A new voice has taken center stage in the argument over what to do, if anything, about man-made climate change.
Although clear for decades, the science is easily obscured by clever propogandists. But thanks to this new advocate, things have changed; hers is a voice powerful enough that we’re nearing the point where climate deniers simply won’t be taken seriously any more. An unimpeachable source, impervious to politics, we cannot help but listen, by the millions, from New York to California, from Alaska to Florida, women and men, liberal and conservative and independent, Christian and Jew and Moslem and atheist alike.
The children hear her loudest.
Nature has been telling us for decades, but in that quiet, achingly slow way that speaks volumes to scientists and those few living close enough to nature, but escapes the mass of modern society. When scientists began ringing alarm bells, the clever propogandists swung into action. The subtlety and complexity of nature’s changes made it easy for them to paint twisted pictures of what was happening and what was likely to happen. Human behavior, wrapped in the flags of ideology and tribal identity, saw scientific truths as conspiracies. Beliefs were burned into place, indelibly so it seemed, and no argument or reason could be entertained, let alone considered; it would fall on deaf ears.
Then she raised her voice.
Truly ferocious heat waves in Europe, in Russia, Australia, India, Pakistan. Tremendous wildfires in the western U.S. Unprecedented flooding worldwide. Coastal flooding on a sunny day with no wind or rain or storm. And the hurricanes! Just to list them almost seems excessive.
This year, she didn’t just raise her voice. She roared.
Killer heat waves all around the northern hemisphere. Temperature in the 90s (°F) in the Arctic circle no less. Wildfires raging out of control, in Greece, in Sweden of all places, and of course in the U.S. where one fire destroyed the entire city of Paradise, California. And the hurricanes! In Florida, the one called “Michael” wiped another American town off the map.
We heard. This is bad
At least, we heard the main message: this is very bad. It’s not a nuisance, not just an annoyance, these changes we’re seeing are the things that kill people. They cost — in dollar terms, beyond billions to hundreds of billions and trillions. In human suffering, in lives destroyed, beyond imagining. And no one, no where, is safe.
The deeper messages are in all of nature, and among them are subtle but sometimes crystal clear messages that speak to scientists. They’ve been saying them for decades, but now perhaps, maybe, those so long blinded by ideology or ego, will finally start to take them seriously. For the human race, the important scientific messages are:
Climate change is because of us.
It’s going to get worse.
How much worse depends on what we do.
If you think 2018 was noisy, wait until nature roars really loud.
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But what about this:
[Response: What about it?
If you want to discuss the snowfall event in Austria, enjoy. But I caution you that this is not the place for random drive-by links to GWPF.]
Are you saying that a warmer atmosphere carries more moisture, and that when a large chunk of moisture laiden air cools, then lots of snow happens? And that with more warm moist air in the world we can expect heavier snowfall when the conditions are right? The conditions won’t be “right” as often, because it is warming. But when they are right, then heavier snowfall could be a consequence of a warmer moister atmosphere.
Indeed. That was the lesson of my childhood in Sault Ste. Marie–aka, “Snow Ste. Marie”, because of its propensity for lake effect snow off of Lake Superior. It was commonplace wisdom that the coldest winters tended to be less snowy, because Lake Superior would freeze, eliminating the lake effect.
Just to play with that idea a bit, I downloaded January total snow and mean daily temperature from the Sault airport station from 1957-2002. The dates were determined by available station data, here:
(The snow numbers are scaled down by 7x.)
The data are noisy and there’s not much visible correlation between the ‘wiggles’. But both temperature and snow show increasing trends.
Me, I’m not saying anything other than expressing confusion at conflicting reports. However, if warming causes more moisture in the atmosphere, should it not precipitate as rain rather than snow? Taking your argument further, we should ascribe warming to have caused the last ice age where more moisture caused more snow and ice. Do you see why I am confused?
[Response: Indeed the issue is more complex than it is often portrayed, and depends on both how much precipitation falls, and whether it comes as rain or snow. I suggest readers focus on that.
Regarding some recent strong snowfalls in New England: in an essay about it Mike Mann suggested that perhaps climate change will make nor’easters stronger because of intensified temp contrasts between warmer oceans and still-cold Arctic airmasses, as well as greater amount of moisture in the air from the warmer oceans. I’ve also heard the idea that snowfall may be enhanced by AGW-driven dynamics in a narrow spatial/temporal window where temperatures are just below the freezing point. However, when integrated across a nor’easter as a whole, total snowfall would be expected to decrease.
As for the current blizzard, Stefan Rahmstorf has an excellent tweet about some of the important things to consider.
vuurklip: “However, if warming causes more moisture in the atmosphere, should it not precipitate as rain rather than snow?”
vuurklip, *some* of it certainly will. However, consider the January data I graphed above: it shows that the mean daily temp rose from roughly -11 C to about -9 C. Clearly, the mean is still well below zero, so insofar as surface temperature is concerned, one would expect snow, not rain. (Of course in practice it’s the temperature aloft that matters most, but the same principle holds.)
During the same time, one sees the snow increase from ~70 cm to ~98 cm (the axis numbers represent multiples of 7 cm). Unless one can posit an alternate source for that snow besides ‘moisture in the atmosphere’–which I for one cannot–then moisture in the air increased over Sault Ste. Marie, ON, during 1957-2002, and precipitated as snow.
vuurklip: “Taking your argument further, we should ascribe warming to have caused the last ice age where more moisture caused more snow and ice. Do you see why I am confused?”
Yes, you are confused because you are trying to oversimplify things by assuming a single cause for everything. Specifically, while you are trying to account for the Ice Ages by considering amounts of snow that fall, that only accounts for one ‘side of the ledger’. What is more decisive for glacier formation and growth is the ratio of snowfall to snow*melt* over the course of the year. It doesn’t matter if more snow falls during the winter if it still melts out completely during the warm months.
So, hypothetically, if snowfall was reduced during the Ice Ages–and it probably was, as ice cores show significantly increased burdens of dust, suggesting conditions that were drier on a global scale–it wouldn’t prevent the formation and growth of glaciers, provided that the rate of melt also decreased enough to make a net gain in snow, over the course of the year.
(There’s also a feedback here, too, because the albedo effect kicks in as the ice grows: less sunlight is absorbed by the glaciated surface, which lowers temperatures further.)
If you push more moisture onto an alpine slope using an extra large snow-making machine, should it not precipitate as rain rather than snow?
Vuurklip, my question about the snow machine was actually a serious one. Why will you not ansdwer it?
therealbernardj: “If you push more moisture onto an alpine slope using an extra large snow-making machine, should it not precipitate as rain rather than snow?”
Sorry. Got sidetracked by so many responses. Anyway, to answer your question: It would depend on the ambient temperature. If it were warm enough, the produced snow would indeed precipitate as water.
Doesn’t the snow line shift upwards in warmer climates? Would you use your snow machine below the snow line?
“Would you use your snow machine below the snow line?”
Uh, why exactly do you think snow making equipment was invented in the first place? It is PRECISELY to make snow appear on the ground below the snow line.
“Uh, why exactly do you think snow making equipment was invented in the first place? It is PRECISELY to make snow appear on the ground below the snow line.”
However, below the snow line, moisture precipitates as rain (or the snow melts rapidly) – because it’s warmer there. And as it gets warmer, the snow line moves up – and if it gets warm enough, no snow at all – which is the opposite of “more warming, more snow” – or what am I missing?
Re. snowline versus snow amounts.
You seem to be confusing/reasoning with tunnel vision about the terms snow amounts versus snow location. There is nothing that I know of that says just because a seasonal snowline moves up or down during the winter that this has any effect on the amounts of snow we see where it does fall.
Further…while not a perfect analogy, but when you leave your freezer open does less “snow” form, or more as the freezer warms up? Well when large, frigid, bone dry air masses are drawn south (jet stream wobbles) and mix with the warm moist air forced up and around these masses, you get a lot of snow. This is basically the nor-easter mechanism we are seeing on the East Coast this year and have seen in vortex years in the past. There are other mechanisms in other areas. For example lake effect snows really need an open Great Lake. Too cold, no multiple feet of lake effect snow in Buffalo. So warming helps ramp up the snow amounts in that particular region at present.
Deniers as a group often operate by a misuse of Einstein’s dictum about a single fact bringing down a whole theory. I’ve even received many high school level lectures on this dictum from deniers over the years. But the thing they fail to realize or ever establish is that first they have to show that the single fact/factoid actually has a direct bearing on the theory. Snowlines/snowfall amounts do contain valuable climate information, just not the information you are looking for at the present time.
Hope this helps. But back to your OP, trust me: Ski resort capital is supremely aware of these things right now. And worried-to-downright-scared depending on specific location.
Here is just one paper you can download for free on the subject from researchgate…https://www.researchgate.net/publication/258437813_The_impact_of_climate_change_on_ski_season_length_and_snowmaking_requirements_in_Tyrol_Austria
Abstract: In this paper, the development and validation of a ski season simulation model (SkiSim 2.0) is described and results of the climate change assessment for 3 ski areas in Tyrol, Austria, are presented. The results of the validation process suggest that SkiSim 2.0 is an appropriate tool to simulate ski season lengths and snowmaking requirements at different altitudes and in different climatic subregions of the study area. Climate change impacts on ski season length are considerably less when incorporating snowmaking. All 3 modelled ski areas remain snow reliable until the 2040s (A1B) to the 2050s (B1). By then, current snowmaking technology has reached its technological limits. The required snow volume until the end of the century is projected to increase by up to 330%. Although snowmaking is a suitable adaptation strategy for the next decades, it is unlikely to be a sustainable adaptation strategy beyond the middle of the century. Besides altitude, local climate characteristics clearly influence ski season length, requiring the use of localized climate data.
Again, hope this helps.
JGNFLD: Thanks for your civil and reasoned response. I will study it and check the given reference. Just a pity that one gets saddled with the “denier” label for trying to understand someone else’s point of view.
“Just a pity that one gets saddled with the “denier” label for trying to understand someone else’s point of view.”
No one does. One gets correctly labeled as a science denier if they, well, deny science. I didn’t see you deny science above which is why I called deniers “they” not “you” here.
JGNFLD: Thank you! However others here did!
Gee, vuurclip, that’s a lot of snow!! Must have been a lot of water that got into that storm. I wonder if a warmer atmosphere which holds more moisture had something to do with it? Something to think about, isn’t it!!!!
Indeed, a lot of snow. But, with warming, I would expect this moisture to precipitate as rain, not as snow. I find it hard to make up my mind given that there are so many diametrically opposed views based on the same data. I do not profess to be able to determine the veracity of all these interpretations. So call me a skeptic regarding both sides of the argument.
I’m not sure what “diametrically opposed views” you’re referring to. There is the science of climate change, which gives a fairly clear picture of what’s happening and why. Then there are deniers who try to deny various aspects of the science (in some cases, deny all aspects of the science) but don’t present any convergent view on why climate is changing. There really aren’t two sides of “the argument.” There is the vast preponderance of scientific research, then there are the deniers who present many sides and they can’t counter the science (except with the odd paper or scientist that seeks to minimise the alarms or highlight the uncertainties in one way only). To claim that there are two sides to the argument is, to me, to be a denier. Apologies if you really are seeking the real story. If you are, stay tuned here or other sites, like realclimate.org, which put forward the science.
vuurklip. Dude. It’s the Austrian alps in winter. It’s cold up there in the winter. It can -and has – warm up a lot and still be below freezing up there. That means snow.
Your point only makes sense if you think that warming means that all temperatures everywhere are suddenly magically above freezing. I’m having a hard time thinking you actually believe that.
Lee: “It’s the Austrian alps in winter. It’s cold up there in the winter. It can -and has – warm up a lot and still be below freezing up there. That means snow.”
OK. but by that argument, the North Pole should have more ice the warmer the globe becomes – but I’m told that the NP will soon be ice free due to warming.
There surely must be a tipping point where warming causes less snow & ice? Where I live on a peninsula, we know that in times past the peninsula was a chain of islands, i.e. a warmer past with less land ice.
So I’m still confused
vuurklip: “OK. but by that argument, the North Pole should have more ice the warmer the globe becomes – but I’m told that the NP will soon be ice free due to warming.”
I am not sure where you are getting your information, but they are idiots. The science is saying we will (eventually) have an ice-free north pole during summer. During winter, it is dark for months on end. Of course it will re-freeze. What is more, you have to look at each situation individually–Arctic ice is sea ice. It freezes from the ocean up (mostly), not due to snowpack. In the Antarctic, we are seeing more snowfall inland, that is indeed competing with the melting we are seeing nearer the coast.
Please, do yourself and us a favor and get your science from reliable sources–not from denialist liars like GWPF or WTFUWT.
“North Pole should have more ice the warmer the globe becomes – but I’m told that the NP will soon be ice free due to warming.”
Did these same people mention to you that ice and snow are the results of two very different sets of processes at much different places and at different altitudes?
FYI, it is quite easy to find snow with no sea ice in the area and it is easy to find sea ice with no snow in the area.
And you aware that snow and sea ice are different things?
“And you aware that snow and sea ice are different things?”, yes, Lee.
“I find it hard to make up my mind given that there are so many diametrically opposed views based on the same data.”
When there’s an “argument” between science on one side, and not-science on the other, go with the science.
Lee: Thanks. However I find scientists like Murray Salby, Willie Soon, Roy Spencer, Judith Curry (and others) pretty persuasive – as I do Tamino’s analyses.
So for now, I remain skeptic about all of this, especially utterings like “the end of now”, “the burning planet”, “nothing to worry about”, etc.
[Response: Go read this:
Then let’s talk about Willie Soon, about how he publishes a commentary in a newspaper which is so foolish it’s trivially easy to refute, but HE NEVER BOTHERED TO INVESTIGATE IT SCIENTIFICALLY. That’s because when it comes to climate change, Willie Soon doesn’t act like a scientist at all. He’s a con man. He wasn’t at all trying understand sea level, he was only trying to push some real bullshit that would confuse people. In this particular case, the “con” he tried to pull is so amazingly stupid that if you personally fell for it, you should be embarrassed.
After we’ve dealt with Willie Soon, we can talk about Murray Salby and Roy Spencer and Judith Curry.
The “scientists” you seem to admire are misleading you, in many cases (like Willie Soon) deliberately (which isn’t just stupidity it’s dishonesty). Please, prove to us that you are not as easily made a fool of as they think you are.]
Talking about Salby: https://www.skepticalscience.com/salbyratio.html
Consider this carefully, Vuurklip. Yet another person you trust caught in a very obvious misrepresentation.
Nice article on Salby. “Hand, meet cookie jar!”
vuurklip: “However I find scientists like Murray Salby, Willie Soon, Roy Spencer, Judith Curry (and others) pretty persuasive – as I do Tamino’s analyses.”
Really, because I can honestly say that I have never come away from anything written by the above “scientists” with a better understanding than I went in with. They do not explicate so much as obfuscate. Most important, they do not predict, so they can never be wrong in their predictions. But what matters more in science is that they can never be right.
They offer as their excuse the contention that climate is so complex as to be unpredictable. And yet, there are thousands of climate scientists using current models and making prediction–many of which are proving correct, some speculative and a few just wrong. All of these are important–the validated predictions tell us what is right in the models. The speculations come up with useful extensions. And when you are wrong, you see possibilities for improving the models. Your so-called scientists aren’t even playing the game.
Vurrklip, you’ve literally answered your own original question, and yet the point still flew right over your head…
I found an article on marketwatch.com: Climate change has cost the government $350 billion — here’s what it will cost you. Citing the US Government Accountability Office, the article reports:
I’m in no way prepared to defend that specific numbers, except to treat them as a proposed floor, to be matched against any claimed positive benefits of climate change for US residents under the same conditions. Direct costs paid by the US government are, of course, a subset of total costs paid by US consumers. Are there other sources of cost numbers already incurred due to anthropogenic climate change, that you or commenters would recommend, Tamino?
Excellent post, Tamino.
Unfortunately, as the one named vuurklip demonstrates, deniers just can’t grasp the impacts of climate change. They can’t grasp that precipitation events are becoming larger. In winter, that means snow. And a wavy Jet Stream doesn’t help. Sadly, nature needs to roar even more loudly before people really take notice.
I am really confused when, on the one hand, I see a lot about warming and at the same time a lot of snow. But it is disappointing when I get insulted with the “denier” label for expressing this confusion. One apparently does not date ask questions (which is not the same as “questioning” if you get the subtle difference)
Sorry, it should be “dare” not “date”
“One apparently does not dare ask questions…”
C’mon, did it actually hurt to have someone call you that? You’ve also received neutrally-phrased answers attempting to explain where the difficulties are that trip you up.
On balance, I think you’ve received more of a gift of time, than the pain of insult. YMMV, of course.
Doc Snow: “C’mon, did it actually hurt to have someone call you that? ”
Regardless of the amount of pain this insult causes, it is just dumb to hurl insults in a civil debate. Roberts has no idea of what I am in denial of.
Climate is a complex issue and I could retaliate by inventing insulting labels to all those who are so absolutely sure that they know exactly how climate changes and what all the contributing factors are. It precisely this complexity which leads to different people to interpret the same data sets in diametrically opposing ways. Any one who is sure they fully understand climate change is in denial of reality.
” It precisely this complexity which leads to different people to interpret the same data sets in diametrically opposing ways.”
Actually, I cannot think of any cases where PROFESSIONALS looking at the same–global anyway–data sets interpret them in diametrically opposing ways. Or could you point some of these individual professionals and specific data sets out to us here? That would help much more than complaining about any insult you may or may not have suffered.
“Any one who is sure they fully understand climate change is in denial of reality.”
Anyone who is sure that climate science doesn’t have a good enough handle on the major variables in the field to make the consensus predictions they have made is in denial that science. Hence the word “denier”, you see. It’s an apt and accurate label for your position.
vuurklip: “Any one who is sure they fully understand climate change is in denial of reality.”
Oh, the strawmanity! Now where might I find a scientist who claims to understand climate change completely? Anyone? Beuhler? Complete understanding is not needed though. We certainly understand what is going on well enough to see that the current path does not end well. That is beyond question.
I do not fully understand gravity–to do so would require understanding fully the properties of space-time, cosmology, how gravity is connected to the other forces of nature… I don’t have to understand all of this to know that I should not jump off of a 30 story building.
There really is not controversy over the basics of climate change among actual informed, responsible climate scientists. Maybe you should listen to them.
Not only is that correct, there should be no controversy over climate change among people with collegiate training in physics and chemistry. Physics and chemistry don’t make any sense if you deny the principles that make climate change inevitable given greenhouse gas emissions. The isotopic chemistry that documents human causes of greenhouse gas emissions is fundamental. The accounting of greenhouse gas emissions from fuels burnt is irrefutable, and doesn’t come from science.
There are details of what happens to energies when they are here, but sea level rise, the Arctic melt, the disintegration of Greenland and Antarctic glaciers, and changes in the biosphere, including response of groups of animals, these are powerfully emerging evidence of it.
When you say “apparently one doesn’t dare…” you are implying that you must have suffered something adversive. I am, ahem, skeptical of the depth of that reaction–and in support of my interpretation, I’d note that you yourself seem perfectly able to push back on your own account.
So why not concentrate on matters of substance, with the many respondents who applied no label to you at all? You say you are ‘confused.’ Frankly–and I put this forward as an impression I get, not necessarily a ‘fact’–you seem a bit disingenuous.
I mean, is it really so difficult to understand that more snow can fall as it warms, so that provided the temperature remains below the melting point you have more snow accumulating on the ground?
Or that if warming continues, temperatures will eventually reach that melting point*, and only then will amounts of accumulated snow on the ground begin to decrease?
Or that if amounts of accumulated snow on the ground continue to decrease, they will eventually reach zero?**
*This is a corollary by transformation of the well-known Fudd’s Law: If you push something hard enough, it will fall over.
**Fudd’s Law, corollary #2.
Vuurklip, I can’t believe that you are as naive as you seem to be. But the reason you get confused with a climate denier is because you behave like one. Always shifting the argument, (Alps, arctic, its all the same…).
Being impressed by the arguments of Curry, Soon, Salby et al is telling. When you read explanations as to why they got things wrong, and it turns out that they did it willfully, knowing full well that their analysis was flawed, do you wonder why they did it? When they assert that there is a “pause” in global warming, do you ever wonder why you don’t see their article saying that global warming has started up again? If you are genuinely so naive that you don’t see that they are arguing in bad faith, then I strongly suggest that you delete all emails from Nigeria without reading them.
The warnings come not only when “nature roars”, but also when nature whimpers, as in the following account:
Wow, that is so scary.
Vuurklip, It would appear that you haven’t thought this through. So let’s do that. The warming we have seen has raised temperatures a few degrees. Does that mean that the temperature will never drop below 0 degrees C? No. And when warm moist air from the oceans cools as it rises up the slopes of mountains, what will happen to the moisture in that air. Some of it will drop as snow–lots of snow.
Likewise, a warming Arctic doesn’t mean you’ll never have the sea ice refreezing. Rather it means that ice persists for only a year or two at a time. You don’t have old ice, but fragile new ice. Anti-science sites like GWPF, WTFUWT, etc., take advantage of this seemingly inconsistent behavior to dupe the gullible. Don’t be one of their victims. If they had any real science, they’d be publishing in Nature rather than press releases.
Thanks. I accept your argument but would like to know if there is a “tipping point” where warming causes more rain than snow and if so where this is.
We’re already seeing this in the US mid-Atlantic states. Last year was the wettest on record–and most of it came in bursts of 2 inches at a time, or more. We currently have 6 inches of snow, but that is anomalous these days.
The thing about weather: it’s complicated. On average it is warming significantly. We’re getting much more rain than snow these days during winter. However warming is also decreasing the heat gradient from tropics to the poles. That weakens the Jet Stream and allows polar air from Canada to dip down into the Continental US, and so we can have snow storms into April or even early May. As you might guess, a snowstorm in April after a warm March confuses the hell out of the spring blossoms. We haven’t had apricots for 3 years.
Thanks you. This makes sense.
There is a much more complicated long answer which I myself do not actually know in full, but the short answer is:
From Krasting 2012 https://journals.ametsoc.org/doi/10.1175/JCLI-D-12-00832.1:
“Annual snowfall is projected to decrease across much of the Northern Hemisphere during the twenty-first century, with increases projected at higher latitudes. On a seasonal basis, the transition zone between negative and positive snowfall trends corresponds approximately to the −10°C isotherm of the late twentieth-century mean surface air temperature, such that positive trends prevail in winter over large regions of Eurasia and North America. Redistributions of snowfall throughout the entire snow season are projected to occur—even in locations where there is little change in annual snowfall. Changes in the fraction of precipitation falling as snow contribute to decreases in snowfall across most Northern Hemisphere regions, while changes in total precipitation typically contribute to increases in snowfall.”
Scientists who study snow have found that the boundary is atpproximately the -10C isotherm. There are tables that show this line for every month.
Arctic sea ice forms in place while snow fals from the atmosphere. Since they are completely different processes they are affected differently by climate change. When it is warmer., ice forms more slowly and melts faster so there is less ice. When there is more water in the air it snows more.
Skeptical Science has had several deniers this week posting about snow cover. Did WUWT have a snow article?
Told ya there was a long answer…!
I’d like to give you a real world example of what a warming climate is doing in a place that used to be noted for its large annual snowfalls, central Maine where I live. 30 or 40 years ago, most of the snow that we received used to be of the light and powdery variety that fell from periodic storms that would pass through the Gulf of Maine while keeping us in very cold air (usually -15C to -10C at the height of the storm) We would occasionally see rain during the winter and even have temperatures with such storms getting up to +15C if a storm would pass by to our west and pull a lot of very mild air into our region. But those situations were very rare and usually only happened once a year or every two years. The preponderance of storms went to our east and kept us in the cold air while dropping that very light and powdery snow that was way more common.
But over the last 25 years we’ve seen a steady increase in situations that have brought rain and freezing rain to our region though we still can get monster snow events if things line up just right. But the chances of having the old fashioned powdery snow events have steadily declined until now they have actually become relatively rare! Most of our snow now tends to come as the heavy, wet variety with temperatures typically in the range of -5C to 0C. We have also had significantly more total precipitation during most years including the winter season, though we’ve tended to see it coming as more and more rain or freezing rain and less and less as plain snow of any variety of moisture content. Such things are exactly what one would expect with a warming climate which enables a lot more moisture to be involved with storms, but which still allows huge snowfalls to occur if temperatures are just cold enough to keep the precipitation falling as snow.
I would also like to give you a quick primer on typical mid-latitude precipitation mechanisms. It turns out that most mid and even high latitude storms use the accretion mechanism to generate ice crystals near the freezing level which is typically about 2-3 kilometers in elevation with a typical low pressure system. At the freezing level, there are molecules of water vapor as well as liquid water droplets and ice crystals. The more moisture that gets pulled into the system, the more of each form of water will be found and the more snowflakes will be generated near the freezing level at about 2-3 kilometers up. If temperatures all the way down to the surface are colder so that all levels are below freezing, the snowflakes will remain snow all the way down to the surface and pile up there. But if there are layers of warmer air circulating below the main freezing level aloft, they will cause the snowflakes to melt into rain and fall to the surface as such. But if there is still a colder layer right near the surface that hasn’t been dislodged so that temperatures remain below freezing, the rain will freeze on contact or else fall as sleet which is rain that has refrozen before contact. The more the atmosphere warms in general, the greater chance that lower levels will see layers with temperatures above freezing and lead to rain or freezing rain depending on where those warmer layers happen to be. But if the lower layers are just a bit below or just right at the freezing point, the precipitation will fall as snow. The more relative warmth, the wetter the snow and the more relative cold, the drier the snow. But it’s still snow!
To summarize about our situation here in central Maine, we’ve seen a dramatic warming of average temperatures over the last 40 years that have changed our winter from generally cold, dry ones with powdery snow to relatively milder ones with a lot more rain and freezing rain events mixed in with the snow which has generally become wetter and stickier as temperatures warm. Kids 40 years ago had trouble making snowballs because the snow wouldn’t stick; but today snowballs are much easier to make with the wetter and stickier snow that tends to fall more frequently. That wetter snow is also much heavier to shovel and plow and tends to freeze into solid stuff that has the consistency of concrete and so takes longer to melt in the spring! That is what I would call dramatic climate change to a warmer world in central Maine!! It’s also similar to what they’re seeing in the Alps (which are also losing most of their iconic glaciers!) as well as other parts of the world that still are able to see snow whenever the lingering cold air has a chance to move in.
Finally, you asked about a tipping point to where all precipitation would just fall as rain. That would imply that there is no cold air anywhere that would be cold enough to make snow happen. That would be similar to what the Earth was like 50 million years ago when tropical plants and crocodiles lived in the Arctic and a third of North America was under water from much higher sea levels because there was no permanent surface ice. I think any reasonable person would have to admit that our civilization would really be in trouble if that happened! But with atmospheric carbon levels heading in a similar direction and doing so at a much higher rate than what happened back then, it’s not too much of stretch to think that we might soon find out if we have in fact already reached that tipping point!
Hope this clarifies things for you.
Delightful explanation, Ed. Can you toss some standard meteorologist terminology onto that? I sometimes have attended a meteorology conference and while I might be able to access a standard glossary, I sometimes don’t know the shorthand terms the meteorologists are using. Things like gradient advection or CAPE.
Ed Hummel: Many thanks for your detailed explanation. Helpful indeed
*sigh* Global warming never means or meant uniform, synchronized warming everywhere. That is a creature of an imagination which cannot contemplate something more complicated. Global warming means, on average, the temperature of the globe warms. Period. Sure, there are excursions here and there. Sure, Clausius-Clapeyron says more moisture will be in atmosphere.
But, as in New England, where I live, south of Boston, these do not synchronize, and they can result in devastatingly high snowfalls, if the cards fall right. That will continue, at least for a couple of decades. Thereafter it will be rain.
Facts are, burst precipitation is more the signature climate change event than warming, even if warming is a long term problem, especially in summer drought.
Excellent point about the burst of precipitation, Ecoquant.
I see you live south of Boston. I grew up in New Bedford back in the 1950s and 60s and have lived in central Maine for the last 37 years. Over that time I’ve noticed that our climate here is becoming more like what I remember growing up “down south”!! We can actually have snowball fights here more often though there’s also a lot more slush than we used to have!