A survey of climate scientists reveals uncertainty in their predictions of changes to the global climate, yet finds that they believe there is a real chance of passing a “tipping point” that could result in large socio-economic impacts in the next two centuries. The expert elicitation was conducted between October 2005 and April 2006 with a computer-based interactive questionnaire completed individually by participants. A total of 52 experts participated in the elicitation (see Table S2 in the PDF below for names and affiliations). The questionnaire included 7 events of crossing a tipping point. Elmar Kriegler and colleagues asked the climate experts to estimate the likelihood of impacts to components of the climate system under different warming scenarios.
The five systems discussed in the paper concerned major changes in the North Atlantic Ocean circulation, the Greenland and Western Antarctic ice sheets, the Amazon rainforest, and El Niño. The probabilities given by the experts varied widely, but on average, they assigned significant chances to a tipping point in this or the next century for at least the medium to high warming scenarios.
Using the experts’ more conservative estimates, the authors calculate a 1 in 6 chance that a tipping event will occur if the temperature increase in the next 200 years is between 2 and 4 degrees Celsius. For a higher temperature increase, the probability was just over 1 in 2. According to the authors, the results suggest that the large uncertainties that come with climate predictions do not imply low probability that catastrophic events will occur.
Since the survey was conducted in 2005 and 2006, I wonder if the opinions are equivalent today. They might have gotten more bang for their buck if they’d used a survey company like Gallup. I’m sure the results would be faster.
The paper is titled: Imprecise probability assessment of tipping points in the climate system
Elmar Kriegler, Jim W. Hall, Hermann Held, Richard Dawson, and Hans Joachim Schellnhuber,
Potsdam Institute for Climate Impact Research, PO Box 60 12 03, 14412 Potsdam, Germany; Department of Engineering and Public Policy, Carnegie Mellon
University, Pittsburgh, PA 15213-3890; School of Civil Engineering and Geosciences, Newcastle University, Newcastle-upon-Tyne NE1 7RU, United Kingdom;
Tyndall Centre for Climate Change Research, United Kingdom; and eEnvironmental Change Institute, Oxford University, Oxford OX1 3QY, United Kingdom
Edited by William C. Clark, Harvard University, Cambridge, MA, and approved February 2, 2009 (received for review September 16, 2008)
Here is their diagram of the tipping possibilities in the global climate system:
Here is the PNAS abstract
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O.K.
I have a slightly OT question here that I haven’t seen addressed, or, if I have, then my noggin hasn’t recorded it.
But.
What is the function of the internal temperature of the earth on earths temperature? I see discussion of earth as a black body, grey body, etc, etc, etc, but, nobody seems to want to think about the fact that the earth has a MOLTEN core, and an approximate constant soil temp of 56 degrees F or so. How much does this play into climate models and temperature.
Thanks and hope this is O.K. to ask here.
That picture is hilarious-seriously, Watts Up With That?
I saw a great comic dealing with one potential problem using windmills as an alternative energy source here . I’m a fan of this comic but this is the first time that he’s done anything dealing with the global warming “crisis”. Thought the readers here would enjoy.
And If my Grandmother had wheels…
I find myself wondering whether the dramatic rise over the years of the almighty ‘tipping point’ cliche will culminate in a runaway effect having recently reached its own tipping point of over-usage. I guess saying it is like wishing it.
I was under the impression that for the last 6 million years or so of earth’s history there was a temperature limit of about 22 degrees C regardless of CO2 levels (up to 7000 ppm)?
http://scienceandpublicpolicy.org/images/stories/papers/monckton/climate_sensitivity_reconsidered.pdf
If in earths history we have has CO2 levels of up to 7000 ppm and a temperature of no more than 22 degrees C, how can there be a “tipping point”? This whole tipping point theory seems weak at best and at worst pure fantasy. Where is the scientific proof of a tipping point? Is there any historical parallel?
This paper has got to be a new low point in climate science. Hopefully there is a bottom down there to stop science from sinking too low.
” Pairs of tipping events A, B are connected with a directed
arrow A 3 B if (i) at least 4 experts judged that some effect of triggering A on the probability of triggering B exists and (ii) they outnumbered the experts who saw no effect of A on B.”
Ohh, that’s really significant, isn’t it?
“Using the experts’ more conservative estimates, the authors calculate a 1 in 6 chance that a tipping event will occur if the temperature increase in the next 200 years is between 2 and 4 degrees Celsius.”
What a joke. This is one of the worst examples of faux-science that I have read since the Summary for Policy-Makers of the IPCC report. Exactly how was this 1 in 6 chance “calculated”? Lets say I follow college basketball (I don’t, really) and am asked by a freind what I think the odds are that Kansas repeats in this year’s tournament. I say 60%. How is this procedure mathematical, and how is it scientific?
It isn’t. Expressing an opinion as to the likelihood of a future event is nothing more than a subjective expression of one’s own confidence in that outcome. There is no calculation, there is no science. It carries no weight whatsoever unless accompanied by some historical track record of the predictor of making previous predictions later proven to be accurate.
I would have loved for someone to include in this questionaire a request that the participants identify all previous examples in which they predicted a climate “tipping event” associated with a given range of temperature increase, and whether the predicted “tipping event” was or was not independently found to have subsequently occurred.
Very UNscientific.
It is to laugh. Hahaha.
I thought this was going to be an article on the dangers of cow tipping which would have required infinitely more science than this pnas paper.
So… so… so … I’m rather lost for words. Is this some kind of subtle satire or Al Gore’s game plan to take over the world?
It appears CMOC is the quarter-back; that must be Al Gore. MGIS is the transatlantic Jim Hansen and, of course, the antipodean DAIS must be Aussie Tim Flannery, the flim-flam man, who could never resist getting up onto a dais.
I suspect NINO is the Canadian fruit-fly guy, David Suzuki, as it appears to emanate from that country.
I don’t know who AMAZ is, but it’s probably not important as (s)he doesn’t go anywhere. No, wait, I know! It’s yet another Canadian, Maurice (Mao) Strong, he who hides in China. Clearly, he’s decided to move to Rio … well, at least close by but out of the way of the authorities 🙂
They forgot one major tipping point.
How much of a drop in global temperature must occur before the AGW proponents become general objects of derision?
Steelbound: did you mean this comic: http://xkcd.com/556/
Within 50 years we will have all kinds of new technologies which will remove fears about CO2, and give people who like to worry something completely different to worry about.
Such assessments of probabilities are fraught with difficulty even in the most controlled circumstances. This doesn’t seem very controlled, because of the multiple issues that could occur. When this has been done in other fields (i.e., assessment of earthquake probabilities in areas where nuclear power plants wer built) the study was clearly focused. Due to the many issues that occur here, along with the various assumptions that would have to be made, I’d say that the old axiom rings true…
There are lies.
Damn lies.
And statistics.
Tipping point? Might be nice if someone defined the term.
Maybe we should ask Al’s wifey.
Been there, done that
Back to basics: what is a “tipping point”?
OK, assassinating the Archduke Ferdinand is one.
Invading Poland?
Blowing up Twin towers
Invading Falklands.
Anyone else see a “tipping point” trend here???
……………. she’d be your whunkle.
(sorry)
What are the chances of rain tomorrow?
That’s a Joke; when I landed on the Docks of New York’s Manhattan Island almost exactly 48 years ago to the day; all my worldy goods were in two wooden crates sitting there on the dock (one was actually full of nothing by LP records) We were inside a Customs enclosure (fence), having done Immigration three days earler in Port Everglades Fla.
After being cleared by Customs, a NY dock hand, who spoke no English at all, towed my two boxes, which were already on a dolly, exactly six feet from the inside of the fence, through a gate to the outside of the fence; where a shipping agent took possession of them with my instructions to ship them to Beaverton Oregon.
The NY dockhand, of apparent Eastern European ancestry, was being hassled my some immigration officers, who imagined he was ship’s crew (Dutch Boat) jumping ship and trying to slip into USA, so they were wanting to see HIS papers (but not mine). Eventually his foreman bailed him out of the mixup; and then he held out his hand for a tip for his six feet of cart trundling, which I could have done myself. We were standing right underneath Anthony’s sign which read “NO TIPPING”. If I had jumped upwards, I would have banged my head on it. The same sign was on every overhead beam the whole length of the docks. So I deposited a nice shiny US Quarter in his palm, which was a significant portion of the total $40 US (and all other currencies) that we had on our persons. Where I came from offering someone a tip was considered an insult; as if he wouldn’t do a good job unless you bribed him with money.
The guy pushed the quarter back at me and mumbled “there’s no tip” or something muffled that sounded like that. So I dutifully put the quarter back in my pocket. The guy exploded; “c’mon ! arf a buck !”. it appears he said “That’s no tip”.
So I pointed to the overhead sign and told him in four letter words to take a long jump off a short pier. I still hate tipping people; it’s a scam.
But as to the earth’s climate having tipping points; given that the orbital parameters stay pretty much what they now are. No system that is as stable as the earth’s climate is, could possibly have tipping points, or it would have tipped a long time ago.
So forget climate tipping points; that’s also a scam; just like tipping is.
George
Ryan,
I agree.
Just seems reasonable that there is only so much solar energy to put into the system. If the icecaps melt (which they have historically), and CO2 rises to 1200ppm (which it has historically), the temperatures could probably get no higher than the historical maximum. “They” say that’s around 22C (give or take) — unevenly distributed with the coldest areas warming most.
Yes, in a “catastrophe”, in maybe a hundred years, some coastlines would move substantially inland (particularly in Florida). People would adjust as things progressed over the decades. Some major cities would be rebuilt inland (seem to rebuild them anyhow every hundred years or so — jobs and progress). More farming area would be created. More living area would be created. Globally, no big deal — maybe even a good thing — even if things do “tip”.
Anyhow, the burden of proof lies with those who actually say these things will happen and can only be “bad for us”.
To Profarmer,
The earth’s core temperature is somewhat unknown with estimates between about 5,000 and 10,000 K. Apparently ongoing radioactive decay continues to keep it warm. I don’t know if there are also tidal forces that also keep it warmed due to the friction internally as the sun’s gravity pulls bulges on the earth crust. It is thought that the icy crust of Europa hides a liquid ocean underneath that is maintained by tidal forces energy since Europa is so close to Jupiter (maybe it’s Saturn; I can’t remember everything).
So earth should have a continuous outflow of thermal energy from the core; through the surface, but I have never seen any calculation or figure for what that flux might be. But it is known from mining operations that the temperature increases by so much for every so many meters underground depth; presumably after some surface skin which is warmest on the outside.
So that would seem to set a maqximum depth for penetration of energy from solar heating going into the earth’s surface. I have no idea what that depth is.
In the oceans, sunlight propagates many tens of metres into the deep oceans, and it gets colder as you go down, at least to some thermocline, and then apparently it continues to get colder with depth; but much slower, till it gets down to about +3 deg C.
Salt water has no temperature of maximum density before it freezes, like fresh water has at +4 deg C, so salt water always has a positive temperature coefficient of expansion; so deep water warmed by penetrating solar energy, expands and rises where it picks up even more solar energy and warms even more; so it continues to rise till it gets to the surface. At the surface it is hottest of all, si it radiates to the atmosphere, and it conducts to the atmosphere, and the warmed atmosphere also rises; and it evaporates into the atmosphere, which takes astronomical amounts of latent heat around 545 cal per gram into the atmosphere.
So convection trumps conduction; and I don’t think there is any such thing as a pipeline feeding solar energy into the ocean depths; ther’s no physical mechanism to do that. Not surprisingly those new diving buoys can’t find any such pipeline either.
George
Anthony,
And this type of unadulterated GIGO gets funded……
This survey was done in 2005-2006 and is probably is irrelevant today.
Some of the participants will have hardened in their views, and others will have changed their minds. Either way the scores will have changed.
Science by polling?
Good. We can dispense with such mundane details as facts, reality, and the like. Just conduct a poll and we shall know the truth in all its glory. And then — voila — we have a consensus.
The problem with this paper is obvious. The selection of experts was arbitrary. It should have been based on a poll to determine which experts were most expert on determining tipping points. Let’s conduct a poll to see if this paper needs further review.
Did they come up with a date when this tipping point will occur?
So, I’m kinda confused…
The concept of “tipping point” seems to imply to me that our climate would shift from its current attractor to some new one.
I haven’t been able to find what people think the new attractor would look like. Some have said Venus, but we’re missing quite a bit of CO2 for that one.
If it’s not possible to construct a model of such an attractor, then maybe it’s because it isn’t there.
If there’s no new attractor to tip to, then there won’t be any “tipping point”.