Note: Dr. Judith Curry also has an essay on this important paper. She writes:
My mind has been blown by a new paper just published in Nature.
Just when I least expected it, after a busy day when I took a few minutes to respond to a query from a journalist about a new paper just published in Nature [link to abstract]:
This has important implications for IPCC’s upcoming AR5 report, where they will attempt to give attribution to the warming, which now looks more and more like a natural cycle. See updates below. – Anthony
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Guest essay by Bob Tisdale
The recently published climate model-based paper Recent global-warming hiatus tied to equatorial Pacific surface cooling [Paywalled] by Yu Kosaka and Shang-Ping Xie has gained a lot of attention around the blogosphere. Like Meehl et al (2012) and Meehl et al (2013), Kosaka and Xie blame the warming stoppage on the recent domination of La Niña events. The last two sentences of Kosaka and Xie (2013) read:
Our results show that the current hiatus is part of natural climate variability, tied specifically to a La-Niña-like decadal cooling. Although similar decadal hiatus events may occur in the future, the multi-decadal warming trend is very likely to continue with greenhouse gas increase.
Anyone with a little common sense who’s reading the abstract and the hype around the blogosphere and the Meehl et al papers will logically now be asking: if La Niña events can stop global warming, then how much do El Niño events contribute? 50%? The climate science community is actually hurting itself when they fail to answer the obvious questions.
And what about the Atlantic Multidecadal Oscillation (AMO)? What happens to global surface temperatures when the AMO also peaks and no longer contributes to the warming?
The climate science community skirts the common-sense questions, so no one takes them seriously.
UPDATE
Another two comments:
Kosaka and Xie (2013) appear to believe the correlation between their model and observed temperatures adds to the credibility of their findings. They write in the abstract:
Although the surface temperature prescription is limited to only 8.2% of the global surface, our model reproduces the annual-mean global temperature remarkably well with correlation coefficient r = 0.97 for 1970–2012 (which includes the current hiatus and a period of accelerated global warming).
Kosaka and Xie (2013) used the observed sea surface temperatures of the central and eastern equatorial Pacific as an input to their climate model. By doing so they captured the actual El Niño-Southern Oscillation (ENSO) signal. ENSO is the dominant mode of natural variability on the planet. In layman terms, El Niño and La Niña events are responsible for the year-to-year wiggles. It’s therefore not surprising that when they added the source of the wiggles, the models included the wiggles, which raised the correlation coefficient.
Table 1 from Kosaka and Xie (2013) is also revealing. The “HIST” experiment is for the climate model forced by manmade greenhouse gases and other forcings, and the “POGA-H” adds the tropical Pacific sea surface temperature data to the “HIST” forcings. For the modeled period of 1971-1997, adding the ENSO signal increased the linear trend by 34%. Maybe that’s why modeling groups exclude the multidecadal variability of ENSO by skewing ENSO to zero. That way El Niños and La Niñas don’t contribute to or detract from the warming. Unfortunately, by doing so, the models have limited use as tools to project future climate.
UPDATE2 (Anthony): From Dr. Judith Curry’s essay – she writes at her blog:
The results in terms of global-average surface temperature are shown in Fig 1 below:
In Fig 1 a, you can see how well the POGA H global average surface temperature matches the observations particularly since about 1965 (note central Pacific Ocean temperatures have increasing and significant uncertainty prior to 1980).
What is mind blowing is Figure 1b, which gives the POGA C simulations (natural internal variability only). The main ’fingerprint’ of AGW has been the detection of a separation between climate model runs with natural plus anthropogenic forcing, versus natural variability only. The detection of AGW has emerged sometime in the late 1970′s , early 1980′s.
Compare the temperature increase between 1975-1998 (main warming period in the latter part of the 20th century) for both POGA H and POGA C:
- POGA H: 0.68C (natural plus anthropogenic)
- POGA C: 0.4C (natural internal variability only)
I’m not sure how good my eyeball estimates are, and you can pick other start/end dates. But no matter what, I am coming up with natural internal variability associated accounting for significantly MORE than half of the observed warming.
The paper abstract:
Recent global-warming hiatus tied to equatorial Pacific surface cooling
Yu Kosaka & Shang-Ping Xie Nature (2013) doi:10.1038/nature12534
Despite the continued increase in atmospheric greenhouse gas concentrations, the annual-mean global temperature has not risen in the twenty-first century1, 2, challenging the prevailing view that anthropogenic forcing causes climate warming. Various mechanisms have been proposed for this hiatus in global warming3, 4, 5, 6, but their relative importance has not been quantified, hampering observational estimates of climate sensitivity. Here we show that accounting for recent cooling in the eastern equatorial Pacific reconciles climate simulations and observations. We present a novel method of uncovering mechanisms for global temperature change by prescribing, in addition to radiative forcing, the observed history of sea surface temperature over the central to eastern tropical Pacific in a climate model. Although the surface temperature prescription is limited to only 8.2% of the global surface, our model reproduces the annual-mean global temperature remarkably well with correlation coefficient r = 0.97 for 1970–2012 (which includes the current hiatus and a period of accelerated global warming). Moreover, our simulation captures major seasonal and regional characteristics of the hiatus, including the intensified Walker circulation, the winter cooling in northwestern North America and the prolonged drought in the southern USA. Our results show that the current hiatus is part of natural climate variability, tied specifically to a La-Niña-like decadal cooling. Although similar decadal hiatus events may occur in the future, the multi-decadal warming trend is very likely to continue with greenhouse gas increase.
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Correlation does not mean CAUSATION…
….and then they forget to ask the very basic questions about everything else in concert… These warmists cant see the forest through the trees…
Now all they have to do is figure out what are the factors influencing the AMO and PDO.
They’re going for “Forget the cooling, it’s just nature, warming will resume shortly – and that’s all anthropogenic.” They’re hoping to postpone the collapse of the meme until retirement.
It helps give an “out” to some scientists, but also harms the talking points that all climate change recently is man-made.
What the approach of AR5 gives us the best, I think, is the chance (and need) to refocus on the near alchemy of “positive feedbacks” to achieve scary temps scenarios. The PR peeps already tried narratives getting their suckers to argue for the positive feedbacks. It failed, their best avenue is to ignore that aspect–actually, the most important element of the pseudo-science.
Another enjoyable performance–sure to come–will be the dance how the IPCC “scientists” will try to cautiously save and keep face in their docs, while the pr wordsmiths manipulate the “executive summaries” to say much more, and in scarier ways. IPCC scientist-authors should be held responsible for executive summary accurateness too this time. No more excuses.
Cold AMO + quiet sun = disaster?
Mainstream climate scientists using a computer model have taken account of ENSO. I knew this would happen someday. I knew that even modelers would someday recognize that science should take seriously the natural regularities, such as ENSO, that make up the phenomena of temperature change that they study. This is the beginning of the study of natural variability by modelers and the beginning of serious climate science.
So the world’s largest ocean may have an effect on global temperatures? Wow, that seemed rather obvious.
CO2 causes the planet to warm (since, as everyone knows, CO2 molecules are like little heaters—sarc), then the warmth causes BELOW normal equatorial Pacific SST’s (La Nina), then the La Nina causes the planet to cool off.
Just how many laws of physics and thermodynamics are being broken here?
Oh, I forgot, it’s Climate Science….
Energy is neither created nor destroyed. How does moving it from one location one the planet to another remove the energy?
What this does show is that when you moderate the GCNs with the influence of the big water buffers that the observed looks like the modelled….LOL
So what do the projections look like when you project it out to 2100?
Nothing like a planetary emergency I expect.
Will the pseudo-scientists swallow this rat? Get the popcorn out.
I am still trying to understand as to how all the warmth is supposed to be hiding in the oceans, whereas these guys are actually acknowledging La Nina which contradicts the warmth hiding in the oceans. Is CAGW simply a system which will collapse all on its own because it will not be able to cope with all of the contradictory scenarios to which it must adhere?
philjourdan says:
August 28, 2013 at 5:25 pm
“Now all they have to do is figure out what are the factors influencing the AMO and PDO.”
Right. They will have to discover the natural regularities that underlie the AMO, the PDO, ENSO and many other phenomena. We will have a mature climate science by the year 2100. No serious scientist expected anything different. Alarmists, some of whom are scientists, thought they could provide enough evidence for CAGW to move the public without actually doing the science. Now the real science can begin.
The significance of this, is that GHG theory predicts GHGs warm the ocean surface. Hence increasing GHGs must increase SSTs, except to the extent that warming gets transferred to either the atmosphere or the deeper ocean.
With GHGs increasing, and SSTs and atmospheric temperatures not rising, the only place for the predicted warming is in the deeper ocean. Hence Trenbeth going about the missing heat in the deep oceans.
What this paper does is close off alternative explanations to deeper ocean warming.
The Guardian now sees the oceans. The oceans ate my global warming.
http://www.theguardian.com/environment/2013/aug/28/cooling-pacific-dampened-global-warming
http://www.theguardian.com/environment/climate-consensus-97-per-cent/2013/aug/28/global-warming-oceans-known-unknowns
As they say: The truth will out.
A.D. Everard says:
August 28, 2013 at 5:26 pm
“They’re going for “Forget the cooling, it’s just nature, warming will resume shortly – and that’s all anthropogenic.” They’re hoping to postpone the collapse of the meme until retirement.”
They will have to back off on the amount of warming. On this model, ENSO accounts for over half the warming.
Maybe I should have emphasized “The truth will OUT” more.
Ok, I’m confused. The oceans which are hiding the heat, except when there is a roving hot spot, are causing the cooling which is preventing the warming? Lord help us all.
So by finally including Earth’s major atmospheric/oceanic climate cycles, standard-issue Green Gang devotees are surprised to find that –yes– Luddites’ “anthropogenic CO2” is a virtually homeopathic factor in long-term global temperatures. Who’d a-thunk it?
Next up: Breathing causes cancer in rats. As a precautionary principle, best stop breathing NOW.
OK…so here is the dumbed down version:
The oceans ate the heat, so the scientists will have to choke on dead rats.
Let’s see — the cooling is natural but the warming is caused by humans. Seems like I already have that paper somewhere…
(from) The paper abstract:
“……Although similar decadal hiatus events may occur in the future, the multi-decadal warming trend is very likely to continue with greenhouse gas increase.”
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So, we’ve got “similar”, “may occur”, and “very likely” all used in the same sentence.
I get it… it is an opinion piece.
Which justified the funding received, or the hope for more.
I suppose if you start with a pre-conceived notion and the go looking for it, you will always find something. Not exactly the scientific method – we know that warming is real and should be carrying on unabated so lets look for something to explain why it isn’t.
How long do you have to go before you realise that the modelling that you based your pre-conception on is patently inadequate?
this has been being discussed at arstechnica all day:
http://arstechnica.com/science/2013/08/recent-slowdown-in-atmospheric-warming-thanks-to-la-nina/
of course, their conclusion is that…
“Also in accordance with reality, energy trapped by greenhouse gases continued to increase in the model, with ocean heat content rising apace. The modeled climate system didn’t cease warming; it just didn’t show up strongly in the atmosphere.
It adds up to a pretty coherent picture pointing to a cluster of La Niñas as the cause of the slowdown in atmospheric warming. But why all the La Niñas? The researchers chalk it up to natural variability—a lot of coin flips have simply come up La Niña lately. If that’s the case, the researchers write, “the hiatus [in atmospheric warming] is temporary, and global warming will return when the tropical Pacific swings back to a warm state.”
the comments are also depressing to read
Ahhh, what?
“Despite the continued increase in atmospheric greenhouse gas concentrations, the annual-mean global temperature has not risen in the twenty-first century…”
Someone in the Matrix now dares to admit this?
This is news to me. I keep coming across violent denials of it everywhere.
Either way it seems to me that even if atmospheric forcing is important, this paper supports a view that the rate of temperature rise is not going to be as quick as the models suggests.