### Why extremes are expected to change with a global warming

Filed under: — rasmus @ 5 September 2017

Joanna Walters links extreme weather events with climate change in a recent article in the Guardian, however, some  reservations have been expressed about such links in past discussions.

For example, we discussed the connection between single storms and global warming in the post Hurricanes and Global Warming – Is there a connection?, the World Meteorological Organization (WMO) has issued a statement, and Mike has recently explained the connection in the Guardian.

We still cannot say that single events are caused by climate change for the simple reason that climate change is not a force.

Rather, climate change is a consequence of changed physical conditions. Indeed, one type of climate change could hypothetically consist of storms just becoming more powerful.

I will explain what I mean with climate change below.

If you want to understand the world, then statistics can provide some insights if you have a large number of observations or measurements. This is especially so if you live in a very complex universe with a lot of complicated factors and it is difficult to solve all the equations representing the physics.

To distill information about the climate, you can sort weather data according to different categories, such as magnitude. Then create a table keeping a count of the number of cases that fall into each category, and you will be able to see what magnitudes are common and what range within which you expect them to fall.

You can also plot this type of statistics as a figure known as a histogram.

The histogram is a crude way of showing how frequently you can expect the measurement to fall into each category.

The frequency is proportional to the probability, and you can fit a smooth probability density function (pdf) to the data.

Typical examples of pdfs include the bell-shaped normal distribution for temperature (left panel in the Fig. 1) and the exponential distribution for 24-hr precipitation (right panel i Fig. 1).

What I mean by climate
I usually say that climate is the same as weather statistics (or more precisely, the statistical characteristics of meteorological variables), providing information about what type of weather to expect and its probability.

This statistics, however, will not tell you what one particular outcome will be (i.e. a weather forecast) nor is it a force that influences the outcomes.

The statistics is a mere reflection of (hidden) underlying forces of physics.

Global warming is one kind of climate change caused by an increased greenhouse effect with an impact on both meteorology and the hydrological cycle. It involves physical conditions which set the stage for evaporation, convection, condensation of water vapour, formation of clouds, and precipitation.

Statistical parameters are surprisingly predictable, and weather statistics is systematically influenced by the physical conditions present.

This dependency to physical conditions is evident from how the temperature and precipitation vary from place to place: typically warmer at low latitudes and cooler at higher altitudes; more rain near the coast and less in the interior.

There is also more intense rainfall in the warm tropics than the cooler extra-tropics, and summer precipitation is often more intense than in winter due to different physical conditions.

Typical probability density functions (pdfs) of temperature (left) and precipitation on rainy days (right).

What I mean by climate change
One definition of a climate change is a shift in the pdf describing the temperature, precipitation, or some other variable.

Such a shift in the pdfs is illustrated in Fig. 1 where the grey shading represents the original climate and the red shading a changed climate.

Some variables are strongly affected by changes physical conditions, others are less so. One indicator for their sensitivity to a climate change can be how their character depends on the season, geography, natural variations, or if they exhibit pronounced long-term trends.

Different kinds of extremes
Extremes are often defined as the tails of the distribution (upper or lower parts of the curves in Fig. 1), which are associated with low probability but magnitudes near observed ranges. The magnitude can be either very high (e.g. heat waves, heavy precipitation, intense wind speeds) or low if the pdf has two tails (e.g. freezing temperatures).

The expression “weather extremes” is a catch-all phrase, and not very useful for describing the actual situations. There is a range of different types of extreme weather events, with different nature and different manifestations.

For instance, there are conditions which are present all the time, such as temperature or barometric pressure (there are no days without temperature or pressure). These can be described by one single pdf to indicate their magnitude at any time.

Some conditions are intermittent, such as rain (it doesn’t rain constantly all the time). There are two aspects characterizing intermittent phenomena: how often do these phenomena take place and how intense are they.

For intermittent phenomena, you need two pdfs: one describing their presence (e.g. a Poisson distribution) and one indicating the magnitude when their are present (e.g. Fig. 1).

Some meteorological phenomena are both rare and violent, such as tropical cyclones, mid-latitude cyclones, tornadoes, hail, and lightning.

The more frequent they are, the greater the chance for seeing very extreme events just because you get a larger sample of events over time.

We can use these ideas as a context for Joanna Walters’s article and Hurricane Harvey.

Tropical cyclones
One thing is that global warming may have boosted its force, but will a global warming result in more frequent tropical cyclones?

The oceans are warming, and these hurricanes represent one mechanism that moves the heat from the surface to high levels in the atmosphere where it can escape to space.

We know that the number of tropical cyclones is influenced by several factors: the seasonal cycle, the geography, ocean temperatures and the wind structure in the atmosphere.

According to the IPCC AR5, however, there are little indications of a change in the number of tropical cyclones, although they are becoming more intense (p. 107, TS.5.8.4 Cyclones):

that it is likely that the global frequency of tropical cyclones will either decrease or remain essentially unchanged, concurrent with a likely increase in both global mean tropical cyclone maximum wind speed and rain rates

I believe the jury is still out on the question of the number of tropical cyclones because the IPCC’s assessment has so far not included studies on the relationship between the number of tropical cyclones and the area of high sea surface temperature, such as the analysis shown in Fig 2 (1).

Fig. 2 shows predictions with a simple model that predicts the number of tropical cyclones (NTC and n) in the North Atlantic based on the area of warm sea surface (A) and the NINO3.4 index. It was created in R using the script tropicalcyclones.R which also retrieves the data. The model was calibrated over the period 1900-1960, and the predictions provide reasonable similar evolution of the North-Atlantic tropical cyclones outside this period. (PDF-version).

The analysis in Fig. 2 shows a crude prediction of the number of tropical cyclones (n) in the North Atlantic based on the area of warm ocean surface (A), and we see a roughly similar trend in these predictions as in the HURDAT2 tropical cyclone record.

One caveat with such empirical studies, however, is that the data record is incomplete and there is a risk that the analysis presents a false picture.

Nevertheless, the IPCC AR5 presents an outlook of increasing extreme precipitation in tropical cyclones making landfall (p. 106, Table TS.2), which is relevant for the flooding connected to Harvey.

Flooding may also become more severe from changes in the landscape, as explained by John Vidal in an article in the Guardian.

I think Joanna Walters’ article about extremes and climate change describes the current situation well, and we should not be too surprised.

A change in the pdf reflects a climate change, and in most cases its range and tails tend to follow the part of the curve that represents the more common conditions.

We must assume that it is only the exceptional cases where the tails of the pdf are unaffected. Furthermore, an increase in the number of tropical cyclones would increase the number of more cases with extreme rainfall.

## References

1. R.E. Benestad, "On tropical cyclone frequency and the warm pool area", Natural Hazards and Earth System Sciences, vol. 9, pp. 635-645, 2009. http://dx.doi.org/10.5194/nhess-9-635-2009

### 277 Responses to “Why extremes are expected to change with a global warming”

1. 251
Victor says:

#243 MA Rodger, addressing Brian Dodge @235:

“I think you are cruel presenting Victor the Troll with a double negative. He is too much of a simpleton to cope with such a logical construct. Look how he flounders @238 replying to you. You’ve got him saying that “more aerosols” will have “slowed the cooling effect of said aerosols” which is plain bonkers. We have to keep it simple. The troll is not just incredibly stupid. His is also in denial. That is a heady mix to grapple with.”

For once I have to agree with Mr. Rodger. I AM a simpleton, and that statement was obviously wrong. I noticed that shortly after I submitted the comment but was hoping no one else would notice. So that makes me devious as well as stupid. All I can say in my defense is that Brian made me do it. Because his assertion was so damned convoluted it made me dizzy and prevented me from thinking straight.

So my apologies to everyone who might have been harmed by my little micro- transgression and I’ll try not to let it happen again.

Now let me give it one more whirl. Brian wrote:

“How, pray tell, would volcanic aerosols “dissipate” if there were no lack of volcanic activity continually replenishing them?”

My new (and improved) response:

What he really means, of course, is that additional volcanic activity, had it taken place, would have added more aerosols, thus slowing the overall dissipation, which would in turn have enhanced the cooling effect of said aerosols. True enough. So a lack of volcanic activity must have the opposite effect, and result in warming. Put that way, it sounds reasonable, enough, no?

To understand the flaw in this reasoning, let’s once again consider an air conditioned room. Only this time it’s a really large room containing several air conditioners. Now if the air conditioners are turned on one at a time, each addition will contribute to the cooling of the room, obviously. But that is NOT the same as saying the room would warm up if NONE of the additional air conditioners were turned on. And obviously, it would not.

If a lack of air conditioning cannot warm a room, then I fail to see how a lack of volcanic aerosols can warm the Earth. Back to you, Mr. R.

2. 252
Victor says:

249 jgnfld says:

“You defined a trend by reading 2 individual cherrypicked points off the graph. There is an obvious conclusion to be made here.”

I was not the one who defined that trend. It’s been duly noted by a great many climate scientists. You overestimate me, jg.

3. 253
Victor says:

247 MartinJB says:
7 Oct 2017 at 6:03 PM

“What’s generating the heat is energy from radiation from the sun (you know, sunlight). Aerosols reflect some of that radiation back into space, reducing the amount of energy entering the earth system. So, if lower volcanic activity during a period allows the concentrations aerosols to fall, more energy gets into the earth system, thus generating more heat. It’s that bloody simple.”

Not quite, though I appreciate the clarity of your explanation. What’s in question is not any rise in temperature produced by the dissipation of aerosols. I’ve already acknowledged that effect. What’s in question is the source of the runup in temperatures ca. 1910-1940. Since no amount of volcanic activity, either more OR less, can result in a rise in temperature greater than the level already present when the eruption (or lack of it) occurred, then the net result of any lack or slowdown of volcanic activity can never produce a persistent rise in temperature. At best, all it can do is return the temperature to the level that prevailed prior to some previous eruption (or group of eruptions). Thus the claim that a lack, or slowdown of volcanic activity could contribute in any meaningful way to the rise in temps. during that (or any) period is false.

Clear enough?

4. 254
MA Rodger says:

jgnfld @240,
What the troll is effectively saying @244 is:-
“The temperatures I cited were read directly off the graph I linked to. If you think you know more than the people who designed this graph, I urge you to direct your complaint to them.” He obtained his data from a graph on a New Scientist webpage which rebuts trolls like him, specifically ‘Climate myths: The cooling after 1940 shows CO2 does not cause warming’ By Catherine Brahic. You are expected to remember him citing this graph for a totally different reason up-thread @210. And as the source should be beyond reproach in your eyes, any problems you may have with his measuring of it are not down to him.
“If you’re attempting to minimize the importance of this early 20th century warming trend, I invite you also to make your case to the many climate scientists who have taken it very seriously and spent considerable time, effort and grant funding in their varied attempts to account for it. Here is one sample out of a great many that could be cited:-“ He is too stupid/lazy/dishonest to cherry-pick a recent paper examining the causes of early 20th century warming that would better suit his purpose. So do ignore the part of the quote he presents from Thompson et al (2014) which contradicts his argument. ““Of the rise in global atmospheric temperature over the past century, nearly 30% occurred between 1910 and 1940 when anthropogenic forcings were relatively weak.” (Victor is arguing for a 45% value, not the value below 30% presented by Thompson et al.) And likewise, do ignore the conclusions of Thompson et al:-

“Anthropogenic forcing was non-negligible during this time and probably contributed to warming. Increased solar output may have played a role in this accelerated warming as well, although the small rise in irradiance persisted from the start of the twentieth century to the 1950s, whereas the warming rate levelled off between 1940 and 1970. Similarly, a lack of strong volcanic eruptions between 1905 and 1961 may have contributed, but does not overlap uniquely with the war ming interval. Our data support a previously unrecognized role for internally generated Pacific trade-wind variability in contributing to the early twentieth-century warming, particularly before the mid-1920s.”

This, of course, invokes Anthro/Sol/Vol as drivers of the early 20th century warming and thus contradicts the troll but he is too is to stupid/lazy/dishonest to bother reading the paper he cites to check such things out, so ignore that part of the paper. For the troll, it is enough that it shows the early 20th century warming attribution still attracts research.

5. 255
jgnfld says:

@254 Yeah. But the thing, to me at least, that is so classic is defining “trends” by subtracting convenient local peaks and valleys from each other and ignoring all of the rest of the data as he does here. Deniers have been doing this forever. Some years ago tamino pointed out the complete mathematical absurdity of this on a number of occasions. But anyone (successfully) completing Stats 101 is aware of this as well.

For Vic’s edification should he care: Individual local peaks and valleys, you see, capitalize on chance more than using all values from the whole distribution does. That is why using them to define a trend across an interval is wrong. This is true regardless of whether you use annual values or 5 year running averages. You define a trend by looking at ALL the values together to see what they say.

You very argument show you at least implicitly understand this whether or not you do so explicitly. You see: Note that when you define warming in the early century you start from a local min and end at a local max. This capitalizes on chance to increase the apparent trend. Then you define modern warming starting from a local max and extending to the local min, as you say, just prior to the recent el Nino. This of course capitalizes on chance to reduce the apparent trend. You are using chance variations to come up with increased prior warming and decreased modern warming. This is called cherrypicking. If you aren’t aware you’ve fooled yourself–which I doubt–that is your problem. Anyone who can integrate e^x is capable of seeing it. And even many who cannot.

But in your defense, you are not the only denier to use such cherrypicking. Goddard is a past master to “cherrypick” just one exemplar.

As a more general comment, apparently Vic thinks his eyes do better at science than quantitative analysis. Besides his present math absurdity, remember waayyy back upthread when Vic was also doing correlations “by eye” that bore no relationship to what actual calculated correlations say?

6. 256
Victor says:

The many ad hominems and personal insults directed at me only weaken your case, folks. Real scientists avoid such language, and for good reason, because real scientists have real arguments to present and no need to blow smoke.

7. 257

Victor comes here to polish his sciency-sounding phrasing. Note the repeated iterations of similar spun claims.
We knock the rough edges off the claims for him, improving the way the words sound.
Once kind of shiny he uses the words elsewhere, benefiting from the patina of credibility he picks up by using words learned here.

“Reasoning will never make a Man correct an ill Opinion, which by Reasoning he never acquired” (Swift).

When our unrelenting troll tells us all what ‘science’ is, he’s telling us what it is to him: another way for him to fool himself. Whereas “the first rule [of science] is you must not fool yourself”, UT is determined to fool himself. Indeed, he’s long since fooled himself into robust denial of AGW.

Hank’s pithy analysis applies as well to the handful of other incorrigible AGW-deniers commenting on RC: they’re only here to polish their sciency-sounding phrasing. UT is both more tenacious and more prolix than the others, but they are all resolutely uninterested in correcting their ‘ill Opinions’.

One wouldn’t say any of their recent phrasing is more polished than when they first showed up, to be sure. Be that as it may, as previously noted the RC AGW-denier club serves to refute scurrilous ‘echo chamber’ accusations. Those of us who can’t resist explaining the same jaw-dropping errors over and over with slightly different words each time, are at worst stockpiling Op-Ed boilerplate ;^)!

8. 258
MA Rodger says:

Victor the Troll @304.
Consider the situation set before me. A prize numpty holds a belief with such confidence that up-thread (@238) he brands argument that contradict this belief as comprising a “logical fallacy” and that as the argument in question is “very simple” (which indeed it is), he is suggesting those contradicting this belief are either fools or rogues or both.
Then that same numpty, who makes a pig’s ear so often in setting out his arguments, in mis-referencing quotes and supporting data (when he could be bothered to provide references) and in mis-representing quotes and data; this same numpty in addressing me, describes a straightforward double-negative as “so damned convoluted it made me dizzy and prevented me from thinking straight.” He then sets out a ridiculous analogy for his belief and ends with the comment “Back to you, Mr R.”
So, charitably (me being “an incredibly charitable sort”, if you remember, Victor), let us consider the ‘ridiculous analogy’.

“(A) really large room contain(s) several air conditioners. Now if the air conditioners are turned on one at a time, each addition will contribute to the cooling of the room, obviously. But that is NOT the same as saying the room would warm up if NONE of the additional air conditioners were turned on. And obviously, it would not.”

(1) So if there are no operational air conditioners are ever “turned on” there will be none subsequently turned off and thus no resulting cooling, or warming. “Obviously!!”
But, Victor, there are air conditioners turned on. And then they are turn off, and when they are turned off the cooling will be reversed and that state is what experts term “warming.”
(2) And to complete the painful description of your ‘ridiculous analogy’, it is not that there are air conditioners being turned on and off infrequently, there are always air conditioners being turned on and turned off. The warming/cooling is dependent not on whether there are or are not air conditioners being turned on & off but how many are in operation now or have been in operation recently. If many become turned on there will be cooling, if the number becomes significantly fewer the cooling will be negative, which is a state experts call “warming”.
(3) And to snuff out the nonsensical assumption that underlies your ‘ridiculous analogy’, there is always an air conditioner on or recently on, such that the room never reaches the state you have described as (anagously) “the temperature … that prevailed prior to some previous air conditioner operation (or group of opertions).” As described in the Wigley et al (2006) quote which you mis-represented @234 (a mistake pointed out to you @239) “the temperature relaxes back toward the initial state (My bold) The “initial state” is that as modelled. Once the model begins to run, that “initial state” is approached but it is never ever achieved. Thus there is always some potential for what the experts call “warming” by reducing further the number of air conditioners in operation/recently in operation.

9. 259
Victor says:

From MA Rodgers latest screed, @ 254:

“He obtained his data from a graph on a New Scientist webpage which rebuts trolls like him, specifically ‘Climate myths: The cooling after 1940 shows CO2 does not cause warming’ By Catherine Brahic.”

That graph has been widely reproduced in many places, and no, I did not get it from that particular article.

However, since you mentioned it, the article you so kindly linked us to sends a mixed message. On the one hand it repeats the oft argued claim that the cooling after 1940 was largely due to sulfate aerosols produced by “industrial activities,” but on the other hand, she is honest enough to admit that “the situation is complicated” by factors rarely addressed by cli- change advocates:

“While aerosol emissions have fallen in Europe and the US (and in the former Soviet Union after 1991), they are now rising rapidly in China and India.

The picture is complicated because different kinds of aerosols can have different effects: black carbon or soot has warming rather than a cooling effect, for instance. Then there is the question of how all the different aerosols affect clouds. Climate scientists acknowledge that the aerosol issue is one of the key uncertainties in their understanding.”

Enuf said.

10. 260
MartinJB says:

Victor (@253): What you’ve been saying, ad-nauseam, is easy enough to understand, but it’s wrong. Honestly, you seem to get hung up trying to shoehorn the climate into a narrative construct using language that is ill-suited to our context here. I can’t see into your mind, but everything you write reads like you have a pretty quantitatively naive understanding of the physical world.

That said, in a trivial and largely irrelevant way, your assertions about how much impact a reduction in aerosol concentrations can have have some truth to them. But because of the way you seem to think about climate, you draw unjustified conclusions. Let me explain (and please, I welcome input and corrections from those who have more specific and detailed understanding of how this works!!!).

First, you get bogged down in this idea of the temperature before some eruption. Eruptions are always taking place. As Ray mentioned, they tend to follow a predictable distribution. Thus, over any long enough period of time, you can describe an average atmospheric aerosol concentration — as aerosols naturally leave the atmosphere, new ones are injected into it by ongoing eruptions. But, if there’s a particularly large eruption or the frequency of smaller eruptions increases there can be an extended deviation above the average (I think size on its own can matter more because of the altitude of injection?). Conversely, if over an extended period of time the frequency and/or size of eruptions declines then you can get a protracted deviation below the average. So, when looking at the impact of aerosols on temperatures, instead of thinking about some pre- or post-eruption state, it might help you to just think about longer-term changes or deviations from the average aerosol concentration resulting from changes in volcanic activity.

With that background, we can look at the impact of changing atmospheric aerosol concentrations. As you concede, reductions in aerosols (or deviations below the average) cause temperatures to increase. This is the transient response. Now, should the reduced concentration persist, more energy will continue to accumulate in the system until a new, higher equilibrium temperature is reached (the equilibrium response). In a trivial case, and if you really squint a lot, your argument has some resemblance to the equilibrium response. Absent other factors and positive feedbacks and ALL else equal, and I do mean ALL ELSE, there should be a particular equilibrium temperature for any given persistent concentration of aerosols.

But even in this trivial, non-physical case it is incorrect to assert (as you have on multiple occasions) that the impact of this cannot be meaningful. The impact is a function of the magnitude of the change in the concentration (i.e. deviation from the average) of aerosols. Large deviation —> larger impact, small deviation —> smaller impact. Similarly, the more protracted the state of reduced volcanic activity —> the larger and longer the reduction in aerosol concentrations —> the larger and more persistent the impact on temperatures. Not only do you (“you” as in Victor and not the general you, because I presume there are people who actually model these things and may know the answer) not know how large the equilibrium response would be, but you don’t know if the boundary proposed by your argument (cognate to the equilibrium response) had been reached over that period.

Also, note the caveat above: “Absent other factors and positive feedbacks and all else equal…” This is just as important, for all else is not equal. We know that there were two other factors at play, increasing CO2 and higher insolation, both of which also change the energy balance positively and therefore increase the equilibrium response to the changes in the environment. And then there are well-known positive feedbacks that further increase that temperature. All else is not remotely equal. That’s why we have multi-factor climate models.

So, your statement that “… the claim that a lack, or slowdown of volcanic activity could contribute in any meaningful way to the rise in temps. during that (or any) period is false” is unsupported.

Good lord, I wasted a lot of characters on this response that I am 99% sure will be futile, but I seem to be an incurable optimist. Anyway, it was useful for me to put a little more order to my thoughts…

11. 261
jgnfld says:

Vic-the-troll educates us on “real science” again stating “Real scientists avoid such language, and for good reason, because real scientists have real arguments to present and no need to blow smoke.”

Something tells me that Vic has never attended a “real science” meeting!!!

For your edification, Vic, actual real scientists have presented real information and arguments to you repeatedly here. You have persistently ignored them and continue to present completely sophomoric and utterly flawed ideas. Real scientists have no problem labeling idiotic drivel as drivel and the person presenting it as an idiot or a crank. Go to a scientific meeting and present your notions and see how long real scientists treat you with the dispassionate argumentation of your imagination. You will find reality a bit different from your imaginings. Persistent idiotic drivel simply does not promote dispassionate argumentation when important work is going on.

Here you get some slack as no one expects everyone who posts to exhibit a professional level of scientific education and so many try to reply with posts that do educate and explain. But you persistently ignore every bit of it.

Whether you realize it or not you have been treated pretty well here for someone presenting such volumes of idiotic drivel. Correlations “by eye”, naive thermodynamics sans math, and cherrypicking are just that. Idiotic drivel. If you tried this at a scientific meeting you would be instantly labeled as an idiot or crank and brushed off with quite “ad hominem” comments by “real scientists” should you persist. Most scientists have found by long experience that there is no other way to deal with a crank who refuses to listen and refuses to learn.

12. 262
Victor says:

In a perfect world, pedants like MARodger would eventually resist the temptation to continually mix nitpicks with ad hominems and actually make an effort to understand the point being made. Unfortunately the world we live in is all too imperfect, so Mr. Rodger will never understand that the present conversation is not about “Victor the troll,” but the effects of volcanic activity — and the lack of same. Whether or not I am an idiot as he’s been claiming since the dawn of time, matters not. What matters, in this instance, is whether or not a LACK of something can actually function as a CAUSE of something else.

The rebound effect in question is due to the dissipation of volcanic aerosols and NOT the lack of volcanic activity. And yes, if there were no lack of additional volcanic aerosols then the rebound would be delayed. Because actual volcanic activity CAN produce a real effect, while its absence cannot. And this is not a purely theoretical objection, or some sort of linguistic trick, as has been alleged, because the gist of the argument concerns our understanding, not simply of how we describe temperature rise, but the fundamental CAUSE of temperature rise.

Regarding my air conditioner analogy, Rodger predictably falls into the trap I assumed he’d fall into, as he consistently prefers nitpicking to actual understanding. For his benefit, and those of you who still don’t get it, let me make my analogy as precise as I possibly can. It shouldn’t be necessary since the point should have been crystal clear from the start, but this is an unusual situation, where confirmation bias runs riot over critical thinking, to the detriment of meaningful debate.

OK, we have a large room containing several air conditioners. All are turned on and the room cools. After a certain time, the others are turned off one by one until only the original a.c. is still on. As should be obvious, the lack of cooling from the air conditioners that have been turned off cannot possibly add any more heat to the room. That does NOT mean the room won’t necessarily get warmer, but if it does it will be due to conditions outside the room, NOT to the lack of cooling from the turned off air conditioners. We can also visualize a situation where the room actually gets cooler due to the outer environment cooling down. If that happens, it should be especially obvious that any absence of cooling from the turned off air conditioners will not add any warmth to that room.

When I’m reminded that the Earth’s atmosphere is far more complicated than the analogy I’ve just made, I can only agree. But the presence of factors other than the lack of volcanic aerosols is directly analogous to the condition of the external environment in the air conditioned room. Once all aerosols dissipate (equivalent to what will happen as all the additional air conditioners are shut off), then the lack of any additional aerosols cannot possibly have a warming effect, any more than the lack of cooling from the additional air conditioners can have a warming effect.

NOW do you get it? (Probably not, very sadly.)

13. 263
nigelj says:

Victor for the tenth time, look up a basic dictionary definition of warming. Its a change in temperature, a very simple thing, not heat energy as such. This is why you are confused and at cross purposes with everyone, you dont even understand the most basic of definitions.

I can see at a glance what other people here are saying is sensible enough while I can see at a glance you are totally wrong.

And while some affects of aerosols are not certain the effects of volcanic aerosols are very certain. Temperatures drop sharply for a year or two as regular as clockwork and in proportion to the explosion.And the causal mechanism is well understood.

Here’s some advice: Stop acting like a fool. When I’m wrong I admit it and move on, I don’t dig myself into ever deeper holes like you are doing and that everyone can see. You remind me of Basil Fawlty in the television programme fawlty towers.

However I’m not often wrong. Note how nobody ever defends you even other sceptics. They wont defend the indefensible.

14. 264
nigelj says:

Martin JB @260 yes exactly right. You have a fairly regular pattern of volcanic explosions over time but it varies for short periods and it did this early last century. Its obvious stuff.

But Victor doesnt want to understand this. He is determined that something mysterious and unknown is causing recent climate change so as part of this he has to deny all prior forms of climate change including aerosols, CO2, solar etc. Its hilarious. Occams razor says the simplest explanation is mostly correct and we have a couple of simple explanations and well proven ones, so we dont have to invoke something mysterious and vanishingly unlikely.

Victor is like a self righteous teenager never, ever prepared to admit he is wrong. I was like that once, but I grew up and developed some sense.

15. 265
MA Rodger says:

jgnfld @255,
It is true that normal people would agree that some manner of calculated trend is infinately preferable to somebody poking a grubby finger at convenient maxima or minima. But importantly those are “normal people.” Victor the Troll is evidently both stupid and struggling against AGW denial. (You can blame the internet for this, giving scurrilous agents access to his impressionable mind.) His disconnect from reality is so great that he, brainless Victor, actually felt qualified enough on the subject to write a book refuting the existence of AGW!!

But if you do wish to reach out to poor Victor, keep your message very short-&-simple as you will note that he only pays attention at the begining of a comments and goes quickly defensive. Any take-away message after that first paragraph will potentially go unread by him. And if the content of that first paragraph proves too much for the trolls limited abilities (like the double-negative @235) or too challenging for his worldview, any message anywhere in your comment will properly not be grasped.
Observe @259, he responds to #254 but does no more than say “It wanny me!!” because he hadn’t visited that New Scientist page (and this is true – he got no further than the first image from the simplest of google searches) but that now he has sight of the webpage he can misrepresent the content of that as well.
@253 he responds to #244 which is not much more than a single paragaph and proved remarkably productive (so ‘Well done!!’ MartinJB). Okay the troll ends up repeating his own stupidity because he didn’t properly absorbed the message being presented but it did get him articulating that his blather down this thread is so much bullshit. Unfortunately poor Victor has yet to notice the implications of his words – “What’s in question is not any rise in temperature produced by the dissipation of aerosols. I’ve already acknowledged that effect.”
@252 he responds to #249, another short comment. His response is to blame the scientists because trends are beyond his comprehension. “You overestimate me, jg.”
And @251 he responds to the short #244 by re-visiting #235 but only addresses the first sentence @235. (This is pretty-much what he managed when he first addressed #235 with his comment @238, although he does excuse his ignoring the bulk of #235 saying “we could go on and on quibbling over all the various ins and outs, but as far as I’m concerned I’ve made the essential points,” which he then trots out with added error just in case anybody missed it before.)
So, remember when adressing Victor the Troll – “normal people” naturally take on board the reason for a comment having a second or third or fourth paragraph, that the commenter’s message requires you to read those paragraphs and understand what is being said. With Victor, if he manages to grasp the meaning of just the first paragraph, he is still quickly off and away with his denialism and the content of your comment he did momentaraly grasp is soon forgotten.

16. 266

Been trolled again, apparently. Victor is provocative, I’ll give him that much.

OK. Per #251:

To understand the flaw in this reasoning, let’s once again consider an air conditioned room. Only this time it’s a really large room containing several air conditioners. Now if the air conditioners are turned on one at a time, each addition will contribute to the cooling of the room, obviously. But that is NOT the same as saying the room would warm up if NONE of the additional air conditioners were turned on. And obviously, it would not.

Once again, we have a thought experiment in which some necessary parameters are undefined.

To wit: if the outside temperature is -40 degrees, then no, failing to turn on any number of air conditioners would not result in warming. If, however, it is 40 C, then failing to turn them on will do so in short order.

I hear a distant, tiny voice exclaiming in dismay that no, the warming is not due to the lack of air conditioning, but to the high temperature outside. There may be some sense in which that is true, but it is not very helpful to the unfortunate inhabitant(s) of said room*–nor is it a very satisfactory perspective in terms of modeling heat fluxes in and out of the room.

To do that, you’d quantify the cooling effect of the air conditioner as well as the heating effect of the warm outside environment, plus any other relevant factors–who knows, maybe someone is baking bread in there or something–and you’d do your sums. Get it all right, and you’d be able to pretty accurately predict room temperature under all manner of scenarios for outside temperature change, air conditioner use, and completion of the batch of bread.

Which, as far as I can tell, is (analogously) what Real Scientists actually do in the case of the Real World.

Contrariwise, they *don’t* get hung up on sterile quasi-Platonic debates about verbal formulations.

*NB.–For us this summer, the ‘air conditioner experiment’ was not actually a ‘thought experiment.’ In the true spirit of empiricism, I’m pleased to report that running the air conditioner indeed cooled the room. Every damn time we broke down and used it, actually. Ain’t science wonderful!

And I fail to see anything wrong with the statement that ‘the room warmed up if we didn’t turn on the AC.’

‘Cause it sure as hell did… every damn time, actually.

17. 267
MA Rodger says:

Perhaps we are almost there. As I remember, the Apostle Peter denied Our Lord thrice followed by a teary realisation. “Then the cock crew for a second time and Peter remembered how Jesus had said to him ‘ Before the cock crows twice you will deny me three times.” And he burst into tears.” Mark 15:72.

Victor the Troll @262.
Your denial becomes more obvious to all-but-you by the day. In you latest offering @262, you are providing two separate issues of nonsensical denial.

Firstly you say “If there were no lack of additional volcanic aerosols then the rebound would be delayed. Because actual volcanic activity CAN produce a real effect, while its absence cannot.” Goodness!! “no lack”! I spy with my little eye a “double negative”!! Yet, while on this occasion such a logical construct does not cause problems, the logic presented is flawed through-&-through.
Victor, if an absence of volcanic aerosols results from their “dissipation” and this in turn results in a “rebound” as you say it does, is not such a “rebound” a “real effect” resulting from an “absence” (or more usually a partial absence) of volcanic aerosols? Note this analogy – this is not saying that the fairies at the end of your garden are responsible for anything real happening (like smashing your garden fence down). In the analogy the real happening is because these fairies are real and absent. It is their absenting themselves that made the ‘real happening’ happen, they being no longer there having made a big big mess as they exited over your garden fence.

Secondly, in your analogy, you tell us “That does NOT mean the room won’t necessarily get warmer, but if it does it will be due to conditions outside the room, NOT to the lack of cooling from the turned off air conditioners.” (Note that these are “turned off air conditioners” and not ones that have not been turned-on-&-operating recently. [Ooops!! A double-negative, adding to Victor’s own “does NOT … won’t”!!!])
Certainly the net energy flow warming the room will originate from “outside the room” but the enabling factor that has so far prevented that net energy flow from warming the room was the air conditioners sucking energy out of the room. It is the change in net energy flow that is the reason for the warming and that change is due to the air conditioners being recently switched off. (I suppose that is a bit like additional CO2 switching off parts of the energy flow from the planet surface out into space, a process often called AGW. So, “Danger, Will Robinson!” Our troll could be on the verge of blaming AGW on the sun! Or even the temperature of space!!)

18. 268
Victor says:

[edit – enough. This is too tedious for words]

19. 269

Gavin said: “[edit – enough. This is too tedious for words]”

To which I can only add, ‘and the conversation couldn’t have been carried out using numbers.’ For some levels of absurdity, only natural language will do.

20. 270
21. 271
Hank Roberts says:

It’s unusual to have such extreme fire weather at night, said UC Berkeley Professor Scott Stephens, who specializes in fire science. Temperatures typically drop after the sun goes down. That makes the land more moist, because cold air holds less water.

But that has changed somewhat in California over the last 15 years, Stephens said. Overnight lows are rising, so the air stays drier after dusk. One result, he said, is that night fires are much more common.

I’m pretty sure this is the scientist I heard on local KQED radio today, who started to talk about climate change — he got as far as saying he’d been teaching his students about climate change including this for years, and the fire problem is going to get much worse — and then the radio host cut him off.

22. 272
jgnfld says:

@271 “he got as far as saying he’d been teaching his students about climate change including this for years, and the fire problem is going to get much worse — and then the radio host cut him off.”

Come on now Hank. During a fire is not the time to talk about climate change. We can only talk about climate change when there are precisely zero sequelae from climate change occurring. To talk about it now during a fire–or whenever the sea is rising or the global temperature trends are rising or the global seas are warming–is just sheer “alarmism”.

23. 273

#270, Hank–LOL.

And ‘exactly.’

24. 274
mike says:

HR at 271 0: you are so right to notice and comment on how the media frames the discussion to prevent or reduce discussion of global warming and climate change. The NPR and PBS system is no better than the others.

25. 275

I’m pretty sure this is the scientist I heard on local KQED radio today, who started to talk about climate change — he got as far as saying he’d been teaching his students about climate change including this for years, and the fire problem is going to get much worse — and then the radio host cut him off.

KQED, of course, is an NPR/PBS member station. The American plutocracy and its political division the Republican Party are, of course, hostile to public funding for NPR and PBS. As of last May, Trump’s proposed budget eliminates funding for the Corporation for Public Broadcasting:

“The Budget proposes to eliminate Federal funding for the Corporation for Public Broadcasting (CPB). CPB grants represent a small share of the total funding for the Public Broadcasting Service (PBS) and National Public Radio (NPR), which primarily rely on private donations to fund their operations. To conduct an orderly closeout of Federal funding, the Budget requests \$30 million, which includes funding for personnel costs of \$16.2 million, rental costs of \$8.9 million, and other costs totaling \$5.4 million.”

So, it appears political appeasement may not save public funding in public media’s time. That leaves it in the hands of private sponsors. What’s the point?

That said, one presumes the AGW-denial industry can generate a lot of ‘public’ feedback to any mention of AGW in public media.

26. 276
Victor says:

[edit – enough. This is too tedious for words]

I can’t complain, because you are right. This dispute could go on forever, and this is as good a place to cut if off as any.

I’ve made my point in any case. Thanks for your patience, Gavin.

27. 277

“So, it appears political appeasement may not save public funding in public media’s time. That leaves it in the hands of private sponsors. What’s the point?”

Maybe that one of those private sponsors is Koch Industries, who are currently using underwriting spots to try to greenwash their image with crap about their devotion to ‘renewable fuels’, whatever that is supposed to mean.

Don’t get me wrong; I listen to lots of NPR, and have supported them for years. And while I’m not satisfied with their coverage of climate change, at least there *is* coverage of climate change on their shows. But I really, really don’t like to hear those Koch spots; the Kochs have bought enough of this country’s politics and culture already.