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
Make this sticky? This is huge because of the journal and the authors. Maybe real scientists are seeing so much evidence against AGW that some will tell the truth.
Does anyone know of any PRO-AGW websites that are commenting on the shift toward natural variability and the lack of warming? Or are they all turning a blind eye to it?
While the CMIP5 models may well have warming rates clustered around 0.3 degrees per decade, we shouldn’t forget that these are NOT the models that are being used to influence policy. The ones being use are much more extreme and should have been utterly discredited by now.
An example here in Australia is a CSIRO model that predicts ‘up to’ 5 degrees by 2070, almost one degree per decade. This was the figure quoted by (former) Prime Minister Gillard and used to justify the carbon tax introduced in 2012.
You can bet that President Obama does not read Nature Climate Change.
In short, the journals are comparing the milder models to the real world (and even then they are failing) while protecting from scrutiny the extreme models that are being presented to policy-makers.
There are a few “model trends” which correctly describes “observed trends”. Wouldn´t it be intresting to analyse in what way they differ from the rest?
Try heating the surface of water with a heat gun. At 450degsC the surface should quickly boil, in fact it remains cool. You can not heat water through the surface and thats why they are all having a problem.
And that is compared to the highly manipulated trend created in HadCrud.
I wonder how the models perform against actual reality !
‘Or are they all turning a blind eye to it?’
Deltoid is in a death spiral, the blogmasta (Tim Lambert) departed the scene months ago and slowly the place is being taken over by contrarians. Its also under a severe DoS attack.
The old warmist faithful are simply denying the new reality. They don’t even accept the hiatus, even after I pointed out that 97% of scientists agree that its real.
RMB says:
September 5, 2013 at 12:31 am
“Try heating the surface of water with a heat gun. At 450degsC the surface should quickly boil, in fact it remains cool. You can not heat water through the surface… ”
Honestly that is such a moronic comment I think you were sent here to intentionally bring this website into disrepute !
Friends:
The paper is reported to say
NO! That is an unjustifiable assumption tantamount to a lie.
Peer reviewed should have required that it be corrected to say something like:
It is worth noting that the observed trend over this period — not significantly different from zero — indicates a cessation of global warming. It remains to be seen when and if warming will resume or will be replaced by cooling.
Richard
This ‘histogram’ is based on the actual temperatures
http://www.vukcevic.talktalk.net/CETd.htm
“This difference might be explained by … internal climate variability.” Surely if you’re modelling 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 modelling. They keep saying this and I don’t get it.
It is amazing that all the ‘proofs’ of global warming trends are ‘validated’ by another model or miss-use of statistics and NOT by thermometer. The Vukcevic’s histogram is also based on the annual average and therefore not on ‘actual’ temperatures. The global temperature does not exist, it cannot be measured, not a single property of our atmosphere is global – all the properties are local and climate community should not ignore Essex et al (2007), Kramm-Dlugi (2001) and Butina (2012). Dr Darko Butina
“It is worth noting that the observed trend over this period — not significantly different from zero — suggests a temporary ‘hiatus’ in global warming. ”
What “suggests” that it is temporary?
Ah well we’re getting there slowly. No point in expecting a total and sudden 180. At least it does now seem to be polite to talk about it.
Rich:
Your entire post at September 5, 2013 at 1:18 am says
I will try to explain what they are saying, but please do NOT assume my attempt at explanation means I agree with the explanation because I don’t.
The models assume climate varies because of internal variability. This is “noise” around a stable condition.
The models calculate that climate varies in determined manner in response to “forcings”.
Thus, a change to a forcing causes the climate to adjust so a trend in climate parameter (e.g. global temperature) occurs during the adjustment.
If these assumptions are true then
(a) at some times internal variability will add to a forced trend
and
(b) at other times internal variability will subtract from a forced trend.
Until now the modellers have assumed effects of internal variability sum to insignificance over periods of ~15 years. But the ‘pause’ has lasted longer than that. So, internal variability must be significant to climate trends over periods of more than 15 years if the ‘pause’ is an effect of internal variability negating enhanced forcing form increased greenhouse gases (GHGs).
Unfortunately, this is a ‘double edged sword’.
If internal variability has completely negated GHG forced warming for the recent about two decades, then
internal variability probably doubled the warming assumed to have been GHG forced over the previous two decades.
And that ignores the fact that warming from the LIA has been happening for centuries so natural variability clearly does occur for much longer periods than decades (as is also indicated by ice cores). When that is acknowledged then ALL the recent global warming can be attributed to internal variability so there is no residual warming which can be attributed to GHG forced warming.
I hope this explanation is clear and helpful.
Richard
“It remains to be seen when and if warming will resume or will be replaced by cooling. ”
Right on Richard. That is exactly how it should be phrased. There are multiple indications that it will be cooling. You are also correct that a style editor should have picked that up even if the reviewers did not. Adopting the term ‘hiatus’ was to allow wiggle room for doom-laden forecasters to maintain the story that the heating will come back with more vigour after the ‘pause’.
‘Pause’ implies that the tape will roll when ‘Play’ is pressed again.
By someone.
Or something.
Or not.
Rich (1:18am). You are correct. They should honestly say, my model is wrong. I do not particularly care why it is wrong, as that is for the coders and theoreticians to figure out to try to create a better model. All I care about is the policies which are being implemented, which are hurting millions of families and starving them of energy and money because those models are wrong. I want the politicians to recognise that the models are wrong and to change policy and to throw the warmists out of work and to stop basing dangerously expensive policies on unproven theories backed by fearmongering.
richardscourtney says: @ur momisugly September 5, 2013 at 1:03 am
Richard, if they had modified their statement to say “It remains to be seen when and if warming will resume or will be replaced by cooling.” The paper would never have made it out of
Pal- ReviewErrr Peer-Review. Heck they could have had something similar in the original submission and it got scrubbed.What I find most intriguing is the admission:
So it is not just the last fifteen years it is the last twenty year that the models “do not reproduce”
EPIC FAIL! Now can we all go home and forget this nightmare?
“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. ”
Bullshit.
richardscourtney says:
September 5, 2013 at 1:03 am
Very good point. Another subtle way of presenting The Cause in a favourable light. ie this is only temporary and warming WILL start again soon, hence we cannot let up ‘tackling climate change’.
Translation: keep the funding flowing.
RMB spouted off on September 5, 2013 at 12:31 am:
This is standard “Sky Dragon Slayer” stuff you’re spewing, but, what the heck, tried it for myself.
Proposed: A heat gun 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 Conair 1600W hair dryer, 125VAC, Model 064, used as heat gun.
Procedure:
Water in bowl, thermometer probe in water. Initial reading 74°F (no decimal), room temperature. Bowl resting on white porcelain-coated metal surface (stove top) at 74°F per probe, room temperature.
Heat gun on high, held by hand, outlet aimed at water surface of bowl, approximately 8 inches away at 45° from horizontal, aimed at center of surface. Water surface was notably agitated by the air flow, small quantity of water lost over edge of bowl.
Results in CSV format:
Time,Temperature
min:sec,°F
0:00,74
0:30,74
1:00,75
1:30,76
2:00,76
2:30,77
3:00,77
3:30,78
4:00,78
4:30,78
5:00,79
Discussion: Output of heat gun was applied to surface of water. Temperature of water increased.
Conclusion: A heat gun applied to the surface of water can heat the water. The proposition is falsified.
I tried it, showed to myself you were wrong. How should I have done the experiment so it will yield the result you are certain must happen?
Rich says: @ur momisugly September 5, 2013 at 1:18 am
…. Surely if you’re modelling 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 modelling. They keep saying this and I don’t get it.
>>>>>>>>>>>>>>>>
What they are eluding to but dare not say is “climate variability” = Chaos
FROM the WUWT article:
In other words this study shows that climate is a Chaotic System (DUH!) and therefore ” prediction accuracy will drop off rapidly the further you try to predict into the future.” However when the whole scam (and your gant money) is dependent on computer models ‘predicting’ catastrophic warming (Oh, My we must act NOW!) the last thing you are going to announce is that you have figured out the system is chaotic and therefore all that money for all those computers and models has been wasted.
Why the heck do you think there has been such a big fight over whether or not the IPCC makes ‘Predictions’ or ‘Projections’
John C. Fyfe, Nathan P. Gillett, & Francis W. Zwiers
I tried to find CVs of these authors and found nothing. Also, I’m ignorant of “Nature Climate Change”. Can someone provide information please?
Gail Combs:
re your post addressed to me at September 5, 2013 at 2:07 am
http://wattsupwiththat.com/2013/09/05/statistical-proof-of-the-pause-overestimated-global-warming-over-the-past-20-years/#comment-1408393
I agree both your points except that your second point is even stronger than you express.
Actually the true but unstated finding is that the models do not work for any length of time.
This is implicit because of the LIA issue I mention in my explanation for Rich at September 5, 2013 at 1:55 am
http://wattsupwiththat.com/2013/09/05/statistical-proof-of-the-pause-overestimated-global-warming-over-the-past-20-years/#comment-1408386
And it is why I said to him
Richard
“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”
//////////////////////////
The fact is that during this 20 year period, the rise in temperature has not been linear (even if one applies some light smoothing to account for year to year variability).
All, or almost all, of the rise in temperature these past 20 years has been associated with a one off isolated event, namely the Super El Nino of 1998. Given the uncertainty 0.14 ± 0.06 °C per decade, we cannot be certain that all the rise in temperature is due to this ENSO event, but certainly the vast majority is. When this is taken into account, it is clear that the models are further off target than even this paper suggests.
As regards the hiatus, of course it is temporary only. Sooner or later, it is inevitable that temperatures will begin to change. But as Richard observes, we do not know in which direction that change will take place.
One further point on the pause, if the CO2 warming theory is sound, it becomes ever more difficult for there to be a pause in circumstances of elevated CO2 levels. It would easier for there to be a say 15 year pause (ie., when natural variability counteracts the warming effect of CO2) when CO2 levels are in the range of say 310 to 335ppm. It is more difficult when CO2 levels are in the range of 380 to 400ppm. It will be even more difficult should CO2 levels reach say 420ppm.
The higher the level of CO2 the greater the CO2 forcing. We are told (and, of course, this is a new development not mentioned in previous IPCC reports) that model runs do sometimes project lengthy pauses in the rise of temperature. However, we are not told at what level of CO2 this pause in the model projection occurs. Has any model shown a 17 or so year pause with CO2 levels in the range of 380 to 400ppm (and rising)?
I find it difficult to conceive how any model could project a lengthy pause when built on the assumption that CO2 is the dominant temperature driver and has dominion over natural variability. Of course they could contain a random number generator to input from time to time negative forcings from natural variability and another random number generator to input negative forcings from volcanoes and it is possible that these randomly generated negative forcings coincide to produce a pause, but this would only be short lived since the negative forcings claimed for volcanoes is only short lived. Ditto if they included a random generator to additionally throw La Nina into the mix.
Finally, this type of study is precisely the type of study which the IPCC itself should right from the early days have conducted when auditing the efficacy of its models and their projections. A reprot such as this should be included in AR5 irrespective of this type of paper.
The Ghost Of Big Jim Cooley says:
September 5, 2013 at 12:08 am
Does anyone know of any PRO-AGW websites that are commenting on the shift toward natural variability and the lack of warming? Or are they all turning a blind eye to it?
Note replies to comment #2, #6 & #11 by Dr. Gavin A. Schmidt under Unforced variations: Sept. 2013 at the RealClimate blog (Climate science from climate scientists).
1. Promises a future post on Fyfe & al. 2013 (as soon as it comes out will have to be addressed here)
2. Says that conflating model-observation mismatch to a contradiction “is a huge (and unjustified) leap” (whatever that’s supposed to mean)
3. Repeats old mantra “all theories are ‘wrong’ (as they are imperfect models of reality)” (therefore proving them wrong is not an issue, right?)
4. “Judging which one (or more) are falsified by a mismatch is non-trivial.”
5. Has “no problem agreeing that mismatches should be addressed”
6. Is a strong proponent of incorrect, but “useful” theories.
There you go.