From the University of Edinburgh:
Warming slow-down not the end of climate change, study shows
A slow-down in global warming is not a sign that climate change is ending, but a natural blip in an otherwise long-term upwards trend, research shows.
In a detailed study of more than 200 years’ worth of temperature data, results backed previous findings that short-term pauses in climate change are simply the result of natural variation.
The findings support the likelihood that a current hiatus in the world’s year-on-year temperature increases – which have stalled since 1998 – is temporary.
Scientists from the University of Edinburgh analysed real-world historic climate records from 1782 to 2000, comparing them with computerised climate models for the same timescale.
They were able to separate the influence on climate trends of man-made warming – such as from greenhouse gas emissions – and of natural influences in temperature – such as periods of intense sunlight or volcanic activity.
This showed that random variations can cause short term interruptions to climate patterns in the form of a pause or surge in warming, in both the real data and in the models, typically lasting up to a decade. Extreme natural forces, such as strong volcanic eruptions, were shown to disrupt climate trends for decades.
The research highlights the impact of volcanic eruptions on climate, when particles produced can reflect sunlight from Earth, causing long-lasting cooling. The eruption of Mount Tambora in Indonesia in 1815 was among the biggest in recent times, causing a so-called year without summer. Scientists estimate that, if it occurred today, it would cause a 20-year climate hiatus.
Their study, published in Geophysical Research Letters, was supported by the European Commission.
Dr Andrew Schurer, of the University of Edinburgh’s School of GeoSciences, who led the research, said: “Human activity is causing the word to warm, and natural variability can cause this trend to slow down or speed up. Our study backs scientific understanding that climate change can experience periods of hiatus, but the overall trend is towards a warmer planet.”
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This has to qualify as one of the worst press releases we’ve ever seen via Eurekalert. The don’t give the name of the paper, the DOI, or any links to it. We are required to look it up, because, you know, these people are just too busy saving the world to stoop to such serf-like tasks.
Determining the likelihood of pauses and surges in global warming
Andrew P. Schurer, Gabriele C. Hegerl and Stephen P. Obrochta
http://onlinelibrary.wiley.com/doi/10.1002/2015GL064458/full
Abstract
The recent warming “hiatus” is subject to intense interest, with proposed causes including natural forcing and internal variability. Here we derive samples of all natural and internal variability from observations and a recent proxy reconstruction to investigate the likelihood that these two sources of variability could produce a hiatus or rapid warming in surface temperature. The likelihood is found to be consistent with that calculated previously for models and exhibits a similar spatial pattern, with an Interdecadal Pacific Oscillation-like structure, although with more signal in the Atlantic than in model patterns. The number and length of events increases if natural forcing is also considered, particularly in the models. From the reconstruction it can be seen that large eruptions, such as Mount Tambora in 1815, or clusters of eruptions, may result in a hiatus of over 20 years, a finding supported by model results.
Key Points
- The recent hiatus is not unusual in the context of the last 230 years
- Models agree with observations regarding likelihood and pattern of events
- Likelihood increases if natural forcings (e.g., volcanic) are also considered
Figures as they were provided in the preview, no captions given.
I’d tend to believe them more if they could actually show a Tambora style eruption that has occurred in the last 15-20 years, and also explain why the effect of Pinatubo was so short lived if in fact volcanoes are affecting global climate as they say.
I think Willis does a far better job of explaining it here: http://wattsupwiththat.com/2013/05/25/stacked-volcanoes-falsify-models/
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They are finding ways of ameliorating their claims through assumptions based on other assumptions and I agree with the argument that who has time to look argument.
I received formal instruction just about sixty years ago, to the effect that climate was then changing and would always do so. Must have been correct, so why all the fuss?
Tambora led to cooling for a whole of 3 years, perhaps 4 or 5 depending on temp accuracy but by the end it may also have been a natural cold year.
Wonder what has changed that a similar eruption is now supposed to upset the temp for 20 years.
But it will surely scare some. More models needed, surely.
You have to love the gravy train.
Am I the only one thinking that the statement:
“Human activity is causing the word to warm, and natural variability can cause this trend to slow down or speed up”
should actually be:
“Natural variability is causing the word to warm, and human activity can cause this trend to slow down or speed up”?
The first statement smells like scam to me.
Sorry. Mod can you please change it from “word” to “world”. Typo is in the original text, I cut and pasted without proof-reading.
The rush to secure more funding before Paris is running at full pace.
“Extreme natural forces, such as strong volcanic eruptions, were shown to disrupt climate trends for decades.”
Interesting. If I remember, the ring of fire was quiet until a few years into the ” hiatus”. Eruptions may have added to the cooling trend but are not the cause of the cooling trend.
I think that by “hiatus” the authors mean ‘slowdown’ – a more commonly used expression to describe the global surface temperature rise of the past 20 yrs or so.
Of course the ‘busted pause’ still exists, and can be documented in the recently adjusted satellite data, at around 14,000 ft
Is this Bouldon’s, of UEA enquiry fame, den of incompetence?
‘which have stalled since 1998 – is temporary.’ ‘cross my fingers and hope to die’
Or the real question is just how long can we drag on the ‘stalled’ claims for , now we stopped claiming it is still increasing, and will it be long enough for us to fill our boots on grant cash or retire ?
The younger climate ‘scientists’ must go to sleep ever night prying for the end of the ‘stall’ , before long some may even turn heretic and start to ask why their god has let them down when they have shown so much unquestioning faith .
… such as periods of intense sunlight
Excuse #? It’s the Sun that dun it.
What exactly do they mean by that? High Noon?
If they sincerely wanted to separate natural variation from man made variation, all they need to do is subtract the observed data from NOAA’s data.
“The recent hiatus is not unusual in the context of the last 230 years”
The whole point is that during the last decade there has been no warming despite a 10% increase in CO2.
They should only compare with previous decades where there was a similar CO2 increase.
Comparing with the last 230 years is completely misleading, because over most of that period there was no significant CO2 increase.
Well why don’t they do a detailed study of more than 400 years’ worth of data? How about the 500 or so years data from Central England?
Oh but wait. They knew if they went back about 200 years the record would show an over all upward trend, while if they went back further they would find that up until about 200 years ago temperature was DROPPING for a few hundred years. And before that it was rising. And before that it was dropping. Almost like climate is cyclic.
Of course if a “scientist” just wanted to feed the meme that we are all doomed by CO2 cause temperature increases then going back only about 200 years makes sense.
The cherry harvest was good that year.
George Carlin, the comedian was brilliant in skewering the way society uses and abuses words and language. He must be turning over in his grave in the way “Climate Change” is being used. Climate Change instead of meaning the obvious, climate changes, has been tortured to mean humanity is warming the planet thereby destroying civilization.
It’s one thing when society abuses language, quite another when supposed scientists use vague slang terms like “Climate Change” as a scientific term with definitive meaning. For scientists to do this is an atrocious disgrace to the core principles of science.
This alone is enough to prove how shallow climate science has become.
Exactly.
When they say climate change, they are clearly talking about man-made catastrophic global warming, even though that is never stated explicitly.
And as had been pointed out, they are using their conclusion as part of the reasoning they use to reach the conclusion.
By starting out with the assumption that CAGW is occurring and is ongoing, they are able to prove it is occurring and ongoing.
“A slow-down in global warming is not a sign that climate change is ending”
No one has said that climate change is ending .It is happening all the time . What has been said is that climate change is in a pause and these pauses of 30 years plus happen regularly and naturally instead of the straight line warming being projected by the alarmist scientists. The latest pause has been happening for a decade or two . It has been interrupted by an El Nino period and then it is likely to continue for decades more despite what the CO2 levels may be.
I haven’t read the paper, but presumably the key to this is that they used actually climate observations “from 1782 to 2000”. So they explicitly excluded the period of the modern hiatus that they were seeking to explain…?
“….Facts being distorted to create the illusion
That man controls climate, so now there’s confusion
As people no longer know what to believe,
Politicians know it is easy to trick and deceive;
Using fear and ignorance to prove they are right,
And of the real facts we so quickly lose sight….”
http://rhymeafterrhyme.net/man-does-not-know-everything/
A more logical model curve fitting to obsevations would be to fit the “internal model” with and without anthropogenic emissions or CO2 forcing. Adding additional variables just increases the uncertainty (relative error} in the model because the variables are so inter-related.
Your wish is my command…
http://www.phy.duke.edu/~rgb/Toft-CO2-vs-MME.jpg
This is CO_2 only without anything like vulcanism, printed from Octave to be semi-pretty.
[corrected link]
http://www.phy.duke.edu/~rgb/cCO2-to-T-volcano.jpg
This is R output. It shows the best fit to volcanism based on a match between VEI and measured effect on TOA insolation at Mauna Loa, which isn’t likely to be VERY accurate as volcanic emission of aerosols isn’t a simple function of VEI but rather depends on each volcano’s chemistry.
It includes all volcanoes with VEI 4 or greater, and is based on summed ejecta. It necessarily still includes CO_2’s log forcing, because if it didn’t it wouldn’t come close. The base CO_2 curve is the same as the first figure.
Note well that even big eruptions, like VEI 6 Pinatubo in 1991, are completely indistinguishable from ordinary year to year variations. There was a bigger “cooling bobble” in the mid-80s that was NOT associated with any volcano than there was from Pinatubo.
This is pretty solid evidence that vulcanism, no matter how you sum it up, is nearly irrelevant to climate until you reach at least VEI 6, and then it would be fairer to say that it is relevant to weather, not climate, as the effects of even VEI 6 events last at most 2-3 years, not 20 to 30. I have no reliable data for Tambora, but I think the assertion that it caused long term cooling is bullshit. It may well — at 10x more more Pinatubo — have caused cooling for as long as 3 to 5 years — but look even at Krakatoa. A mere blip, and one that isn’t even well synchronized with temperature shifts.
Volcanic aerosols have very little effect on the climate, and then only immediately after major eruptions.
rgb
Note well
Sorry, must have mistyped the URL:
http://www.phy.duke.edu/~rgb/cCO2-to-T-volcano.jpg
This is just silly, although this isn’t the first time I’ve heard the hypothesis expressed. For one thing, there has been no sharp increase in vulcanism at the beginning of or during the pause. For another, we now have direct measurements of the effects of volcanic aerosols from the top of Mauna Loa for the last 60 or so years, and they show quite clearly that even major eruptions have are remarkably short lifetime of effect. Finally, there is the temperature record itself, which shows hardly any change in direct association with volcanic activity and which is quite capable of rising rapidly after a major volcano or falling rapidly when there isn’t one. Even Pinatubo produced hardly a blip in the strong warming that was occurring at the time, and one has to know it was there in order to see its effect as it was no larger or longer than non-volcanic variation on both sides of it.
Then there is the observation that the secular natural variation around a CO_2-only warming hypothesis with modest total sensitivity itself fits a 67 year, 0.1 C sinusoidal model extremely well. This could obviously be pure coincidence, but if it is not it is difficult to see why volcanic activity would be periodic with period 67 years. That doesn’t make it impossible (wait for it, we’ll hear from the planetary tide folks any second now:-) but it does make the causal mechanism difficult to understand.
Finally — and possibly most importantly — there the recent paper covered on WUWT that actually reviewed the effects of aerosols on the climate, something that is apparently one of the least understood aspects of climate science and a free parameter that has been much abused in modelling (where every model sets its own values for the effect of aerosols, all different, and then tunes to the reference period before unleashing the hapless “physics based” model on the future with a my-guess-is-as-good-as-yours parameter set to whatever makes the model come out the way that you want it/expect it to or aren’t surprised by, that is to say, a future with lots of warming). This paper found that aerosols have almost no effect on the climate — which is in precise correspondence with both Mauna Loa measurements of TOA insolation and fluctuation-dissipation theory applied to the temperature record — and demonstrated that climate models with no significant aerosol component, retuned to the reference period, exhibited warming with total climate sensitivity around 1.5 C per doubling, in rather excellent agreement with the entire historical record and not likely to be catastrophic or cause any signficant “climate change”.
This last paper I wish I’d saved/bookmarked as I’ve wanted to repost a link to it more than once, but I’ve got to teach in a short while and have no time to search for it now. It’s well worth a read, or re-read, however, in the context of the current post.
rgb
“(wait for it, we’ll hear from the planetary tide folks any second now:-)”
Dr. Brown in this business one mustn’t take oneself to seriously, so not to disappoint your expectation:
Planets affect Earth’s orbital properties (Milankovic must be the most notable planetarist).
This type of signal
http://www.vukcevic.talktalk.net/NECIUS.gif
is found all the way from Yellowstone to the Hudson Bay but not in the Atlantic EuroAsia or Pacific. I have no clear idea why, but the thermal convection causes hot ‘stuff’ to flow from centre to periphery, cools and falls back. Not beyond reason to see it as an oscillating process. If external gravity forces give it a small ‘nudge’ now and then two will eventually synchronise.
and possible consequence
http://www.crawfordperspectives.com/images/rhodes6_000.jpg
Acknowledging natural variability is good but then that’s what the majority of sceptics say is driving warming. There’s still the failure to nail down climate sensitivity which in turn means they can’t definitively ID any human fingerprint of warming from natural variability. It’s just more pre-Paris arm-waving.
WUWT??
Oh, they mean daytime.
You mean the climate won’t stop changing? Say it isn’t so!!
More desperate disinformation from the calamitous carbonaceous climate cult. They just keep piling it higher and deeper.
Yep, they should be putting into bags and selling it, that way we, the taxpayer, wouldn’t have to foot the bill.
Admitting “natural variation” or “random variation” is deadly to the AGW narrative in my opinion. It is a slippery slope from there to admitting that the influence of these things is possibly GREATER than the influence of human contributions to the trace gas CO2.
Oooh! Cracks are appearing in the armor.