Commentary from Nature Climate Change, by John C. Fyfe, Nathan P. Gillett, & Francis W. Zwiers
Recent observed global warming is significantly less than that simulated by climate models. This difference might be explained by some combination of errors in external forcing, model response and internal climate variability.
Global mean surface temperature over the past 20 years (1993–2012) rose at a rate of 0.14 ± 0.06 °C per decade (95% confidence interval)1. This rate of warming is significantly slower than that simulated by the climate models participating in Phase 5 of the Coupled Model Intercomparison Project (CMIP5). To illustrate this, we considered trends in global mean surface temperature computed from 117 simulations of the climate by 37 CMIP5
models (see Supplementary Information).
These models generally simulate natural variability — including that associated
with the El Niño–Southern Oscillation and explosive volcanic eruptions — as
well as estimate the combined response of climate to changes in greenhouse gas
concentrations, aerosol abundance (of sulphate, black carbon and organic carbon,
for example), ozone concentrations (tropospheric and stratospheric), land
use (for example, deforestation) and solar variability. By averaging simulated
temperatures only at locations where corresponding observations exist, we find
an average simulated rise in global mean surface temperature of 0.30 ± 0.02 °C
per decade (using 95% confidence intervals on the model average). The
observed rate of warming given above is less than half of this simulated rate, and
only a few simulations provide warming trends within the range of observational
uncertainty (Fig. 1a).
Figure 1 | Trends in global mean surface temperature. a, 1993–2012. b, 1998–2012. Histograms of observed trends (red hatching) are from 100 reconstructions of the HadCRUT4 dataset1. Histograms of model trends (grey bars) are based on 117 simulations of the models, and black curves are smoothed versions of the model trends. The ranges of observed trends reflect observational uncertainty, whereas the ranges of model trends reflect forcing uncertainty, as well as differences in individual model responses to external forcings and uncertainty arising from internal climate variability.
The inconsistency between observed and simulated global warming is even more
striking for temperature trends computed over the past fifteen years (1998–2012).
For this period, the observed trend of 0.05 ± 0.08 °C per decade is more than four
times smaller than the average simulated trend of 0.21 ± 0.03 °C per decade (Fig. 1b).
It is worth noting that the observed trend over this period — not significantly
different from zero — suggests a temporary ‘hiatus’ in global warming. The
divergence between observed and CMIP5-simulated global warming begins in the
early 1990s, as can be seen when comparing observed and simulated running trends
from 1970–2012 (Fig. 2a and 2b for 20-year and 15-year running trends, respectively).
The evidence, therefore, indicates that the current generation of climate models
(when run as a group, with the CMIP5 prescribed forcings) do not reproduce
the observed global warming over the past 20 years, or the slowdown in global
warming over the past fifteen years.
This interpretation is supported by statistical tests of the null hypothesis that the
observed and model mean trends are equal, assuming that either: (1) the models are
exchangeable with each other (that is, the ‘truth plus error’ view); or (2) the models
are exchangeable with each other and with the observations (see Supplementary
Information).
Brief: http://www.pacificclimate.org/sites/default/files/publications/pcic_science_brief_FGZ.pdf
Paper at NCC: http://www.nature.com/nclimate/journal/v3/n9/full/nclimate1972.html?WT.ec_id=NCLIMATE-201309
- Supplementary Information (241 KB) CMIP5 Models
steveta_uk says:
September 5, 2013 at 3:46 am
This is also a completely different experiment. Light energy that isn’t absorbed at the surface will warm the bottom of the bowl and then heat the water. (In the ocean some will be absorbed by water and stuff in it.) Of course, there’s the claim that visible light doesn’t heat objects, only infrared does that, probably the most blatantly idiotic claim.
Good place to start the numbers from, 1993 at the deepest part of the temp downturn from the Pinatubo eruption. One gets the max temp increase trend starting here.
To be fair, the authors then go on to remove the volcanic and ENSO signals and find less warming of course. Then they note the temp trends are similar to the AMO cycles.
At least the climate scientists are no longer ignoring the difference between the models and the observations.
A lot of you are noting and criticizing the paper for noting the hiatus to be “temporary.” But I would just like to point out that this is a huge step for some climate scientists, to acknowledge that the data does in fact point out that the rate of warming is not statistically significant from zero over the last 15 years. We’re making baby steps. At first there was vehement denial that such a pause existed, and many that acknowledged it were chastised. Now, we are getting “mainstream” confirmation, which IMO is huge. This is also considering that the 1990s saw some pretty quick rates of warming. Even including that rate, the models still grossly overestimate temperature rise.
Rich says:
September 5, 2013 at 1:18 am
“This difference might be explained by … internal climate variability.” Surely if you’re modeling the climate you can’t say, “My model’s wrong because of internal climate variability” because that’s exactly what you’re supposed to be modeling. They keep saying this and I don’t get it.
RICH, I do not think the modelers and their enablers are capable of admitting that “maybe the models are wrong” because
a. They want the money to keep flowing
b. The models have become articles of faith, rather than tools for exploring the science
gnomish said on September 5, 2013 at 2:59 am:
Proposed: Thermal radiation from an infrared heater applied to the surface of water cannot heat the water.
Experiment setup:
1 bowl of unknown plastic, semi-flexible, no recycling symbol indicating plastic type, 2 1/3 cups (US measure) capacity. Approximate dimensions: 5 1/2″ inside diameter top with 1/2″ wide rim, 2″ effective depth, circular arc curve (concave interior surface) to 2 7/8″ diameter flat bottom, with integral hollow cylindrical section base of 1/4″ height and 2 7/8″ diameter. Base design minimizes heat transfer with surface underneath. Usually used for cold to warm contents (ice cream to oatmeal) but not boiling hot items.
1 Master Forge Wireless Thermometer #0023557, originally purchased at Lowes, consists of display-less transmitting base with probe and receiving hand unit which displays temperature, set for °F. Normally used for grilling/roasting. Has timer count-up and count-down functions displaying minutes and seconds. Used for temperature readings and timing.
2 cups (US measure) room temperature tap water, from well.
1 Sears Kenmore 30″ Electric Free Standing Range, 240VAC, Model # 911.93411000, broiler element used as infrared heater.
Procedure:
Water in bowl, thermometer probe in water. Initial reading 75°F (no decimal), room temperature. Bowl placed inside oven chamber. Bowl resting at center of factory-original steel grid oven rack with water surface at approximately 8″ from broiler element.
Broiler element was turned on, door was left ajar to minimize heating of the bowl and water by heated air in the chamber. Water surface was still.
Results in CSV format:
Time,Temperature
min:sec,°F
0:00,75
0:30,75
1:00,75
1:30,75
2:00,75
2:30,75
3:00,75
3:30,75
4:00,75
4:30,76
5:00,77
5:30,77
6:00,78
6:30,78
7:00,79
7:30,80
8:00,80
8:30,81
9:00,83
9:30,84
10:00,85
Experiment was terminated due to concern over notable acceleration of rate of warming. After shutting off the infrared heater and examining the chamber with the goal of removing the bowl, it was determined the bowl rim had begun thermal-based deformation. Containment of the water had not been lost. After partial cool-down the bowl with water was removed from the chamber. It was observed that the integral base did not have any deformation marks from the individual rods of the steel rack, indicating the steel rack was cooler than the bowl rim.
Except for the rim, there is no noticeable deformation of the bowl. As the rim deformed and solidified into a flexible state apparently unchanged from before, the material is identified as a thermoplastic plastic, not a thermoset plastic.
There was no noticeable production of steam or any other form of water vapor.
Discussion: Output of infrared heater was applied to surface of water. Chamber was not preheated. Temperature of water increased after an apparent warm-up period. It was already known that excessively prolonging the experiment would lead to likely catastrophic containment failure, thus it was planned for it to be terminated upon possible signs of possible container deformation, and it was.
It is clear the water was warmed. But it is also clear the plastic of the bowl absorbed the emissions of the infrared heater, as the plastic nearest to the heater that was not able to effectively use the water as a thermal sink did deform.
As it cannot be determined how much of the heating of the water was due to direct absorption by the water of infrared heater emissions and how much of the heating was from the heating of the bowl due to the emissions, it is evident the bowl used was not made of the proper material for use with this heat source.
Conclusion: Due to deficiencies in experimental apparatus, the proposition has been neither confirmed nor falsified.
Additional: A proper design for this experiment would use a container that will be unaffected by the expected temperatures and that will not directly absorb the emissions of the infrared heater, which would indicate a metal like stainless steel, that will not allow the water to absorb ambient chamber heat, which would not indicate metal.
The recommendation would therefore be for a stainless steel bowl (or similar container) that sits on a base of an insulating and non-heat retaining material such as that used for lightweight fire bricks (examples) or a supporting mat of a material like Kaowool (examples). The insulating material would have to cover the exterior of the bowl up to at least the water level. Ideally the insulation would go to the rim with the water level up to the rim, but a relatively small amount of container above the insulation and the water surface would yield a negligible difference.
Without such a setup to control the confounding possibility of the container heating the water, it is unlikely any meaningful conclusion can be drawn from the attempted heating of water by an infrared heater.
Interestingly enough my data confirm a trend of about 0.15 degree C per decade warming both on maxima and mean temperatures.(note that my tables are laid out in degrees C per annum)
http://blogs.24.com/henryp/2013/02/21/henrys-pool-tables-on-global-warmingcooling/
However, a problem turns up if we look at the warming from 2000?
Stop worrying about the global warming, start worrying about the global cooling.
http://blogs.24.com/henryp/2013/04/29/the-climate-is-changing/
1st it was Hansen’s Ice Age followed by the boiling planet. Can we get him some Prozac, in fact, Obama needs some as well. It’s treason what these people have done to our nation. All the weather channel talks about is climate change this and that. Tornado’s are down, Hurricanes are down and the insurance companies are cleaning up on Gore’s constant lying. Wake up people, nobody can even get close to what the earth is going to do next…….dah!!!!!
Man is nothing more than an ant in a tiny corner of the universe….that’s it, nothing more, nothing less.
Steven Hill says
Man is nothing more than an ant in a tiny corner of the universe….that’s it, nothing more, nothing less.
henry@steven
Where is your faith?
http://blogs.24.com/henryp/2013/03/01/where-is-your-faith/
richardscourtney: Thank you for trying to make that clear. Can I summarize it as, “There’s more noise in the system than we assumed”? If so, aren’t we just back with Lorenz’s discovery that chaotic systems produce output that looks like noise? If that’s the case then it’s the noise that has to be modelled not condensed into “error bars”. (I do know it’s not you I’m arguing with. Thanks for your efforts to explain the climate modellers’ thinking).
It’s as though they mean to say “stopped”, but somehow it comes out as “slowdown”. Probably something to do with knowing on which side their bread is buttered.
Reply to Richard Courtney
richardscourtney says:
September 5, 2013 at 3:20 am
You say that my comment is both irrelevant and disruptive in this thread. I don’t see how it can be both, although it might be one or the other. As it happens, my comment seems to have passed by without disrupting the discussion. So that leaves its irrelevancy. Part of the main article in question makes the following claim.
“Global mean surface temperature over the past 20 years (1993–2012) rose at a rate of 0.14 ± 0.06 °C per decade (95% confidence interval)1.”
I’m no expert in 95% confidence intervals as used by statistitians, but even so I’m 100% confident that the (+/-(0.06))*C margin of error mentioned is ludicrously small. I’m just an old twerp who only became interested in global warming etc upon becoming an old age pensioner, so what do I know (?) except that these margins of error are of capital importance when estimating mean global surface temperatures. If I have bee in my bonnet, it’s that these margins of error are always ridiculously small, and I’ll not apologise for that.
Steve Keohane says:
quote
Gail, isn’t the ‘normal’ state of the ocean surface ‘frothed’, due to wave and wind action?
unquote
While we’re doing experiments:
Do various heating-from-above experiments with water that has been rigorously cleaned and the same water that has been polluted with a mix of light oil and surfactant.
Difficult to simulate wave action though, as the bowl won’t be big enough, but we can observe from nature that the mix suppresses waves. I wonder what happens to heating when the surface frothing is suppressed?
JF
Steven Hill from Ky (the welfare state) says:
> So, when this is all over, who’s going to take Gore to court for all the damages he has caused?
I hope somebody properly skilled tries that, but I am sceptical of the outcome. How can you punish somebody for delivering something that was so universally acclaimed? With ecstatic audiences screaming for more? Can’t charge one for rape if it was consensual, I’m afraid.
The real damages were caused by Gore and nearly half the population of the planet. Can we sue them all?
Worthless. Waffle and weasel words that appears scientific, but is not.
Begin with the divergence begin in the early 1990’s; or when the models began running. The models were wrong from the get go and should have been tested, qualified and certified before ever running simulations for use.
With uncertified unqualified models that have no accuracy to observations; these folks than have the nerve to claim that the models “…generally simulate natural variability…”. The operative word is “generally”, meaning in their opinion, not verified testing.
“…By averaging simulated temperatures only at locations where corresponding observations exist…” This is a statistically valid method? Do the errors from the other locations carry on through? This phrase looks like ‘cherry pick’ in capitals and they still can’t get what they want.
This averaging is after running the models 117 times. Why 117 runs? Why not 125 runs or 300 runs or 10 runs… Such an odd number that 117 runs, smells like…
They have what can only be termed massive observational evidence against the models and in their final sentences they slip in a word ‘suggests’ and then a phrase ‘temporary hiatus in global warming’ with their use of the word ‘hiatus’ within apostrophes for emphasis.
Only absolute faith in the unproven theory of anthro global warming can underlay that temporary phrase, as it certainly isn’t in the evidence. Instead, the authors should have declared the models useless until corrected and independently certified. They should also be seriously considering whether anthro contributions to AGW can truly be accurately identified outside of natural variability. I agree with RichardsCourtney about how this phrase is correctly described, (lie), but differ slightly on what the authors should have said.
I’m confused by the numbers here. If the 15 year trend in the models is .21C per decade, while the 20 year trend is .30C per decade, then that would mean the models calculated .315C warming for 15 years and .60C for 20 years, and thus a cooling of .285C from 1993 to 1998.
Listen to this crap:
It is worth noting that the observed trend over this period — not significantly
different from zero — suggests a temporary ‘hiatus’ in global warming.
The observed trend does not suggest that the cessation of warming is temporary. That’s a lie. And the use of the ‘hiatus’ makes the lie redundant.
The evidence, therefore, indicates that the current generation of climate models
(when run as a group, with the CMIP5 prescribed forcings) do not reproduce
the observed global warming over the past 20 years, or the slowdown in global
warming over the past fifteen years.
“Do not reproduce the observed global warming”? WTF kind of stilted sentence construction is that? And ‘slowdown in global warming’? It didn’t slow down. It stopped. These sort of linguistic tricks to hide the truth and imply lies are propaganda techniques, not honest scientific communication.
Stated plainly, the evidence indicates that the current climate models grossly exaggerated the observed warming over the last 20 years, and predicted even greater warming still, when in fact there was none at all for the past 15 years. This, therefore, demonstrates that the models’ predictions were bad, and have become even worse. The observed trend over this period suggests that anything that these models predict for the future is absolute bullshit.
Geoff Sherrington:
In your post at September 5, 2013 at 5:16 am
http://wattsupwiththat.com/2013/09/05/statistical-proof-of-the-pause-overestimated-global-warming-over-the-past-20-years/#comment-1408491
you say
It seems you don’t understand this thing called ‘science’.
The first stage of a scientific investigation is to admit you don’t understand an observed effect.
After that you can start the process of determining what you don’t understand.
And that process is prevented by pretending that
(a) the effect doesn’t exist because it is not understood
or
(b) that you understand the effect when you don’t.
I wonder where you obtained your mistaken and anti-science idea that a mechanism should be ignored unless its mechanism is understood. Perhaps from climastrologists?
In reality it is a STRENGTH (n.b. not “weak”) to acknowledge what is observed but not understood because that can lead to understanding “which is consistent with measurements”. Indeed, if an understanding is not “consistent with measurements” then it is not a true understanding.
And that is what this thread is all about. The modellers built their climate models to represent their understandings of climate mechanisms. If their understandings were correct then the models would behave as the climate does. The fact that the climate models provide indications which are NOT “consistent with measurements” indicates that the understanding of climate mechanisms of the modellers is wrong (or, at least, the way they have modeled that understanding is in error).
Richard
richardscourtney says: @ur momisugly September 5, 2013 at 4:04 am
I fear we may be straying too far from the important subject of this thread….
>>>>>>>>>>>>>>>>>
I think it is all related since the inability of the models to preform as advertised is because they completely miss the boat on how the climate actually works.
richardscourtney says:
September 5, 2013 at 1:55 am
Until now the modellers have assumed effects of internal variability sum to insignificance over periods of ~15 years.
====================
that really is the crux of the problem. the assumption that natural variability is simply noise around a mean. and thus will average out to zero over short periods of time. chaos tells us something entirely different.
chaos tells us that averages are an illusion of your sample period. as you increase the sample period longer term attractors will come to dominate, changing the long term average without any change in the forcings.
this is completely overlooked in the climate models, which assume that any long term change can only be a result of a change in the forcings.
We sometimes use a 150 gallon metal cattle trough heated with a propane weedburner as a makeshift jacuzzi at our cabin in the woods. The first time we tried to heat it in the winter, we blasted the weedburner at the side of the trough for hours and to our amazement it barely heated the water at all. We wisened up, placed the trough over a shallow trench in the sand, blasted it lengthwise across the bottom and it nicely heated up to temperature in 45 minutes. I suspect if we attempted to blast the weedburner at the waters surface we’d still be waiting for the water to heat up.
I concluded that a large volume of water is best heated from the bottom.
I am pleasantly astounded at how quickly discussion of the ‘pause’ has passed from heresy to mainstream. Now all someone has to do is publish the ultimate taboo: natural variability can push temperatures up as well as down.
I am also hugely enjoying KD Knoebel’s rather off-topic but superbly dry experimental reports. There is some ground-breaking determination of the properties of plastics going on right before our eyes: “… the material is identified as a thermoplastic plastic, not a thermoset plastic.” Insightful. I’m sure the Slayers are learning a lot, if they can keep up.
Steve Keohane says: @ur momisugly September 5, 2013 at 5:15 am
Gail, isn’t the ‘normal’ state of the ocean surface ‘frothed’, due to wave and wind action?
>>>>>>>>>>>>>>>>
It varies. The Horse Latitudes (between 30 and 35 degrees, north and south) were called that because of all the dead horses tossed overboard when the sailing ships got stuck in a no wind situation.
That is why both experiments are of interest.
Nick Boyce:
Your post at September 5, 2013 at 6:35 am begins
Say what!?
The subject of this thread is far too important for semantic disputes.
This links to my post so anybody can easily read what my post said
http://wattsupwiththat.com/2013/09/05/statistical-proof-of-the-pause-overestimated-global-warming-over-the-past-20-years/#comment-1408432
Richard
Geoff Sherrington says: @ur momisugly September 5, 2013 at 5:16 am
I think it is weak to argue that the Earth is recovering from an LIA unless a mechanism is given, one that is consistent with measurements.
>>>>>>>>>>>>>>>>>>>>
See my comment above on Dansgaard-Oeschger (D-O) events. They are called Bond events during an interglacial.