gradient drops, for complex reasons involving calculus and such, the whole donut-jet stream thing gets all messed up like the river with the log dropped across it, and the jet streams fold up in to these big curves called “Rossby waves.”
Over the recent years, we have experienced general global warming, and this has caused the sea ice that covers much of the Arctic Sea to melt more in the summer than it usually does. This has caused the whole northern region to become warmer because there is less reflective ice and more open ocean to collect sunlight. This has caused even more melting of the ice, and over the last decade we’ve seen a catastrophic reduction in sumer arctic ice that, while it was expected that this would happen over time, has occurred at a shocking rate of speed that has kinda freaked everybody out. This warming of the Arctic in relation to everywhere else is called “Arctic Amplification.” Arctic amplification has caused the differential of equatorial vs. polar temperature to shift, and this has caused the Rossby waves to form.
The waves themselves don’t move at all or move only very slowly for several days, and form vortex patterns to their north (which are low pressure systems) and to their south (which are high pressure systems). The air moving along the jet stream itself also slows down. So, any wether pattern that might just float by like a hibiscus flower on a tropical river instead sits here and either rains on you for a week or shines bright sun on you for a week, or whatever. Then, the waves move or disappear and reform elsewhere, like the log getting lose and rolling down stream for a ways, and the place that was for several days dry is now for several days wet.
So, is there any evidence that weather whiplash has been happening more frequently in recent years other than so many meteorologists simply claiming it has?
I asked a number of colleagues who work with climate and weather if there was a readily available database showing jet stream waviness and big storm events that could be converted into a human-understandable picture, or graph, or something, of this change over time. I had already read two recent papers that looked at this phenomenon but they are highly technical and on their own don’t have graphics that do the job. So, I asked one of the authors of one of those papers about a quick little trick (OMG HE USED THE WORD TRICK IN RELATION TO CLIMATE) to convert one of their more complicate graphs into something more obvious. Below, I provide you with the original graphic and the one I generated from it. This shows the frequency over time in a limited size study area (not the whole Northern Hemisphere) of conditions under which Rossby waves would cause weather whiplash conditions. Remember, this is just a sample of the planet in both time and space, not the actual number of times this happens. But, the sampling is uniform over several decades, so if there is an increasing trend of jet-stream curviness at the level that could cause wether whiplash, it will be shown, more or less, here. The numbers are so small that I don’t even attempt a test of significance. This is provisional. Suggesting. For fun. If one can call the outcome of weather whiplash fun, which you really cant. Anyway, check out these two items:
…and, from this figure, I created the following graphic, counting the number of QR events (the squares) per unit time evenly divided across the sampling period:
Here’s the thing. We can’t easily say that there is a qualitatively new climate system in place, because by definition “climate” is what happens over 30 years of time. There is no “new climate” that is five or ten years old. That, however, is not because of a natural process. It is because of how climate science has evolved. It makes sense for climate scientists to think in multi-decade chunks of time because climate really does vary at levels less than 20 or 30 years time, normally. Taking a normal climate science perspective, we can be pretty sure that “weather warming” is a new climate regime some time around the middle of the 21st century when there is enough data!
But this is a problem. If the situation is changing rapidly enough it will be hard for methods that have evolved in climatology to respond to, or even, really, “see” it. Trying to understand weather whiplash by long term study of the climate system is a bit like using the publicly available long term FBI crime stats that were last updated two years ago to assess whether or not your house is being broken into right now.
As you know, the IPCC report on the scientific evidence related to climate change is coming out just now. That report is not so sure about changes in weather severity or storminess or stuff like weather whiplash. Some weather changes are acknolwedged as very likely, others, the IPCC report is much more equivocal about. However, there are very few people in climate science right now that don’t think something like weather whiplash is probably happening, and many are well convinced of it. The problem is that the IPCC reporting process is more like climate than weather in its temporal scale!
The IPCC reporting process has a time lag of several years; the final, most policy related report for this cycle will be out in some 12 months from now, a year after the first report in the cycle, the one with the science in it. In a few years from now, and not likely before, there will be important people sitting in important room in important buildings talking about climate. Someone will say “is drought a thing?” and someone else will say “IPCC says they are only moderately sure at best that drought is a thing.” It won’t matter that the conversation is happening in July 2015 and the last piece of data in the IPCC report is from 2011 and drought has been a dominant result of weather whiplash for five years … enough time to overlap with but not influence the IPCC conclusions.
Weather whiplash is almost certainly for real.
Finally, here are two videos that also go into this topic. From the Yale Climate Forum, “New video couples interviews with two experts — Rutgers’ Jennifer Francis and Weather Underground’s Jeff Masters — to explore the ‘Why?’ of two years of mirror images of weather across North America”
…and “”Wummer.” Just days ago, it looked and felt like winter in many cities across the the Midwest. Then whammo, it’s summer with record breaking heat across several Midwest states. Yes, double digit snowfalls to triple digit heat all within a matter of days. Meteorologist Paul Douglas says this takes Weather Whiplash to a whole new level.”
There is a strong argument to be made that the recent flooding in Colorado is the result of global warming. Here are three things one could say about the flooding. Think of these as alternative hypotheses to explain that event:
1) Weather has extremes. Sometimes, instead of raining just a bit, it rains a hella lot and you get a big giant flood.
2) Weather has extremes etc. etc. but global warming tends to make some of the extremes more extremes, so instead of getting just a big flood, you get a big giant flood.
3) The storm that brought well over a foot of rain to one mountainous area was qualitatively distinct; it happened because of a configuration in the weather patterns that might have happened at any time over the last several centuries but only very very rarely, but because of global warming, this sort of thing happens far more frequently. The weather patterns in the Northern Hemisphere have shifted in a way that makes the rain event in Colorado a fairly likely thing to happen somewhere in the world several times a year, and it happened to happen in Colorado this time around. Prior to global warming caused changes, this effect would be very rare, now it is common.
The difference between these ways of looking at the weather is very important, because under option 3, we have a problem. Just as people who live along the Gulf Coast or the mid-Atlantic or south need to worry about hurricanes as a thing, or people who live in the middle of the US have to worry about tornadoes as a thing, or people who live in Minnesota have to worry about killer cold as a thing, it may be the case that people who live at latitudes in the Northern Hemisphere now have to worry about this new weather pattern, which some call “weather whiplash,” as a thing. When you build your mountain roads in the Rockies, you’ve got to figure that there is a reasonable chance that during the next few decades there will be a foot of rain in the catchment of the stream that road runs along. Either build the road differently, or plan to replace it now and then. Mountain valley settlements in high mountains like the Rockies may need to measure out a new “high water line” for the creek they overlook and plan for that water line being reached within the lifetime of the inhabitants of the village, once or more.
Similarly, just as dense concentrations of rain are more likely under option 3, dense concentrations of dry conditions are also likely. In other words, weather whiplash is like my old broken sprinkler.
Until recently I had one of those sprinklers that wave back and forth with a couple dozen high power streams of water. The water comes out of a bar, and the bar oscillates back and forth and back and forth so there is a long, linear, gentle rain storm that passes back and forth across the lawn over the zone covered by the sprinkler. But when my sprinkler got old it would get stuck sometimes. The bar would stop oscillating, and the streams of water would create a long linear rain storm on one strip of the law while the rest of the lawn simply got dryer. The broken sprinkler did something that resembles the weather in the middle-ish part of the United States for a week or so during September 2013. The midwest got a “flash drought” during which no rain fell but it as hot and breezy, while the Rockies and other areas got lots of rain from a big storm that sat there for days and days without moving. The main part of the storm was in Colorado but New Mexico got extra rain as well, and after the storm left Colorado it moved north in the Rockies and wet down Wyoming and Montana a bit as well (causing only some flooding).
The jet stream is often a long, linear, fast moving necklace (well, more than one necklace as there is more than one jet stream) that encircles the earth at some distance from the equator. It is associated with the movement of air masses around the globe. These air masses alternately pick up and drop moisture. When the air mass is dry, it dries out the land beneath. When the air mass is wet, and it mixes with some other air along a front, it drops rain. But the rainfall (and correspondingly, the dry spots) are somewhat like an oscillating sprinkler that is not broken. A given area is likely to experience alternating rain and dry.
Some regions experience more dry than wet, some regions are wetter, but the rainfall across a given region is typically doled out in chunks, some of which can be very heavy, but rarely more than a few inches in a given storm.
Lately, the jet stream seems to have been very frequently changing its configuration. Instead of being a relatively straight circle around the globe it is all kinked up in the big “waves.” Where there are waves, several things happen. First, the movement of air along the jet stream slows down, and this interacts with other air masses. More importantly, it seems, is that the kinks create large very slow moving or stationary low and high pressure systems. The high pressure systems are south of the jet stream, the low pressure systems are north of it, but since the jet stream is kinked, these low and high pressure systems end up being next to each other. So, we get tropical stuff moving north, and subarctic stuff moving south, and there are vast differences in moisture and temperature. This can result in two things at the same time. Some regions have dry conditions and some have lots of precipitation. The key thing is this: Since these systems are very slow moving, or sometimes, just plain stuck, like my sprinkler, the dry conditions persist for many days, and the wet conditions persist for many days. Thus, Colorado.
I wonder if is possible that the position of the waves in the jet stream will end up being more frequently located in certain spots. I have no reason to say this empirically, but since air mass movement is linked to the position of mountains and oceans and stuff, it seems a reasonable question to ask. If that ends up being the case, than we could end up with a new climate regime wherein certain areas tend to get repeated stalled rain systems (not every year, but just more frequently than average) while other regions get repeated stalled dry conditions. That might be good news, because it might be easier to adjust to weather whiplash with more predictability. But if this sort of pattern was to be strong, we would probably see it already, so don’t count on it. Most likely, a climate pattern where very rainy weather shows up out of nowhere and sits on top of you for a week while elsewhere dry conditions persist for a few weeks in a row is not good for agriculture or for mountain villages and roads.
I got a new sprinkler. It wasn’t easy. This time of year it is hard to get sprinklers because they tend to stock up on them in the spring. Also, with the drought conditions were’ve been experiencing over the last few weeks in my neighborhood, there has been a run on the few sprinklers that are left. Climate change made it hard for me to find a sprinkler! (First World Problem #212124). But eventually I got one. I’m not sure how hard it will be to get a new climate.
Global Warming is the increase in the Earth’s temperature owing to the greenhouse effects of the release of CO2 and other gasses into the atmosphere, mainly by humans burning fossil fuel, but also by the release of Methane from oil wells and melting of Arctic permafrost, natural gas from leaky pipes, and so on. This increase in temperature occurs in both the atmosphere and the oceans, as well as the land surface itself. During some periods of time most of the increase seems to happen in the atmosphere, while during other times it seems to occur more in the oceans. (As an aside: when you use passive geothermal technology to heat and cool your home, the heat in the ground around your house is actually from the sun warming the Earth’s surface.)
“Weather” as we generally think of it consists partly of storms, perturbations in the atmosphere, and we would expect more of at least some kinds of storms, or more severe ones, if the atmosphere has more energy, which it does because of global warming. But “weather” is also temperature, and we recognize that severe heat waves and cold waves, long periods of heavy flooding rains, and droughts are very important, and it is hard to miss the fact that these phenomena have been occurring with increasing frequency in recent years.
We know that global warming changes the way air currents in the atmosphere work, and we know that atmospheric air currents can determine both the distribution and severity of storms and the occurrence of long periods of extreme heat or cold and wet or dry. One of the ways this seems to happen is what is known as “high amplitude waves” in the jet stream. One of the Northern Hemisphere Jet Streams, which emerges as the boundary between temperate air masses and polar air masses, is a fast moving high altitude stream of air. There is a large difference in temperature of the Troposphere north and south of any Jet Stream, and it can be thought of as the boundary between cooler and warmer conditions. Often, the northern Jet Stream encircles the planet as a more or less circular stream of fast moving air, moving in a straight line around the globe. However, under certain conditions the Jet Stream can be wavy, curving north then south then north and so on around the planet. These waves can themselves be either stationary (not moving around the planet) or they can move from west to east. A “high amplitude” Jet Stream is a wavy jet stream, and the waves can be very dramatic. When the jet stream is wavy and the waves themselves are relatively stationary, the curves are said to be “blocking” … meaning that they are keeping masses of either cold (to the north) or warm (to the south) air in place. Also, the turning points of the waves set up large rotating systems of circulation that can control the formation of storms.
So, a major heat wave in a given region can be caused by the northern Jet Stream being both wavy (high amplitude) with a big wave curving north across the region, bringing very warm air with it, at the same time the Jet Stream’s waves are relatively stationary, causing that lobe of southerly warm air to stay in place for many days. Conversely, a lobe of cool air from the north can be spread across a region and kept in place for a while.
Here is a cross section of the Jet Streams in the Norther Hemisphere showing their relationship with major circulating air masses:
Here is a cartoon of the Earth showing jet streams moving around the planet:
Here is a depiction of the Jet Stream being very curvy. The waves in the Jet Stream are called Rossby waves.
(See also this animation on Wikicommons, which will open in a new window.)
Research published in the Proceedings of the National Academies of Science last February, in a paper titled “Quasiresonant amplification of planetary waves and recent Northern Hemisphere weather extremes,” links global warming to the setup of high amplitude waves in the Jet Stream, as well as relatively stationary, blocking, waves that cause extreme warm or cold conditions to persist for weeks rather than just a few days. According to lead author Vladimir Petoukhov, “An important part of the global air motion in the mid-latitudes of the Earth normally takes the form of waves wandering around the planet, oscillating between the tropical and the Arctic regions. So when they swing up, these waves suck warm air from the tropics to Europe, Russia, or the US, and when they swing down, they do the same thing with cold air from the Arctic…What we found is that during several recent extreme weather events these planetary waves almost freeze in their tracks for weeks. So instead of bringing in cool air after having brought warm air in before, the heat just stays.”
So how does global warming cause the northern Jet Stream to become wavy, with those waves being relatively stationary? It’s complicated. One way to think about it is to observe waves elsewhere in day to day life. On the highway, if there is enough traffic, waves of cars form, as clusters of several cars moving together with relatively few cars to be found in the gaps between these clusters. Change the number of cars, or the speed limit, or other factors, and you may see the size and distribution of these clusters (waves) of cars change as well. If you run the water from your sink faucet at just the right rate, you can see waves moving up and down on the stream of water. If you adjust the flow of water the size and behavior of these “standing waves” changes. In a baseball or football field, when people do “the wave” their hand motions collectively form a wave of silliness that moves around the park, and the width and speed of that wave is a function of how quickly individuals react to their fellow sports fan’s waving activity. Waves form in a medium (of cars, water molecules, people, etc.) following a number of physical principles that determine the size, shape, speed, and stability of the waves.
The authors of this paper use math that is far beyond the scope of a mere blog post to link together all the relevant atmospheric factors and the shape of the northern Jet Stream. They found that when the effects of Global Warming are added in, the Jet Stream becomes less linear, and the deep meanders (sometimes called Rossby waves) that are set up tend to occur with a certain frequency (6, 7, or 8 major waves encircling the planet) and that these waves tend to not move for many days once they get going. They tested their mathematical model using actual weather data over a period of 32 years and found a good fit between atmospheric conditions, predicted wave patterns, and actual observed wave patterns.
The northern Jet Stream originates as a function of the gradient of heat from the Equatorial regions to the Polar regions. If air temperature was very high at the equator and very low at the poles, the Jet Stream would look one way. If air temperatures were (and this is impossible) the same at the Equator and the poles, there would probably be no Jet Stream at all. At various different plausible gradients of temperature from Equator to the poles, various different possible configurations of Jet Streams emerge.
One of the major effects of global warming has been the warming of the Arctic. This happens for at least two reasons. First, the atmosphere and oceans are simply warmer, so everything gets warmer. In addition, these warmer conditions cause the melting of Arctic ice to be much more extreme each summer, so that there is more exposed water in the Arctic Ocean, for a longer period of time. This means that less sunlight is reflected directly back into space (because there is less shiny ice) and the surface of the ice-free northern sea absorbs sunlight and converts it into heat. For these reasons, the Arctic region is warming at a higher rate than other regions farther to the south in the Northern Hemisphere. This, in turn, makes for a reduced gradient in the atmospheric temperature from tropical to temperate to polar regions.
Changing the gradient of the atmospheric temperature in a north-south axis is like adjusting the rate of water flowing from your faucet, or changing the number of cars on the highway, or replacing all the usual sports fans at the stadium with stoned people with arthritis. The nature of the waves changes.
This video shows how Donald Trump and Bill O’Reilly are like global warming.
In the case of the atmosphere of Earth’s Northern Hemisphere, global warming has changed the dynamic of the northern Jet Stream, and this has resulted in changes in weather extremes. This would apply to heat waves, cold snaps, and the distribution of precipitation. The phenomenon that is increasingly being called “Weather Whiplash” … more extremes in all directions, heat vs cold and wet vs. dry, is largely caused by this effect, it would seem.
This study is somewhat limited because it covers only a 32 year period, but the findings of the study are in accord with expectations based on what we know about how the Earth’s climate system works, and the modeling matches empirical reality quite well.
Petoukhov, V., Rahmstorf, S., Petri, S., & Schellnhuber, H. (2013). Quasiresonant amplification of planetary waves and recent Northern Hemisphere weather extremes Proceedings of the National Academy of Sciences, 110 (14), 5336-5341 DOI: 10.1073/pnas.1222000110
I think most people will agree that in North America (and other places) we’ve been having some bad weather. Some of the weather is not necessarily intrinsically bad … so what if it is a little cooler or a little warmer than you expect. Aridity? Deserts are nice! Extra rainfall? Great for the plants. But actually that sort of thing has its down side since important systems like agriculture, the water supply, and Spring Break work reasonably well because of expectations that might not be met if the weather is different.
Other weather is intrinsically bad. I’d mention tornadoes but at the moment climate and weather experts are not at all agreed on whether or not we are having more, worse, bigger, or otherwise badder tornadoes and if there are differences in tornadoes this decade compared to earlier decades, why that is the case. But other things can be pointed to. Superstorm Hurricane Sandy was the hurricane that should not have gone where it went, should not have been so strong, perhaps should not have been at all. Droughts. Widespread wildfires caused by droughts. Lots and lots and lots of rain causing widespread flooding. Heat waves and cold waves. As a category of things that can happen, these things are in the “bad weather” category, and it is reasonable to ask why they are happening so much “these days.”
It is possible that these changes in weather, or more exactly, these examples of rapidly changing weather that have come to be known as “Weather Whiplash,” are caused by global warming which in turn is caused by the unchecked release of large amounts of fossilized carbon into the atmosphere with the burning, by humans, of fossil fuels. But before I get to that argument (short answer: Weather Whiplash is caused by global warming, but hold on just a sec..) I want to point something else out that is very important.
I want to point out the problem of understanding shifting conditions. Let’s say you are a storekeeper and every day you make a certain amount of profit. How much you make each day varies a great deal owing to a large number of factors. I knew a guy who worked in a camera shop just off Wall Street. He would sell no cameras for days on end and then suddenly sell a gazillion cameras. That would be on a day that the stock market went way up and traders felt flush, and went and bought the expensive cameras and lenses they had been coveting for weeks. I know people who had businesses on Cape Cod and how much money they made on a given weekend depended on the weather forecast for “The Cape” shown to Boston area audiences on Friday (regardless of the actual weather itself, generally). But underlying all this is another set of factors that do not vary day to day or hour to hour (or week to week or even seasonally). One is the overall long term state of the economy (how much stuff do people buy, based on how free they feel with their cash). Another is the overall demand for your particular goods, which may vary little if you sell food but a lot if you sell some trendy widget.
In the absence of good information, how do you know if your business is about to either tank, because people stopped buying your goods, or take off, because people can’t get enough of your goods? If your sales shift a great deal in one day, is that enough information? No. If your sales shift for an entire week, does that tell you something? Maybe, probably not. Most likely, you can identify normal pseudo-cycles, ups and downs, that occur in your business and estimate their length. Some factors cause your business to go up and down over scales of weeks, some over scales of days. Perhaps you can estimate that if you get an average amount of business over six months, and that is higher or lower than the previous six months, then you can say that a basic shift has happened.
Weather has cycles and pseudo-cycles just like businesses do, and they run over the course of days, seasons, years, and somewhat longer cycles that have to do with the position and relationships of major high pressure systems that shift around over cycles of five to fifteen years, and a few other thigns.
Now think about what we expect from global warming.
A simple yet usable model is this: More CO2 in the atmosphere = more heat (energy) in the atmosphere = climate change. But the expected climate change is not linear. Models that seem to work together with direct observation show us that more CO2 has resulted in aridity and wildfires in certain areas. But if we go back in time to when there was even more CO2 in the atmosphere, it seems like everything was wetter, so the whole drought and wildfire thing may be something that gets worse and worse through the 21st century, but at some point is replaced by a whole different set of problems. With respect to sea level rise, which I think is one of the biggest problems we face, it is not likely that the continental glaciers will melt steadily. Most likely they will melt, once their melting really gets going, both steadily and in fits and starts, causing the occasional large rise in sea level.
In other ways, the climate system is likely to change rapidly from one state to another. We are seeing the melting of Arctic Sea Ice each year doing this now, going from one system where there was melting and re-freezing at a certain rate, and changing to a completely different system. Along with this we may be seeing a fundamental long term shift in the nature of Arctic air masses from one way of being to another.
It is like making ice cream, or butter, shaking catchup out of a bottle, or going steady. You work on it and work on it and work on it and all you have is cream and ice, or cream in the churn, or catchup stuck in the bottle, or a friend. Then, suddenly, you have ice cream, or butter, catchup spewing out all over the place, and a significant other. There are many things in life that work this way, where there is not a steady change over long periods of time, but rather, a lot of one thing followed by a sudden shift to a whole different kind of other thing.
So, here’s the problem. If cycles of normal climate change are in the order of a dozen years, but a particular true shift in the basic pattern of climate takes, say, five years and thereafter everything is different, how do you know it happened? How do you know that the “new normal” is a long term change rather than a temporary shift?
There are two ways to know this. One is to wait and see, but if you were thinking of doing something about it but only taking action after you are sure, this is foolish. The other is to use reason and science and stuff to figure out what is going on and then make your best estimate of the situation.
And this brings us back to Weather Whiplash, the New Normal, and the nature of the climate change we may very well be experiencing now. There is an explanation for Superstorm Hurricane Sandy, for Nemo and some of the other storms we’ve had over the last year or so, and for the strange spring and early summer we are experiencing now, and please don’t forget, the strange winters and summers we’ve been having for the last few years. This explanation applies mainly to the Northern Hemisphere and has to do with the Arctic and the Polar Jet Stream.
The Earth’s climate operates as a mechanism for moving excess heat form equatorial regions towards the poles in air and oceanic currents. In the atmosphere, part of this happens when warm tropical air rises and moves away from the equator, drops, and then flows back towards the equator. Farther from the equator, a separate cycling of air currents is thus set up, where air moves up then south at altitude, then drops along side that first cycle of air. Then, there is a third similar giant rotating donut of air closer to the poles. At those positions where the air is moving up, there tend to form high pressure systems, and where the air flows away from these high pressure ridges or mounds, low pressure systems develop. If you stand back and look at the Earth from a distance you can see bands of wet and bands of dry, and regions where certain kinds of storms (like hurricanes, for example) tend to be confined.
The jet streams form at the boundaries between these large scale systems, at altitude, near the top of the troposphere. The jet streams don’t really shape the larger scale systems; rather, they exist because the larger scale systems exist. But once they are in place, the jet streams can determine what happens in those systems.
One of the major jet streams is the Polar Jet Stream that separates temperate regions form more arctic regions. This boundary between two major air masses, defined by that jet stream, can be thought of as analogous to the partition that separates the freezer compartment in the top of a typical refrigerator from the fridge part down below. With this partition in place, the stuff in the freezer stays very cold, and the stuff in the refrigerator stays less cold. If you kept all the cooling coils in place but removed that partition, the difference between the freezer and refrigerator compartments of your Frigidair would be reduced significantly.
Another thing the Polar Jet Stream does is to generate the overall shape of the boundary between temperate and more northerly air masses. The jet stream can be straight, like a big ring around the earth, or it can be all wavy, with major undulations north and south. In the latter case, these undulations can move around the planet or they can sit in place. When they sit in place, they may cause an entire region to be habitually wet, or dry, or more importantly cool or warm, for a long period of time. (This is called “blocking.”) The shape and movement pattern of the Polar Jet Stream ultimately determines the overall pattern of weather everywhere in temperate and subarctic regions.
Now, remember that the position and shape, and movement pattern, of the Polar Jet Stream is determined by high pressure ridges and the low pressure systems they set up (more accurately, these things interact). High pressure systems are relative; A warmish region of the earth, warm relative to nearby cooler regions, will set up a high pressure system. So, during the summer, land masses tend to create high pressure relative to nearby oceans, but during the winter, the oceans may create stronger high pressure relative to land.
And at this point we can see how climate change caused by CO2 increases create Weather Whiplash and other effects.
Warming conditions have caused the Arctic sea to have much less sea ice on it for much longer periods of the summer. This, in turn, allows more sunlight to heat the arctic, because less sunlight is reflected away by shiny ice, and more sunlight provides heat to the sunlight absorbing open water. This changes the relationship between high and low pressure areas in the Northern Hemisphere. This, in turn, has caused the Polar Jet Stream to freak out. Sometimes it is very wavy, often it is blocked, and sometimes it is simply weakened to the point that it almost goes away and allows the freezer and refrigerator compartments to meld.
Cool weather in the United States is not really cool wether. It is the more even, less compartmentalized, distribution of heat across the region north to south. Everything is on average warmer (because of warming) but there is not a very stark boundary between the northern colder regions and the more southerly warmer regions. Last April when we were busy getting snowed on every few days in Minnesota, the Arctic was warmer (but still cold) than it normally would be. Last fall, the shape of these weather systems caused Superstorm Hurricane Sandy to be stronger, and to fail to do what these storms normally do: head north by northeast and dissipate. Instead, the storm turned left and blotto’ed New York, Connecticut and New Jersey.
Peter Sinclair of Climate Denial Crock of the Week, famous for his videos, in a post on Weather Whiplash, has produced a video that covers some of this very nicely:
So, lets get back to the original question. Why are we having such bad weather? Because the system that is usually in place, with a strong Polar Jet Stream that tends to be linear during the summer, has changed to a different system where the Arctic Oscillation … a high-low pressure system pattern … has shifted to a “negative” configuration because of warming of the Arctic sea. This different system has a number of effects that combine with other effects of global warming to produce strange weather. Those other effects include there being more energy in the atmosphere, and more moisture concentrated in more discrete dense patches, which therefore also means some very dry conditions. Blocking may have caused dry conditions to persist longer over selected areas than otherwise, and at the moment, blocking and added moisture seems to be causing the midsection of the United States to become the world’s largest water park. And, between storm fronts, the overall weather of the region is cool, yet the storm systems are very energetic.
Weather Whiplash. It makes sense because everything that is happening conforms to expectations based on what we know about climate and weather. Will this really be the “new normal?” Is a few years in a row of a strange acting Polar Jet Stream and that other stuff the result of a fundamental change in the way our climate system works, or is it just a typical variation that we can expect to happen now and then. Well, if this was a typical variation of the type we normally see on occasion, there would be less incredulity among climatologists, meteorologists, and forecasters. It makes more sense to explain Weather Whiplash as a new state that the climate has shifted to (mostly, expect some more back and forth, I assume) because of the unchecked release of fossil Carbon into the atmosphere by the burning of fossil fuels by humans.
I’d like to give you a very small selection of references and discussions about the link between global warming and drought.
Global warming probably has two major effects. First, more moisture gets into the atmosphere because warmer air passing over the oceans can take in more water. This can cause more rain and possibly more severe storms and flooding. But the atmospheric system also changes in another way. The hydraulic cycle, as it is called, intensified in both directions, wet and dry. If you live on the East Coast of the US and you move to where I live in the upper Midwest, you’ll get a special appreciation of this. Rain on the East Coast comes in thunderstorms now and then, but a lot of the rain comes from big wet air masses linked to the ocean. In Boston it can rain for a few days off and on but mostly on, with an inch off rain falling over a long period of time. But here in the Midwest, that almost never happens. Instead, it’s not raining, then this big scary storm comes and dumps a whole pile of rain on you, then it moves on. In between storms it can be dry vor many days. The Midwestern storms come from warm air masses passing over the Gulf of Mexico and moving north (then turning “right” at some point) with contributions from elsewhere. It is more intensified hydrological system, with a lot of variation. That is a min-model (albeit a pretty inexact one) for shifting to a warmer planet. Keep in mind that between rain storms, warmer air takes moisture out of the local system (to dump it in a storm somewhere else). Climate experts generally agree that a warmer world will have more severe storms, though which storms will be more severe and in what way is not clear, and drought. Lots of that. Continue reading What is the link between global warming and drought?→