Researchers find models must account for volcanic eruptions to accurately predict climate change.
From:MIT Joint Program on the Science and Policy of Global Change
By the late 1990s, scientists had observed more than two decades of rapid global warming, and expected the warming trend to continue. Instead, despite continuing increases in greenhouse gas emissions, the Earth’s surface temperatures have remained nearly flat for the last 15 years. The International Panel on Climate Change verified this recent warming “hiatus” in its latest report.
Researchers around the globe have been working to understand this puzzle — looking at heat going into the oceans, changes in wind patterns, and other factors to explain why temperatures have stayed nearly stable, while greenhouse gas concentrations have continued to rise. In a study published today in Nature Geoscience, a team of scientists from MIT and elsewhere around the U.S. report that volcanic eruptions have contributed to this recent cooling, and that most climate models have not accurately accounted for the effects of volcanic activity.
“This is the most comprehensive observational evaluation of the role of volcanic activity on climate in the early part of the 21st century,” says co-author Susan Solomon, the Ellen Swallow Richards Professor of Atmospheric Chemistry and Climate Science at MIT. “We assess the contributions of volcanoes on temperatures in the troposphere — the lowest layer of the atmosphere — and find they’ve certainly played some role in keeping the Earth cooler.”
There are many components of the Earth’s climate system that can increase or decrease the temperature of the globe. For example, while greenhouse gases cause warming, some types of small particles, known as aerosols, cause cooling. When volcanoes erupt explosively enough, they enhance these aerosols — a phenomenon referred to as “volcanic forcing.”
“The recent slowdown in observed surface and tropospheric warming is a fascinating detective story,” says Ben Santer, the lead author of the study and a climate scientist at Lawrence Livermore National Laboratory. “There is not a single culprit, as some scientists have claimed. Multiple factors are implicated. The real scientific challenge is to obtain hard quantitative estimates of the contributions of each of these factors to the so-called slowdown.”
The researchers verified the cooling phenomenon by performing two different statistical tests to determine whether recent volcanic eruptions have cooling effects that can be distinguished from the intrinsic variability of the climate. The team found evidence for significant correlations between volcanic aerosol observations and satellite-based estimates of both tropospheric temperature and sunlight reflected by the particles off the top of the atmosphere.
“What’s exciting in this work was that we could detect the influence of the volcanic aerosols in new ways. Using satellite observations confirmed the fact that the volcanic particles reflected a significant amount of the sun’s energy out to space, and of course losing energy means cooling — and the tropospheric temperatures show that too,” explains Solomon, who is also a researcher with MIT’s Joint Program on the Science and Policy of Global Change. “There are still uncertainties in exactly how big the effects are, so there is more work to do.”
Alan Robock, a professor of environmental sciences at Rutgers University and a leading expert on the impacts of volcanic eruptions on climate, says these findings are an important part of the larger climate picture. “This paper reminds us that there are multiple causes of climate change, both natural and anthropogenic, and that we need to consider all of them when interpreting past climate and predicting future climate.”
“Since none of the standard scenarios for evaluating future global warming include volcanic eruptions,” Robock adds, “this paper will help us quantify the impacts of future large and small eruptions when they happen, and thus better interpret the role of humans in causing climate change.”
This research was led by a team at Lawrence Livermore National Laboratory and builds upon work Solomon conducted in 2011, finding that aerosols in an upper layer of the atmosphere — the stratosphere — are persistently variable and must be included in climate models to accurately depict climate changes.
The research was supported by the U.S. Department of Energy.
h/t to Roger Sowell
For reference, here is the associated paper; (h/t Greg)
http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2098.html
actually this… CRS, DrPH says:
February 23, 2014 at 9:58 pm
It is that the incidence of interplanetary dust on the upper atmosphere is variable, and has a significant effect on cloud formation, which in turn changes the temperature of the Earth’s atmosphere.
isnt so far outta the game.
the recent meteor showers we pass through every so many years? capsomething?? and geminid been quite a lot the last few months too. and its a fairly regular timeframe cycle I gather.
read somewher they reckon incoming dust is in the tons, would have some countable effects maybe?
I know I’ve read this before but have forgotten… what’s the smoothing range in years on all of the pre-1950s temperature data (you know, the hockey stick graph)
Found this on the wiki:
“Also shown, Mann, Bradley & Hughes 1998 40 year average used in IPCC TAR 2001 (blue), and Moberg et al. 2005 low frequency signal (black).”
So, possible that the temperature swings go up and down all the time, but the scientists smoothed it all out in the proxy data, then tacked on non-smoothed data to show the spike in temperatures? Now the temperatures may be on the downswing again so that the 40 year average is not that different from prior history.
Ie. have we been allowing them to compare apples and oranges?
@ur momisugly Yom O’Donnell
As an engineer I always understood the term SWAG to be Scientific Wild Assed Guess as opposed to the more simple WAG, Wild Assed Guess.
I was unaware that we’ve had any major volcano eruptions this millennium (not since Mt Pinatubo) and that was before the ‘hiatus’. Still amazes me that they honestly believe the implication that all of these ‘natural’ causes (volcanoes, the sun, trade winds, etc) have somehow managed to exactly balance the temperature increases the models show ‘should have occurred’ for a period of 17 years. Maybe someone should do a statistical analysis to determine the probability that THAT would happen. I could see it happening for a year or two, but 17? Seems to push the bounds of believability.
Since the science is settled, I see no reason for Santer to explain the hiatus away at all. After all, it clearly shows up on climate models. Oh wait …
For once I would like climate scientists to admit that the science is NOT settled, and to acknowledge that the models have clearly NOT performed well in the short term and should be taken with a grain of salt in the long term. Honesty would go a long way, but alas there is a little thing called largesse granted by govts.
They are doing little more than admitting, the models, if otherwise usable don’t account for all the variables.
How many more missing variables are there? How many of these are random, unpredictable and uncontrollable, rendering even a (magic and unlikely) model capable of a 100% fit to historic data, totally incapable of prediction.
Anyone who has ever been betroth to a mad spouse knows full well the futility of prediction.
As useful as a fit to flawed data.
In my considered opinion which I humbly submit is as good as any man’s, the hiatus is undoubtedly due to the current vogue for white and silver coloured motor vehicles which reflect more solar energy than those more absorbent blue, red or black ones. I am sure the team could find a correlation between the increase in the number of reflective vehicles and the pause if they were to look and that despite the recent emergence of a counterbalancing burning of carbon fuel to drive around all day with your lights on.
I myself have successfully modelled this phenomenon with a tanning lamp and my collection of Dinky toys. Enlisting a local home-brewer to raise the CO2 content of the experimental space showed no measurable effect other than to compromise my ability to maintain proper records after prolonged exposure to the evil carbon source.
The CO2 effect is certainly worthy of further study I think.
My next project however is to build a one to one scale model of the earth and atmosphere together with the rearer parts of the known cosmos and observe it for the next thousand years. Such a strategy will definitely expose the short comings of those piddling but well funded computer programmes.
All donations of spare Lego and Meccano gratefully received.
http://notrickszone.com/2013/12/22/disappearing-excuses-aerosols-likely-not-behind-the-warming-pause/
It is easy to prove that aerosols aren’t doing it.
In a study published today in Nature Geoscience, a team of scientists from MIT and elsewhere around the U.S. report that volcanic eruptions have contributed to this recent cooling, and that most climate models have not accurately accounted for the effects of volcanic activity.
“This is the most comprehensive observational evaluation of the role of volcanic activity on climate in the early part of the 21st century,” says co-author Susan Solomon, the Ellen Swallow Richards Professor of Atmospheric Chemistry and Climate Science at MIT. “We assess the contributions of volcanoes on temperatures in the troposphere — the lowest layer of the atmosphere — and find they’ve certainly played some role in keeping the Earth cooler.”
1) Volcanic eruptions only affect global temperatures for a very limited time period, unless they continue for years.
2) Aerosols only affect global temperatures while in the stratosphere.
3) Aerosols last only a few days in the troposphere and have a regional affect where they are washed out with precipitation.
4) There is no observed scientific evidence that aerosols have played any role in keeping the Earth cooler longer, than a minimum number of years far shorter than the hiatus.
5) Calculating the change in stratosphere aerosols on global temperatures are far too small to represent the change or stability of global temperatures during the satellite era.
6) Sulfates were put into models to try and show how they cooled global temperatures during the 1940s and 1970s, but the change since then in aerosols and global temperature shows they were greatly overestimated and not the cause.
The graphs below show why this article is not supported with scientific evidence.
Conclusion
The change in aerosols during the 20th and 21st centuries are far too small and short to represent the changes and stationary periods in global temperatures.
“if the glove don’t fit, you must acquit” pretty much sums up every theory the Santer’s, Trenbarth’s, etc. come up with to explain the “hiatus.”
Allan M.R. MacRae says:
February 24, 2014 at 3:10 am
Ed, writing a poem about the hiatus is difficult, as there are few if any words that rhyme with hiatus.
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If Ed can figure out where to insert platypus into the poem, then he may be on to something.
Scientists discover new excuse for funding.
Why not blame the cirro-stratus for the hiatus.
There’s only a mystery about the current cooling if you actully bought into the discredited climate models produced by the slow-witted catastrophic global warming crowd.
Could there possibly be a more convincing admission that the science ain’t settled?
“This paper reminds us that there are multiple causes of climate change, both natural and anthropogenic, and that we need to consider all of them when interpreting past climate and predicting future climate.”
In other words the Alarmists desperately run around in circles trying to find explanations as to why their climate projections are wrong. Funny, even during the peak of the Alarmists’ warning period (circa 2004-2008), anyone who could read a chart could clearly see that their projections were not only wrong, but extremely so. And as early as 2009 the Team (Gavin Schmidt, Trenbeth, and Mann et als) privately worried about the “missing heat”. First it was the deep oceans, and then some admitted that ENSO played a part. Now it is volcanoes. As they all wait and pray for the next Super El Nino they work feverishly to get their studies published.
AGW theory is supposed to be settled, yet here is yet another attempt to justify the humiliating pause they neither predicted nor can explain. Is it 9 different ‘explanations’ now, or just the 8?
The entire AGW thing – it’s a volcano-sized shambles, isn’t it.
@Robert of Ottawa:
“Why not blame the cirro-stratus for the hiatus.”
Because they would have to admit that the negative feedback of clouds (especially in the Tropics) is strong enough to negate the effects of that magical Greenhouse Gas – CO2. If they admit that, then their entire house of cards collapse.
And yet when convenient, CO2 from volcanism is cited as the cause of global warming. Remarkably, this is true even when actual geological evidence shows tropical ice at the time of the supposed GHG-induced warming, as during the Late Cambrian, when CO2 levels were several thousand ppmv. This excuse has also been trotted out to explain the end Permian & end Triassic mass extinction events. So volcanoes are used to account for both cooling & warming, whichever better supports CACA.
“Alan Robock, a professor of environmental sciences at Rutgers University and a leading expert on the impacts of volcanic eruptions on climate, says these findings are an important part of the larger climate picture. “This paper reminds us that there are multiple causes of climate change, both natural and anthropogenic, and that we need to consider all of them when interpreting past climate and predicting future climate.”
” all of them “? Good luck! Many of them are totally unpredictable with present technology or possibly never will be predictable. And OBTW, since 70% of the Earth is covered with water, what are we doing to estimate the heat put into the oceans by under sea volcanic activity which may have had an impact upon prior years heating of the environment? The overall system is what is called chaotic.
Anyone know how good this stuff is? Martin Casdagli: “Nonlinear Prediction of Chaotic Time Series”
What a mark of desperation. Rather than just admit the obvious, that their original hypothesis was wrong, they are going thru all sorts of contortions to prove they were right but that unforeseen intervening variables had changed the circumstances.
Look no further. I have the answer for why there is a hiatus. It is the hiatus of the Atlanta Falcons not having been to a Super Bowl since after the 1998 season. And there is a very high correlation coefficient as well, of 1.00.
The AMO index went negative in January 2014 at -0.039C.
Part of the reason for this is there a seasonal trend remaining in the numbers that they are using now (I don’t know why they let this happen and refuse to fix it but the index will naturally peak in the August and hit a low point in February now).
The Index, however, is certainly down from the peak in 1998 of +0.531C. You don’t need phony (and these are phony) aerosol or volcano forcings if you use the AMO Index cyclicality.
http://www.esrl.noaa.gov/psd/data/correlation/amon.us.long.data
Aside from the square pegs and round holes, did they just admit that albedo is completely unaccounted for and that they believe even small changes in albedo completely outweigh even smaller changes in a trace gas? If so, there is another Monty Python clip about Ann Elk for that.
I do not understand what is supposed to be new about this paper, except that the authors are claiming that there have been sufficient volcanic eruptions in the last fifteen years or so to lower global temperatures. If they really believed this then they should have shown how the number and/or strength of these eruptions had increased as compared with, say, the number and/or strength of volcanic eruptions in the previous fifteen years.
The fact that volcanic eruptions can lower global temperatures had been known for at least en years before Arrhenius came up with his hypothesis that CO2 could cause global warming. I cannot find my old schoolbook but here is an extract from one of the numerous articles on Krakatoa.
“The eruption also produced erratic weather and spectacular sunsets throughout the world for many months afterwards, as a result of sunlight reflected from suspended dust particles ejected by the volcano high into Earth’s atmosphere.
This worldwide volcanic dust veil acted as a solar radiation filter, reducing the amount of sunlight reaching the surface of the earth.
In the year following the eruption, global temperatures were lowered by as much as 1.2 degrees Celsius on average. Weather patterns continued to be chaotic for years, and temperatures did not return to normal until 1888.”
source: http://www.sciencedaily.com/articles/k/krakatoa.htm
Sorry, that this is not as amusing as the post by son of mulder who has basically made the same point,.
Meanwhile, back in the Climate Science lab…FUDGE! MORE FUDGE! Is Luci back on the line again? Send her to break! MORE FUDGE!
WAIT! What?!! I thought all the heat was going into deep oceans, now they tell me it never got to the ocean surface at all? Can you believe these jokers?
Oh this pause in our warming won’t do
Lamented the climate scientist who
Grasped wildly at straws shouting
It’s for the Cause!
For warming we blame CO2.