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The Non-linearity of Global Temperature Changes

Jack Hays

Jack Hays

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Perhaps the climate gods have a sense of humor. The propaganda graphic used by Skeptical Science against climate skeptics may, in fact, be an accurate representation of temperature change.

Climate Models / Climate sensitivity
A ground-breaking new paper putting climate models to the test yields an unexpected result – steps and pauses in the climate signal

A ground-breaking new paper has recently been published in Earth System Dynamics that really turns the idea of direct linear warming of the atmosphere on it’s ear, suggesting a “store and release mechanism” by the oceans, which explains why there seemed to be a shift in global temperature during the 1997/98 super El Nino followed by a “pause” in global temperatures.
Remember the “escalator” graph from wrongly named “Skeptcal Science” designed to shame climate skeptics? Looks like that may have been an accidentally prescient backfire on their part based on the findings of this new paper.

The paper is: “Reconciling the signal and noise of atmospheric warming on decadal timescales“, Roger N. Jones and James H. Ricketts, Earth System Dynamics, 8 (1), 2017.
Abstract:
“Interactions between externally forced and internally generated climate variations on decadal timescales is a major determinant of changing climate risk. Severe testing is applied to observed global and regional surface and satellite temperatures and modelled surface temperatures to determine whether these interactions are independent, as in the traditional signal-to-noise model, or whether they interact, resulting in step-like warming.
“The multistep bivariate test is used to detect step changes in temperature data. The resulting data are then subject to six tests designed to distinguish between the two statistical hypotheses, hstep and htrend.
Test 1: since the mid-20th century, most observed warming has taken place in four events: in 1979/80 and 1997/98 at the global scale, 1988/89 in the Northern Hemisphere and 1968–70 in the Southern Hemisphere. Temperature is more step-like than trend-like on a regional basis. Satellite temperature is more step-like than surface temperature. Warming from internal trends is less than 40 % of the total for four of five global records tested (1880–2013/14).
Test 2: correlations between step-change frequency in observations and models (1880–2005) are 0.32 (CMIP3) and 0.34 (CMIP5). For the period 1950–2005, grouping selected events (1963/64, 1968–70, 1976/77, 1979/80, 1987/88 and 1996–98), the correlation increases to 0.78.
Test 3: steps and shifts (steps minus internal trends) from a 107-member climate model ensemble (2006–2095) explain total warming and equilibrium climate sensitivity better than internal trends.
Test 4: in three regions tested, the change between stationary and non-stationary temperatures is step-like and attributable to external forcing.
Test 5: step-like changes are also present in tide gauge observations, rainfall, ocean heat content and related variables.
Test 6: across a selection of tests, a simple stepladder model better represents the internal structures of warming than a simple trend, providing strong evidence that the climate system is exhibiting complex system behaviour on decadal timescales.
“This model indicates that in situ warming of the atmosphere does not occur; instead, a store-and-release mechanism from the ocean to the atmosphere is proposed. It is physically plausible and theoretically sound. The presence of step-like – rather than gradual – warming is important information for characterising and managing future climate risk.”
​

 
Any chance of a translation?

I mean the idea that temperatures are stepping up rather than being a smooth curve is slightly interesting but I don't see it as significant.
 
Tim the plumber said:
Any chance of a translation?

I mean the idea that temperatures are stepping up rather than being a smooth curve is slightly interesting but I don't see it as significant.
Click to expand...

I'd guess that it's potentially good news, if true. 10 to 15 years could be several generations for many species, a time in which instead of steadily-increasing pressure there might be a little more opportunity to adapt to the newer conditions before the next big hit. (Thinking of corals specifically here, where major bleaching events can cause mass die-offs, so the only hope of maintaining their extent or even avoiding possible extinctions is for the toughest survivors to have the time to repopulate.) Whether the hypothesis is correct is one question, and whether it would be enough to make any real difference is another.
 
Mithrae said:
I'd guess that it's potentially good news, if true. 10 to 15 years could be several generations for many species, a time in which instead of steadily-increasing pressure there might be a little more opportunity to adapt to the newer conditions before the next big hit. (Thinking of corals specifically here, where major bleaching events can cause mass die-offs, so the only hope of maintaining their extent or even avoiding possible extinctions is for the toughest survivors to have the time to repopulate.) Whether the hypothesis is correct is one question, and whether it would be enough to make any real difference is another.
Click to expand...

Given that the biggest step is less than 0.2c I don't see the changes as especially savage compaired to tyhe normal variation in temperature from day to day or year to year.
 
Tim the plumber said:
Given that the biggest step is less than 0.2c I don't see the changes as especially savage compaired to tyhe normal variation in temperature from day to day or year to year.
Click to expand...

I know you don't, purely because (as we've seen many times before) you simply don't want to see it and actively refuse to do so even when the facts are repeatedly pointed out to you.

IPCC AR5 WG1 Chapter 6, Box 6.1
Major bleaching events were observed in 1982-83, 1987-88 and 1994-95 (Hoegh-Guldberg, 1999). Particularly severe bleaching occurred in 1998 (Figure 6.2), associated with pronounced El Niño events in one of the hottest years on record (Lough, 2000; Bruno et al., 2001). Since 1998 there have been several extensive bleaching events. For example, in 2002 bleaching occurred on much of the Great Barrier Reef (Berkelmans et al., 2004; see Chapter 11, Section 11.6) and elsewhere. Reefs in the eastern Caribbean experienced a massive bleaching event in late 2005, another of the hottest years on record. On many Caribbean reefs, bleaching exceeded that of 1998 in both extent and mortality (Figure 6.2), and reefs are in decline as a result of the synergistic effects of multiple stresses (Gardner et al., 2005; McWilliams et al., 2005; see Box 16.2). There is considerable variability in coral susceptibility and recovery to elevated SST in both time and space, and in the incidence of mortality (Webster et al., 1999; Wilkinson, 2002; Obura, 2005).​

Great Barrier Reef coral bleaching could be the new normal by 2050, research finds | Australian Broadcasting Corporation
The sea surface temperatures on the Great Barrier Reef were the hottest on record during February, March and April last year — a degree or more above the long-term monthly averages.

The resulting coral die-off was the largest ever recorded on the Great Barrier Reef, with about two-thirds of corals dying in the 700 kilometres north of Port Douglas in far north Queensland.

If emissions are not cut significantly and quickly, then temperatures like March 2016 are likely to become very common by the 2030s and 2040s, according to Dr Andrew King, a climate scientist from the University of Melbourne who led the research.​
 
Yes, a full 1 degree causes the corrals to bleach. They then recover quickly. This is what they do when there is an unseasonal weather event.

Given that coral keeps working at much higher temperatures, with probably different particular species in there, why do I have to panic about a 0.2c rise when they can recover from a +1c event quickly?
 
...this doesn't invalidate the point of skeptical science.
 
Jack Hays said:
Except that it argues the "contrarian" (SS's term) view of global warming is the accurate one.
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No, it doesn't. You've interpreted that illustration as saying "contrarians believe the earth's temperature rises in steps." This is not an accurate perception.
 
Deuce said:
No, it doesn't. You've interpreted that illustration as saying "contrarians believe the earth's temperature rises in steps." This is not an accurate perception.
Click to expand...

I don't resume to speak for contrarians but Skeptical Science did, and said so explicitly. No one to blame for this embarrassment but SS themselves.:lol:
 
Jack Hays said:
I don't resume to speak for contrarians but Skeptical Science did, and said so explicitly. No one to blame for this embarrassment but SS themselves.:lol:
Click to expand...

Your perception of that illustration is wrong.

The correct perception is: "Contrarians are looking at one of these steps as evidence the planet has stopped getting warmer, but here's a bigger picture showing that this 'step' setup is normal."

You have it backwards: with this article, suddenly "contrarians" are accepting the "step climb" model.

I hope this helps your confusion.

"Direct linear warning" was never actually the prediction. I know it might look that way to a layman, but it's really not correct.
 
Jack Hays said:
Perhaps the climate gods have a sense of humor. The propaganda graphic used by Skeptical Science against climate skeptics may, in fact, be an accurate representation of temperature change.
Click to expand...

Deuce said:
Your perception of that illustration is wrong.
Click to expand...

It does appear that your perception and/or characterization of the Skepticalscience.com page is incorrect.

Here is the original page for your reference: The Escalator

The main point of the illustration is to show how 'cherrypicking' of short term data can show a short-term decreasing trend in temperatures, even though the long term trend is upward. The article has nothing whatsoever to do with 'plateaus'.

Would you agree?

Does it bother you at all that whatsupwiththat got it wrong by saying that: "Remember the “escalator” graph from wrongly named “Skeptcal Science” designed to shame climate skeptics? Looks like that may have been an accidentally prescient backfire on their part based on the findings of this new paper."?

Why not?
 
Deuce said:
Your perception of that illustration is wrong.

The correct perception is: "Contrarians are looking at one of these steps as evidence the planet has stopped getting warmer, but here's a bigger picture showing that this 'step' setup is normal."

You have it backwards: with this article, suddenly "contrarians" are accepting the "step climb" model.

I hope this helps your confusion.

"Direct linear warning" was never actually the prediction. I know it might look that way to a layman, but it's really not correct.
Click to expand...

What a breathtakingly deceitful post. You are quite presumptuous about what contrarians believe, and in any case that is not what Skeptical Science routinely placed as their caption to the graphic. The SS "step climb" model was routinely accompanied by the "consensus" graphic showing just such direct, linear warming, every time.
 
Jack Hays said:
What a breathtakingly deceitful post. You are quite presumptuous about what contrarians believe, and in any case that is not what Skeptical Science routinely placed as their caption to the graphic. The SS "step climb" model was routinely accompanied by the "consensus" graphic showing just such direct, linear warming, every time.
Click to expand...

You are presumptuous about what skeptical science is saying contrarians believe.

That line wasn't showing "direct linear warming." That was a trend line. I'm not sure you understand what that means.
 
Deuce said:
You are presumptuous about what skeptical science is saying contrarians believe.

That line wasn't showing "direct linear warming." That was a trend line. I'm not sure you understand what that means.
Click to expand...

Just more dodging.
 
Jack Hays said:
Just more dodging.
Click to expand...

It's not.

Drawing a straight line to show a trend isn't the same thing as "direct linear warming."

The purpose of that illustration is "you can miss the overall trend if you use only short timeframes. See, here's a bunch of mathematically accurate 'flat trends' but obviously the trend across this whole century is an increase in temperature."

Does it make sense to you now?
 
Deuce said:
It's not.

Drawing a straight line to show a trend isn't the same thing as "direct linear warming."

The purpose of that illustration is "you can miss the overall trend if you use only short timeframes. See, here's a bunch of mathematically accurate 'flat trends' but obviously the trend across this whole century is an increase in temperature."

Does it make sense to you now?
Click to expand...

That explanation might have been persuasive had it been offered at the time. Now, it looks like a Johnny-come-lately rationalization. No sale.
 
Jack Hays said:
That explanation might have been persuasive had it been offered at the time. Now, it looks like a Johnny-come-lately rationalization. No sale.
Click to expand...

I'm sorry, Jack, but statistics has always worked this way.

Seems to me you're doing whatever it takes to internally justify such a ludicrous claim as the OP article is making.
 
You want proof, Jack?

Here's an article that image appears in:

https://www.skepticalscience.com/global-cooling-january-2007-to-january-2008.htm

To find out whether there is actually a 'cooling trend,' it is important to consider all of these claims as a whole, since they follow the same pattern. In making these claims, skeptics cherrypick short periods of time, usually about 20 years or less.
Click to expand...

Below is the same temperature chart, showing how skeptics manipulate the data to give the impression of 'Global Cooling'. First they choose the warmest most recent year they can find. Then, in this case, they exclude 20 years of previous temperature records. Next they draw a line from the warmest year (the high peak) to the lowest La Niña they can find. In doing this they falsely give the impression that an ordinary La Niña is actually a cooling trend.
Click to expand...

In spite of these facts, skeptics simply keep changing their dates for 'Global Cooling', constantly confusing short-term noise and long-term trends (Figure 4).
Click to expand...

So there it is. Clear, undeniable proof that the image in question is discussing cherry picking short trends.
 
Deuce said:
I'm sorry, Jack, but statistics has always worked this way.

Seems to me you're doing whatever it takes to internally justify such a ludicrous claim as the OP article is making.
Click to expand...

Not at all. SS offered the contrast as a straight-up "reality vs deniers" comparison. Too late now to say they didn't mean it.
 
Threegoofs said:
It's pretty clear that this is just trolling now.

No one who has spent any time at all looking at this data could believe this ridiculousness.
Click to expand...

To be fair, I don't think that it is just trolling. The fact that even the tropospheric temperature records now show an end to 'the pause' marks the demise of contrarians' single best talking point. I know that some others have disputed it, but I for one generally acknowledged the presence of a 'pause' in the temperature records, misleading though contrarians' rhetoric about it may have been.

If it's something that a fellow like me acknowledges (see some of the comments Jack and Flogger have made about me :roll: ), 'the pause' was undeniably one of the best talking points available to contrarians. Both this and the solar thread which Jack has recently started seem to be attempts to come to terms with that loss.
 
Mithrae said:
To be fair, I don't think that it is just trolling. The fact that even the tropospheric temperature records now show an end to 'the pause' marks the demise of contrarians' single best talking point. I know that some others have disputed it, but I for one generally acknowledged the presence of a 'pause' in the temperature records, misleading though contrarians' rhetoric about it may have been.

If it's something that a fellow like me acknowledges (see some of the comments Jack and Flogger have made about me :roll: ), 'the pause' was undeniably one of the best talking points available to contrarians. Both this and the solar thread which Jack has recently started seem to be attempts to come to terms with that loss.
Click to expand...

I really do think it's trolling.

Even passing familiarity with temperature records tells you you'll never see a perfectly linear rise or fall - and the argument here is that since variability exists, the 'escalator' is actually a real thing.

This misses the obvious point that the 'escalator' is pointing out the basic disingenuousness of deniers - harping upon short term trends that bolster their denial and ignoring/dismissing trends that are counterpoints.
 
Threegoofs said:
I really do think it's trolling.

Even passing familiarity with temperature records tells you you'll never see a perfectly linear rise or fall - and the argument here is that since variability exists, the 'escalator' is actually a real thing.

This misses the obvious point that the 'escalator' is pointing out the basic disingenuousness of deniers - harping upon short term trends that bolster their denial and ignoring/dismissing trends that are counterpoints.
Click to expand...

Well, it obviously has been asserted by many contrarians in the past that global warming had halted, and as Deuce has pointed out the SS escalator graphic was intended to point out the irrationality and ultimately dishonesty of such 'reasoning.'

But that doesn't mean that there is no mechanism of oceanic storage/release which might produce such results (with varying degrees of consistency; there's no similar 'pause' in the 80s or 90s for example). The paper in question - at least as far it's described in the OP - seems to be based primarily on statistical analysis which I don't find particularly compelling, but A) that doesn't mean it's wrong and B) such a mechanism has been proposed in the past to explain the 'hiatus' (Trenberth and Fasullo 2013 is an example of that, I suspect).

But again, even Jack's attempt to re-appropriate such scientific results in terms of contrarian rhetoric is not trolling, in the sense of merely trying to irritate/provoke a response - the undeniable end to what was undeniably contrarians' best talking point is a serious issue.
 
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Threegoofs said:
I really do think it's trolling.

Even passing familiarity with temperature records tells you you'll never see a perfectly linear rise or fall - and the argument here is that since variability exists, the 'escalator' is actually a real thing.

This misses the obvious point that the 'escalator' is pointing out the basic disingenuousness of deniers - harping upon short term trends that bolster their denial and ignoring/dismissing trends that are counterpoints.
Click to expand...

Mithrae said:
Well, it obviously has been asserted by many contrarians in the past that global warming had halted, and as Deuce has pointed out the SS escalator graphic was intended to point out the irrationality and ultimately dishonesty of such 'reasoning.'

But that doesn't mean that there is no mechanism of oceanic storage/release which might produce such results (with varying degrees of consistency; there's no similar 'pause' in the 80s or 90s for example). The paper in question - at least as far it's described in the OP - seems to be based primarily on statistical analysis which I don't find particularly compelling, but A) that doesn't mean it's wrong and B) such a mechanism has been proposed in the past to explain the 'hiatus' (Trenberth and Fasullo 2013 is an example of that, I suspect).

But again, even Jack's attempt to re-appropriate such scientific results in terms of contrarian rhetoric is not trolling, in the sense of merely trying to irritate/provoke a response - the undeniable end to what was undeniably contrarians' best talking point is a serious issue.
Click to expand...


[h=1]How Imminent is the RSS Pause? (Now Includes January and February Data)[/h]Guest Post by Werner Brozek, Extended Comments from Barry and Edited by Just The Facts UAH (University of Alabama in Huntsville) and RSS (Remote Sensing Systems) are two major satellite groups that provide monthly climate anomalies. From January 1998 to January 2016, the slope was slightly negative, a period which many have referred to as…

March 14, 2017 in Global Temperature Update.
[h=1]How Imminent is the UAH Pause? (Now Includes Some January Data)[/h]Guest Post by Werner Brozek, Excerpts from Barry and Edited by Just The Facts At Dr. Roy Spencer’s site, regular commenter Barry posted seven very interesting comments, begining here, with respect to the requirements for the UAH pause to resume. He has graciously allowed me to use whatever I wished in this blog post. Everything that…

February 19, 2017 in Climate News, Global Temperature Update.
 
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