The question arises: how might temperature variation have changed? We all know (if you don’t already, then read this blog!) that things like temperature show a combination of trend and fluctuation. We almost always focus on the trend, because that’s what shows the most obvious changes over time. But those fluctuations … the “noise” that we add to “signal” to get “data” … the “variation” we add to “average” to get the “weather” … are they changing too? Or are they just doing the same old same old kind of fluctuation they’ve been doing all along? This is a very different question than we usually hear about in discussion of climate change, not about a change in the average temperature, but whether or not the fluctuations have somehow changed.
They’re prominent in today’s news on two continents. The great plains of the USA are shivering through some of their coldest temperatures on record as the “polar vortex” invades from the north. Meanwhile, Australians suffer through their hottest month and worst heat waves ever, hell on earth for a place already known for it’s heat.
But mainly, it’s that polar vortex thing. Some have suggested that the rapid warming of the Arctic compared to the rest of the world, plus the dramatic decline of Arctic sea ice, have changed things in a fundamental way. It has thrown a monkey wrench into the jet stream, and during winter it can cause the polar vortex to fragment, part of it diving southward and bringing the deep freeze with it.
As a first glance, I’ll look at monthly average temperature for a specific region, in the northwest corner of Maine. It’s one of the grid boxes for the Berkeley Earth Surface Temperature gridded data set, and here’s the temperature anomaly throughout time, for the winter months (Dec/Jan/Feb) only:
The solid red line is a smooth fit. It too fluctuates rapidly (probably too much, but it certainly captures what’s going on with the signal. But it captures too much of the noise, so we shouldn’t use it to estimate the trend.
But we can use the residuals — what’s left over after subtracting that smooth — to estimate how the noise may have changed over time:
It certainly looks like they’ve tended to get bigger over time. But “looks like” is poor statistical analysis. Let’s look at the squared residuals, which will all be positive:
That doesn’t just “look like” it’s increasing over time, statistical analysis backs up that conclusion.
You might suspect that I used the gridded data from Berkeley Earth because I intended to do all the grids, not just northwest Maine. Right you are.
I took just the data since 1900 (I’m not so interested in what happened before then), fit a straight line, then analyzed the residuals to look for a change in variance. Here’s a map, with red dots where the variance seems to be going up, blue where it’s going down, larger dots for faster changes:
The greatest change is happening in a ring around the Arctic circle. Imagine that.
By no means is this a sufficiently rigorous analysis. It would be better, I think, with daily rather than monthly data (and I think Berkeley Earth provides a gridded data set for that too). A better smoothing method could be settled on, a better way to define what’s the probably “noise,” and a better way to define how things truly vary.
But at least it’s a start. If we take a close-up at the results near the USA, we see this:
The eastern USA has, overall, seen an increase in variance, while much of the western USA has seen a decrease. What will the future will bring?
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Have you seen this type of analysis done with River Gauge data? I’ve anecdotally observed significant change in the high water pattern in the Mississippi River at LaCrosse WI. Spring like water levels at various times of the year, including winter.
Anyway, thanks for your work!
By fitting a straigth line you will pick a lot a residual from the accelaration. Also, there is a question about the system drift over time. For example, daily fulctuations are not stable.
The result would be more robust stating at 1980.
Heller has a post loosely related to this, of course his data shows the opposite trend, surprise, surprise! He attacks an article by Heidi Cullen which supports the idea of winters warming.
I went to the realclimatescience website, I’m confused, what am I missing that the data used there comes to the opposite conclusion?
[Response: Your first mistake was giving any attention to Tony Heller.]
I’m also confused by the USHCN time series. “Climate at a glance” shows the opposite, a Midwest warming trend, 1918 to present:
Is there an easy way to access the USHCN temperature records for comparison?
Heller uses all reporting stations in the Midwest. Since new sites are added over time that affects the result when you use all sites and do not weight the values. If more sites are added in the Northern Mid-West than the Southern Mid-West, the temperature goes down over time because it is more biased to the north.
Tamino uses data that has been normalized over the area he looks at. When new sites are added they average them with nearby sites and the final reported value is adjusted so that all areas have the same weight.
There may be additional problems with Hellers data that I do not know.
Heller scours the internet for data that can be used to decieve the unwary. He has such a bad reputation that they won’t post him on WUWT.
Bill, Heller’s schtick is to use the “raw data”–i.e., data which is not homogenous–that is, which lacks corrections for known biases. You see, over the years changes in instrumentation, observing times or procedures, and station location can introduce (and have introduced) biases into temperature (and other) records. Real scientists work out what those biases are and correct for them so that we can tell what is going on. And they document what they did in mind-numbing detail.
Heller calls that ‘tampering’ and believes, or claims to believe, that it is done fraudulently in order to promulgate a political agenda. Hence, he also claims to use the raw data, as mentioned above. You may have noticed that I put the phrase in scare quotes the first time I used it. That’s because Heller also doesn’t give you links to said data, or any but the vaguest attribution, so it’s pretty much impossible to tell what he’s actually done. For all anyone can really tell, his ‘data’ are actually fabricated from whole cloth.
Heller’s thing is that he insists that the it’s just as warm early in the morning as it is in the afternoon.
If he accepted that it’s warmer in the afternoon, his whacky conspiracy would fall apart. His entire thing is literally built on the idea that the Sun doesn’t heat things up during the day.
Bill, what you are missing is that Tony Heller is a lying sack of rat feces, but hey, as long as his lies are the ones you want to hear, you can avoid thinking, amirite?
As others have noted, Heller is not an honest broker. His MO is to produce context-free factoids some of which may even be true/true-ish but NONE of which actually lead to the “obvious” inference you’re supposed to make.
One of his more famous “true” factoids supposedly “disproving” the recent huge reductions in Arctic sea ice was to find an article from the 1920s noting there was no ice around Svalbard for a short time. This, you are supposed to infer, “PROVES!!!!!!” that there was no ice in the entire Arctic in the 1920s. Sure there wasn’t. Turns out other people found a lot of ice elsewhere and recorded this in logs which have been and are now being analyzed. But Heller “accidentally” fails to inform about this fuller context.
Hint if you’re scientifically unwary, Phil: “Conclusions” simply do not follow from pretty much 100% of context-free, isolated factoids even when said individual factoids might even be true. Science marches on through getting context-RICH data and analyzing it appropriately.
That Bill, not Phil.
I read up on Heller after my last post, including this:
Actually, Greg Laden is far too kind to Heller–the latter doesn’t do science at all. It’s propaganda all the way down.
Potholer 54 has had an excellent debate on you tube with Mr Heller over the last month or so.
Potholer has deconstructed Hellers nonsense with his usual dry wit and impeccable references to the peer reviewed literature.
already known for *its* heat :-P
Would it be useful to take the standard deviation of temperature over, say, 5 years, and see how that’s gone up with time?
Thanks Tamino. However, here in southwestern Washington state I haven’t noticed any decrease in the “variance” of winters over the last 48 years. What is noticeable is that winters are now warmer, which means more slick ice. Used to be cold enough to make crunchy firn underfoot for most of the winter. Also, now there is fog more frequently.
@BPL & DBB — I did an analysis related to your comments (and to Tamino’s piece), although rather limited in scope. In honor of the current polar vortex, I downloaded and analyzed January temperatures for Minneapolis from 1970-2018. Specifically, I compared means, standard deviations, 95% confidence intervals, minimum and maximum temps for two periods: 1950 — 1970 and 1998 — 2018. Again, January only. There were 651 days in each period. Results as follows:
For daily lows:
Period……….Mean……….S.D. ……….95% CI……….Min……….Max
For daily highs:
So, for daily lows, the latter period averaged 6.67 degrees F warmer than the earlier period. This is outside of the 95% C.I. for either period. Note that the SDs and 95% CIs are not very different (actually slightly lower for the latter period). Similar conclusions pertain to the daily highs.
So there was warming, but no apparent increase in variability for this selected data set. As has been noted elsewhere, the daily lows seem to be rising faster than the daily highs.
Data was downloaded from NOAA (NCDC), and is for the Minneapolis-Saint Paul International Airport station (near where I used to live).
One should be careful analysing gridded data for changes in variability. With changes in the number of stations also the variability changes. If a grid box contains a station it will show more variability than when the value is interpolated based on surrounding stations. On the other hand, a gridbox with one station will be more noisy than a gridbox with many stations. So it can go both ways and it is a good idea to see if the same patterns can be seen analysing the data of single stations.
Melbourne’s ‘The Age’ newspaper has just published a truly excellent summary of what has happened climactically in Australia in January (and is expected to continue for months):
‘Dome of hot air’: Australia blows away heat records
Maximum temperatures in January
Australia +3.37º highest (was +2.46 °C in 2013)
Queensland +2.39º 5th highest
New South Wales +6.15º highest (was +4.11 °C in 1939)
Victoria +4.61º highest (was +3.69 °C in 1981)
Tasmania +3.22º highest (was +2.99 °C in 1961)
South Australia +4.66º highest (was +4.50 °C in 2001)
Western Australia +2.33º highest (was +2.21 °C in 2008)
Northern Territory +3.71º highest (was +2.88 °C in 2013)
Another update from the Antipodes:
Australia’s extreme heat is sign of things to come, scientists warn
Australia sweltered through the hottest month in its history in January, spurring mass deaths of fish, fire warnings and concerns among climate scientists that extreme heat is hitting faster and harder than anticipated.
For the first time since records began, the country’s mean temperature in January exceeded 30C (86F), according to the Bureau of Meteorology (BoM), which said daily extremes – in some places just short of 50C – were unprecedented.
“There’s been so many records it’s really hard to count,” said Andrew Watkins, a senior climatologist at BoM, after January registered Australia’s warmest month for mean, maximum and minimum temperatures.
Further to my previous two comments — I’ve noticed that discussions about Australia’s current weather patterns now by default end with a big sigh and the lament “We’re fucked”.
We are fucked. It’s in the bank. There’s too much inertia in the global climate system, and in human response to the effects of our emissions, and there’s too little capacity remaining in our ecosystems to absorb the escalating impacts.
At some time in the not-too-distant future things will reach the point where they break irrevocably… and people are too afraid to make this point in the mainstream. Heck, half our politicians are still pretending (or behaving as if they are) that there’s no such thing as ‘greenhouse’ gas-caused planetary warming.
It pisses me off mightily that the nature of the locked-in consequences are still not publicly acknowledged and discussed. As long as we continue to pretend that we’re not hurtling toward and implacable wall we will not properly understand what it is that we need to work to try to mitigate.
I think you need to consider your messaging. You said, for example:
If I read a passage like that, I’m going to conclude the only sane, logical response is “carpe diem”. Screw mitigation, it’s pointless anyway! I’ll be in the bar if you need me. Hell, that’s why certain denialati went from ‘no warming’ to ‘unstoppable warming.’ Either way, action was repressed.
I don’t even like the ‘implacable wall’ imagery, because I don’t think it’s an accurate metaphor. There isn’t going to be a moment of collective impact and excruciating pain, followed by oblivion. It’s going to be a twisting, unpredictable journey into an ever darker, more threatening landscape, in which tragedies and losses pile up, eroding our capabilities, will and spirit. Eroding us.
But until the moment oblivion claims us, we have choices. They’ll be fewer and worse the more we permit BAU to continue, but they’ll be there, and we won’t be able to evade them.
We are fucked, to a certain extent; we’ve lost good people, in at least hundreds of thousands now (more likely in the millions). We’ve lost at least hundreds of billions of dollars (more likely in the trillions). We’re rapidly losing the coral, we’re rapidly devolving into commitment to loss for many coastal cities, and rational betting on the Arctic sea ice isn’t if we lose it, but when.
But there are still pathways to containing the damage. We need to make sure we make the right turns going forward. And for that purpose, despair is not adaptive.
I find the whole “we’re fucked” approach frustrating and misleading. It may be that we cannot avoid significant consequences due to warming. However, by not acting, we will definitely increase the severity of those consequences. There is a metric shit-ton of difference between 2 degrees warming and 4 degrees warming. And if we get to 6 degrees, it is going to be a very bad couple of millennia for anything that breathes oxygen.
So my recommendation is to keep pushing ’til you suffocate.
Without being alarmist,
We will lose coral reefs and the ecology’s that depend on them.
Sea level rise is going to continue to accelerate reaching 10mm or more a year by the end of the century.
We will see cat 4, 5, even 6 storms at an increasing frequncy.
Weather will continue to become more unstable and unpredictable effecting food security. Permafrost melt will increase. Ice outside of polar regions will shrink and mostly disappear, Major ecological loss will accelerate.
Are we fucked?
Who is we?
Most of “us” live in first world nations that will take a dent in GDP but else wise get by .We can afford to pay more for food, move infrastructure, guard our borders against the hordes of displaced and survive.
Somewhere between tens of millions to billions of the not so fortunate will die. The worlds poor will be the truly fucked .
I like the way Mann (I think) put it: It’s not a matter of Fucked or Not Fucked, but rather HOW Fucked. It recognizes that there are locked in impacts, but that we can limit those impacts.
That said, people do tend to think in binary…
As for Australia, while the south east is hot, consider the lot of Townsville in northern Queensland. They are used to getting good rain but over the last week they have had over 1100 mm or 43 inches; a record. And expecting much more over the next few days.
And some of the politicians are still maintaining that they don’t believe in Global warming. (Sigh!)
Perhaps those who advocate “Don’t despair!!!” have a point: Despairing can lead to BAU behaviour. But providing hope that “we MAY be able avoid catastrophe if only we follow these paths” says to the majority that there is nothing to worry about just yet and that “the smart people” will save us from ourselves with something pulled from a hat at the last moment.
As a populace, we are not going to take this seriously until enough people are saying “we’re fucked!!!” When “the smart people” are all saying it, maybe something will change.
Until then, it’s BAU.
Look around: Nobody is acting seriously to prevent anything other than BAU. What will change that behaviour?
That’s an idea you frequently hear, too, but frankly it puzzles me a bit. I certainly wouldn’t claim that we are where we need to be, or even close.
–We’re roughly a factor of 10 better with alternate energy than anyone could have dreamed 10 years ago, with deployments soaring and costs failling
–Increasingly, this is leading to retirements of fossil fuel capacity, especially coal
–We finally have a comprehensive agreement including all the emitters of any significance (and the US will either not leave, or will rejoin)
–The number of jurisdictions imposing carbon prices via various mechanisms continues to increase, with Canada being the latest G8 economy to join that particular club
–Jurisdictions around the world are setting ambitious RE goals
–Ditto, eliminating ICE vehicles
It’s not sufficient, yet. But it isn’t ‘nothing,’ either. And the result isn’t BAU.
Because despair is such an inspiring message! “Workers of the world unite; you have nothing to gain.” Wow, I’d march behind that banner!
As I said before, the problem with the “We’re fucked” message is that it doesn’t correspond with our situation. It’s not a question of whether we are fucked–it’s how fucked we are. And anything that prevents action–including resignation and despair–makes things worse.
Recently I read a denialist blog article ridiculing the link between the cold experienced in the US and AGW. The author refers to the theory, pushed by Jennifer Francis, which explains the extreme weather as the meanderings of the jet stream bringing arctic air into the US. He states that the theory is not widely accepted amongst scientists and even quotes a well known climate scientist, not a denier, to support his skepticism. Predictably he also quoted a well known denier scientist who thinks the theory is nonsense. However, as in all other aspects climate change denial, no alternative theory/explanation is put forward to explain why polar air is coming so far south. From the knowledgeable people here I’d like to know how much support there is amongst the climate change scientific community for linking the warming arctic to the excursion of frigid air from the arctic, and what other explanations are there.
[Response: I’ll start, and hope others will add their opinions and knowledge.
We have reduced the equator-to-pole temperature gradient. It makes sense physically, that this will increase the “meanderings” of the jet stream. The loss of Arctic sea ice also dramatically affects heat flows in (and to and from) that region, and it simply doesn’t make sense that this won’t affect the jet stream and how it interacts with the “polar vortex.”
However, I haven’t seen enough hard data to confirm that this is taking place. There are hints, but I haven’t yet seen the case made solid. That doesn’t mean the case isn’t made, just that I haven’t seen it yet.
My impression is that the majority of climate scientists consider Francis’s theory fundamentally sound, but of course there are skeptics too.]
Although I don’t suggest posting links to denialist claptrap here, it would be helpful to know at the very least which dumbass we are refuting here.
My impression of Francis’s theory is that it is theoretically sound for the reasons Tamino has cited above. It is somewhat speculative, but speculation followed by investigation is how science advances.
The denialati don’t care about any of that–the noises they make all have the same information content–regardless of the which end of the food tube they originate from.
I recall that Kevin Trenberth was pretty skeptical about the Francis/Varvus hypothesis initially, saying that the physical mechanism was not well developed. (Which I presumed, perhaps wrongly, to mean that it had not been modeled in any quantitative detail.) But there was work done to solidify that side of it–don’t remember the author, but theoretical stuff involving teleconnections, Rossby waves and the like, if I recall correctly.
Francis and Vavrus followed up with a more observational paper in 2017:
As George Box said, “All models are wrong; some models are useful.”
The great thing about science is that it allows us to progress by being wrong, and being wrong is something humans excel at.
Thanks Tamino, Doc and Snark for your replies. Don’t quite understand the reasons for the reluctance amongst mainstream scientists to accept the hypothesis if the mechanism makes sense and is what you would expect to happen, but then again I don’t know much about science so I guess that’s the scientific process at work and things take time. Has some modelling of the mechanism been done which produced something different to what has been observed?
[Response: I can explain the reason for the reluctance. We’re skeptical. It’s one of the defining characteristics of most scientists.]
Tamino’s answer is pretty much nuts on. You advance science by proving ideas wrong, not by proving them right. You only accept a hypothesis once it becomes absolutely essential to understanding the data–and even then the acceptance is provisional until something better comes along.
The NCDC temperature records page seems to be down because of the government shutdown.
In their report for January this is what the NSIDC had to say about the “record cold” weather in the USA during January:
“Conditions in the upper US Midwest were colder than any previous winter period in the past two decades. Low temperatures in northern Minnesota and all of Wisconsin on January 30 and 31 were in the -27 to -35 degrees Celsius range (-17 to -31 degrees Fahrenheit). Large areas of Michigan, Ohio, Indiana, Iowa, and the Dakotas reached temperatures below -20 degrees Celsius (-4 degrees Fahrenheit). However, few all-time low temperature records were set during the cold snap. Very mild conditions followed the cold snap in early February.” http://nsidc.org/arcticseaicenews/
Coldest in the past two decades, some “record cold”. The media is led by deniers to report record cold when it is only cold for a warmed world. In the 1920’s the January cold snap would have been cold but not exceptional. People have forgotten how cold it used to be.
Cliff Mass was right, the cold snaps are warmer and rarer than they used to be. I cross posted this at Skeptical Science.
Is this the page you were looking for? It displayed OK for me:
(And seems to be up-to-date, as best as one can infer from the data. I wish they’d put a tag IDing the last update time, just for clarity.)
RGHE theory says the atmosphere performs similar to a greenhouse, “trapping” energy making the “with” it atmosphere 33 C warmer than “without” it, i.e. 288 K – 255 K.
The 288 K is a WAG pulled out of WMO’s butt. The 255 K is an unrelated S-B calculation for the average 240 W/m^2 OLR at ToA (got it? w/ atmos!!) requiring a 30% albedo.
The earth w/o atmosphere cannot have a 30% albedo, more likely 14% like the moon.
The atmosphere is not like a greenhouse, it is like that reflective panel you put behind your car’s windshield. By reflecting away 30% of the ISR the w/ atmosphere COOLS the earth compared to w/o.
In actual physical and mathematical fact removing the atmosphere exposes the earth to 20% to 40% more kJ/h and the ASR temperature increases 20 C to 30 C. That’s warmer not colder.
The greenhouse effect does not exist and 30 years of crap science stacked upon it goes straight in the trash.
(If you don’t understand the acronyms maybe you should do the homework.)
[Response: Thanks for a good laugh.
Every village needs an idiot. Your application will be processed promptly.]