Bishop Hill Beddington on tipping points
Jun 19, 2012 CSA Sir John Beddington's contribution to a paper on climate change for the Chartered Institute of Insurance is worth a read. Here he is on tipping points:
There is wide acceptance in the scientific community that there are also likely to be ‘tipping points’ in the climate system which, if crossed, could result in long-term or irreversible changes to our climate. The warmer our climate gets, the greater the likelihood of passing a ‘tipping point’; be it accelerated (and/or irreversible) melting of the Greenland or West Antarctic Ice Sheets, which could significantly increase sea levels, or changes to large-scale atmospheric and oceanic circulatory systems, such as the Gulf Stream, which could potentially fundamentally alter regional climates.
I'm aware of Tim Lenton's paper (with co-authors such as Schellnhuber and Rahmstorf) on tipping points - the result of a confab at the British Embassy in Berlin. But what other support is there for the idea of tipping points in the climate? Do these emerge unbidden from climate models? I certainly seem to remember someone reporting that changes to the Gulf Stream were now being downplayed - see this from Wikipedia for example:
Modelling suggests that increase of fresh water flows large enough to shut down the thermohaline circulation would be an order of magnitude greater than currently estimated to be occurring, and such increases are unlikely to become critical within the next hundred years; this is hard to reconcile with the Bryden measurements.
Reader Comments (63)
DJ,
This graph is from ice-cores in Antartica and there are similar graphs from ice-cores in Greenland. It almost certainly shows large shifts related to “tipping points”.
The shifts are between two states, like going through a one-way door. Once you are through, the change is complete, there is no death spiral. You can get back, but you need to find a different door.
Large shifts - as in the Vostok graph - are very rare; but many people think that perhaps 10 or so smaller ones were encountered during the 20th C. Nothing particularly to do with CO2, natural changes that caused small steps in our climate, up or down.
Jun 19, 2012 at 5:44 PM | Bruce Stewart
Why would a maths book Thompson and Stewart, Nonlinear Dynamics and Chaos refer to 'dangerous bifurcations'?
Surely, in maths, a bifurcation is a bifurcation - it doesn't need an adjective.
Jun 19, 2012 at 7:31 PM | Billy Liar
Some bifurcations involve no hysteresis; if you are turning the knob slowly, and you realize that a bifurcation is happening or about to happen, you can dial back the control knob just a little bit and undo the bifurcation. Depending on the application, this may be a less risky situation than if there is hysteresis, where the bifurcation can not be undone without a potentially large dial-back. So a bifurcation without hysteresis may be usefully called "safe" while a bifurcation with hysteresis is potentially more "dangerous."
Sort of like tickling a sleeping dragon: if the dragon wakes up gradually, you can get the heck out; if it wakes up instantly and pounces, you are toast.
Jun 19, 2012 at 6:00 PM | Rhoda
I agree completely.
hypothetical tipping points poorly understood + precautionary principle = recipe for error
I'm curious how one can get away with picking out some wild speculation and declaring "There is wide acceptance in the scientific community... [on said speculation]" and never being held to account on that.
"Tipping points" seem to be the means of choice to frighten the whole world that they MUST! ACT! NOW! GLOBALLY! with scientific expertise. "Tipping points" are obviously beloved by bureaucrats and administrators.
Beddington, UK chief science advisor repeated in a 2008 paper (http://rstb.royalsocietypublishing.org/content/365/1537/61.full) the claim that in 2035 the Himalayan glaciers will be gone.
Jo Schellnhuber, for instance in 2007, he--a "tipping point expert"--was appointed Chief Government Advisor on Climate and Related Issues during Germany's EU Council Presidency and G8 Presidency, repeated that error of Himalayan proportions in 2009 during a nationwide public broadcasting on television in Germany.
Jean-Pascal van Ypersele (IPCC Vice-chair) used the 2035 scare as policy-relevant in November 2009 (cf. http://klimazwiebel.blogspot.de/2010/05/himalaya-claim-significantly-used-by.html).
Achim Steiner, UN Under-Secretary-General and Executive Director, United Nations Environment Programme, stated (Merian, October 2009 (http://www.merian.de/magazin/himalaya-asien-trinkwasser.html)) that the complete Himalayan glaciers would be melted in 2035 (it seems to be obvious that nobody complained about Steiner's claim, ever (at least, you won't find anything on the internet)).
So the fear-mongering continues, just with slightly other targets; business as usual and genuine scientific uncertainties. See for instance "GEO-5 SUMMARY FOR POLICY MAKERS (2012)" (http://www.unep.org/geo/geo5.asp# especially for example http://content.yudu.com/A1vr3p/GEO5SPM/resources/a38.htm), Achim Steiner (back of book):
Agenda 21 anyone?
Doug - thanks for the reply. I can feel some major fundamental disagreements on the approach.
(I do hope you appreciate frankness, and rest assured I am not trying to convince you of anything!)
1. You say you don't know much about positive tipping points. Like with Adam Corner's psychosocial studies only of skeptics, this doesn't sound like the wisest way towards understanding tipping points in general and independently from their "policy value".
2. You say you "would expect a policy maker to take in information from a large number of sources on this". But you're aware the policy maker will never hear about positive tipping points, from anybody at all. This removes value to the advice and information you yourself provide, sort of telling a ship's captain to steer away from the continent port-side whilst the two of you don't notice the island approaching from starboard.
3. You are of the opinion that "there is a strong argument that an abrupt change in climate would likely affect social and ecological systems negatively". Not really. I can see the problem from a Development Studies perspective thanks to some University-level studies of mine in that respect. There is an approach there called "Vulnerability Analysis", where poverty is defined in terms of number and size of one's vulnerabilities. Abrupt change of any sort of course will affect negatively the most vulnerable, simply because almost everything affects negatively the most vulnerable. Imagine somebody starving for a week, even eating food will become a risky activity for them.
This tells us nothing about the negativity of the change. OTOH the effect of the change on the less-vulnerable will depend on what kinds of vulnerability they suffer from. A priori, it is impossible to tell if change and even abrupt change will be overall negative or positive.
For example the invention of the internal combustion engine has been an abrupt, enormous effect on societies everywhere, but who would say it has been negative in general? And like there is no such a thing as a "system" of people that is mostly tuned to a particular environment (travel from Iceland to Senegal to see how flexible human societies are), just as well what happened at Krakatoa means "systems" of the wild can recover in amazing fashions.
Therefore, there cannot be any "strong argument" of the kind you describe. Perhaps there is a diffuse opinion that change=bad and abrupt change=awful, but it is an opinion, not a scientific finding.
4. Your final statement is perfectly logical but conveys a curious, illogical message. You say, "if there was a really large change in some aspect of the climate over, say, the next decade (anthropogenic or not), and climate science hadn't at least warned about it, you would rightfully be angry". Perhaps me, but surely whoever is paying for climate change research.
This is some form of recursive logic.
(a) Somebody finances climate change research with the aim of understanding if there is change in the pipeline and of what kind. This makes sense.
(b) Researchers whose job is to work about climate change with the aim of etc etc, in the face of obvious, enormous difficulties in providing what's been requested think about how best to fulfil their duty. This makes sense.
(c) As the duty is to be able to warn in advance of changes, those researchers arrive at the conclusion that, if anything happens and they didn't warn about it, they will be seen as a failure at their job/profession. This makes sense.
(d) Therefore, those researchers make sure they describe all the possibile negativities, so that nobody will be able to say, "you didn't warn us about this". This makes sense.
However, the end result is that the researchers don't focus any longer on understanding if there is change in the pipeline and of what kind, but mostly on figuring out all the bad things that might happen, and assigning each a probability.
This makes no sense. The information finally provided risks reading like plain-language Nostradamus prophecies with informed risk estimates attached to them. If we did the same exercise about health risks in the home, there would be a law against entering bathrooms and kitchens.
Jun 19, 2012 at 8:38 PM | Bruce Stewart
So in your chaotic systems there is just one 'control knob' you can 'dial back'?
OK, another tack. I've been looking at WUWT on the Younger Dryas event. It seems to me that there are tipping points involved there, and half of them tip to extreme cold. Now even I can see the catastrophic potential of a cold tip. I can't see it in a warm one, but cold..brrrrr. So, for every scary potential warm tip we are inexorably hurtling towrds, there is a truly terrifying cold tip which is receding. Why doesn't Beddington ever talk about that?
I have seen references previously to the '1976 climate shift' without finding a description of a reason for it. Is this an accepted event and is it considered a tipping point?
Lord B - that's a good example. Step functions are of course so much better at describing temperature graphs. They're strong evidence that tipping points exist, yet there's nothing to worry about them so policy makers aren't interested, and tipping point researchers aren't either. So the phenomenon is studied in theory despite real-world data being available.
Gents,
Try here for starters.
Tipping point, climate shift, turning point, regime shift, step change, abrupt climate change, non-linearity, bifurcation are all used to point at the same kind of effect, resulting when the system is pushed across a fold or wrinkle in its state space.
Jun 20, 2012 at 2:02 AM | Billy Liar
The mathematical theory of bifurcations is fully equipped to deal with multiple control knobs. The mathematical approach is that the most common bifurcation patterns will be seen when turning just one control knob at a time. Indeed, "common" essentially means that if you observe a bifurcation turning one knob, you should expect to observe the same type of bifurcation turning any other knob.
After the common bifurcations turning one knob at a time, the theory also considers turning two knobs in coordination, and so on.