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Beddington on tipping points

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.

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    - Bishop Hill blog - Beddington on tipping points

Reader Comments (63)

From the Ecclesiastical Uncle, an old retired bureaucrat in a field only remotely related to climate with minimal qualifications and only half a mind.

Beddington v. Lovelock.

Jun 19, 2012 at 7:27 AM | Unregistered CommenterEcclesiastical Uncle

Tipping points are the end of a change of faulty reasoning.
If A then could be B. If B were to happen, the many people think C could occur. Under certain assumptions then D - which is going to be really awful.
It all relies on an unstable view of the world, extrapolating well beyond current data, and ignoring negative feedbacks that dampen the amplitude or the timing. Lenton's paper brings together a number of theorists, many with their own alarmist areas. Included are the collapse of the Amazon rainforest, the rapid increase in the Sahel, and the collapse of ice sheets in Greenland and West Antarctica. Since the paper was written, better evidence has been far less extreme, or even gone the other way.
The underlying assumptions are revealed when these scientists look at human costs. The events will happen so quickly for sea level rises for instance, that there will be no time to build dykes, or even move out the way.

Jun 19, 2012 at 7:27 AM | Unregistered CommenterManicBeancounter

Beddington must be getting very desperate to come out with this argument. Even the outgoing director of Greenpeace Gerd Leipold accepted in Stephen Sakur's BBC Hard Talk interview that his organisation issued misleading press releases about the imminent demise of the Greenland Ice Sheet. It is typically minus 40C in winter at the Summit Camp, and despite a warm spell in the last 2 days, it is still -9C there just now. Maybe given the failure of the global temperatures to rise in the last 15 years, Beddington has decided to just go with the emotional argument like Greenpeace did. He was never much of a scientist anyway.

update - That's odd, there's blue skies there just now, the Sun's on the way up, and despite all the extra CO2 and heat in the atmosphere the temperature has has dropped to -10C. Greenland Summit Camp webcam.

Jun 19, 2012 at 7:43 AM | Registered Commenterlapogus

When trying to sell fear, the "tipping point" is a valuable sales tool.

Jun 19, 2012 at 7:51 AM | Unregistered CommenterJack Savage

I remembered reading this so putting it up here

Jun 19, 2012 at 7:53 AM | Unregistered Commenterclivere

There was an excellent post on WUWT regarding the split the scientific community about the Younger Dryas event, this quote seems pertinent.

"Dr. Wunsch was even more emphatic about the role of the North Atlantic in climate changes when he stated that “you can’t turn the Gulf Stream off as long as wind blows in the North Atlantic” and then goes on to say that “the conveyor is kind of fairy tale for grownups”(54). Dr. Richard Alley seems to echo these sentiments when he questioned how the small high latitude North Atlantic “energy starved polar tail” could possibly “wag the large energy rich tropical dog”(55)."

Jun 19, 2012 at 8:34 AM | Unregistered CommenterFrosty

One wonders whether he has any scientific ability at all. I think he has nailed his colours to the mast too many times to allow any credence to anything he says.

As Steve M once wrote

"It is disquieting, to say the least, that UK Chief Scientist John Beddington should describe such negligence as a “blinder well played”.

Jun 19, 2012 at 8:46 AM | Unregistered CommenterConfusedPhoton

In the past there have been some rapid changes in global temperature: the Dansgaard–Oeschger events when temperatures rose by 5 °C over a few decades or the increases and falls of a similar magnitude associated with the Younger Dryas. However nobody knows why they occurred, they assuredly were not anthropogenic, nor what their impacts were.

Extrapolating from events like these to anthropogenic ‘tipping points’ is a leap too far. But no doubt we will hear more of them; they are an easily understood concept and so are useful for scare mongering.

Jun 19, 2012 at 8:48 AM | Unregistered CommenterRon

Bish asked, "But what other support is there for the idea of tipping points in the climate? Do these emerge unbidden from climate models?"

Here are three good places to look for such support:-

Zaliapin and Ghil
Tsonis et al

A "tipping point" is nothing more than a fold in the state space resulting from the non-linear nature of the climate system. They appear in the basic theory, GCMs are poor at reproducing them (as far as I know). The problem is that they are yet another aspect of the basic science that can be taken in two directions, dependent on where you want to get to.

If you want to be an alarmist then you can call it a "tipping point", and talk about catastrophic irreversible changes. If you want to be a a skeptic, then you might call it a "turning point" or a "regime shift", and suggest that they are the basic mechanism behind natural variability. The truth no doubt involves both of these notions. They are IMO easily the best way to visualize the climate system.

Jun 19, 2012 at 9:08 AM | Registered CommenterPhilip Richens

Probably also worth pointing out that contrary to Beddington's assertion, the potentially dangerous turning points are most likely to be found as temperatures decrease.

Jun 19, 2012 at 9:14 AM | Registered CommenterPhilip Richens

Doug McNeall, myself and others wrote a review paper which is relevant here.

It's probably paywalled unfortunately (can't tell from here) but I can send a copy to anyone who emails / tweets me their address.



Jun 19, 2012 at 9:17 AM | Registered CommenterRichard Betts

Hi Richard,

I'd like a copy of your paper please.


Jun 19, 2012 at 9:26 AM | Registered CommenterPhilip Richens

Manicbeancounter: You mention negative feedbacks being ignored.

This is one of the key philosophical divides between alarmists and sceptics. We should be challenging head-on the fallacy that the Earth's climate history is subject unstable equilibrium.

The other one is sensitivity. Demonstrate that the greenhouse effect is trivial and insignificant, dwarfed by other drivers and the apocalypse myth collapses.

This global warming scare is the latest in a historical sequence of scare stories back into the mists of time. What's new is that this time pseudoscience is stealing the credibility of real science; pseudoscientists are the new end-is-nigh doomsayers.

Jun 19, 2012 at 9:32 AM | Unregistered CommenterBrent Hargreaves

These events, cold to temperate, are nothing to do with CO2-GW**. Instead it's probably a temporary reduction of cloud albedo associated with the growth of phytoplankton blooms when ice melt provides Fe nutrient from occluded dust.

It's the mechanism that eventually leads to the end of ice ages, also the 70 year Arctic melt freeze cycle with the 2000s being equivalent to the 1930s, Arctic ice melting but now freezing like the 1940s. As in the 1940ws, winters are now getting colder. In ice ages the temperature pulse has a much higher amplitude because the cloud albedo starts off much higher.

Jun 19, 2012 at 9:49 AM | Unregistered Commenterspartacusisfree

1. Tipping points exist in nature
2. They don't mean systems disintegrate, just that in the most simplified form they go from one stable state to another
3, If the new state is better or worse than the old state, it's a value judgement likely depending on the size of your gene pool
4. However, transitions (critical or otherwise) do not necessarily include just one beginning state and one final state
5. What a “state” actually is, gets less clear the more an example is studied
6. In fact, "The more closely one looks" at a system, "the less the behavior matches theory, because the theory is too simple. There are more than two possible states; indeed, there are infinite gradations"
7. “Critical transitions are rare“

Just like for anything regarding climate, the path of understanding is fixed. We start from ignorance, move on to illusory knowledge and end up realizing how ignorant we still are and forever be.

For more details and the source of the quotes: "Tipping Points Revisited – The Impossibility Of Action Between Rare Examples And Complex Behavior ".

Jun 19, 2012 at 10:13 AM | Registered Commenteromnologos

What I've seen of prehistoric temperature records suggest that there is a plateau of about 22deg (about 10deg warmer than now) that has never been exceeded. The exact opposite of a tipping point, in fact...

Jun 19, 2012 at 10:15 AM | Unregistered CommenterJames P

Aren't climate tipping points the places where climate change-science garbage trucks go to spunk their load?

Jun 19, 2012 at 10:24 AM | Unregistered CommenterReg. Blank

Tipping points were invented because they needed to be.

The climate was warmer than this in both the 1930s and the MWP, and the GAT didn't run away with itself then.

So the argument has to be that this time it's different.This time we have more CO2 and so this is a different, more dangerous sort of "warm".

It's a bit like dark matter, or the God of the Gaps. You have to postulate it and it has to fit the exact shape of the missing feature of your belief model. You can then argue that your model works.

Jun 19, 2012 at 10:27 AM | Unregistered CommenterJustice4Rinka

Beddington is a true believer. In the Spring he was at a civil service indoctrination event talking about extinctions. There can be major events.Hhowever, the Big Mistake has been to assume that CO2-GW is the cause when in reality CO2 climate sensitivity has been exaggerated by at least an order of magnitude by making incorrect assumptions, e.g 33 K present GHG warming when you must take off ~24 K lapse rate.

Jun 19, 2012 at 10:28 AM | Unregistered Commenterspartacusisfree

Hi all,

Richard Betts has already pointed to our paper, but feel free to email me at gmail, with climatestats as the username, if you'd like a copy.

The paper has probably been superseded as a literature review by now, but I still think we say some interesting things about how to think about really big nonlinearities in the climate system.

A few notes:

Various "tipping points" are seen as greater or lesser threats to the Earth system through time. I'm sure some of this reflects social processes, but in many there is *genuine scientific uncertainty* as to whether they constitute a threat.

Individuals, governments and groups have different risk appetites, but personally, I feel that researching high impact (but low probability) events is worthwhile. As a researcher, I feel that it is important not to be shrill about those threats, as many will go away with further research.

However, I do find it very instructive to look at the stated probabilities for some of these events. Some are very high (order 0.1) for catastrophic threats. Institutions have very different risk appetites for different things - anything nuclear, for example, probably because of things like the availability heuristic.

It is interesting to see how the attitudes towards these tipping points change over time. Some are very persistent - uncertainty about the threat of shutdown of the overturning of the MOC has been large since Stommel worked on it in the sixties, for example. Others go away and come back again as new data come in - this happened with the threat of collapse of the West Antarctic Ice Sheet. A lot of the time, we realise that the system is more complex than we thought, but that we can't rule out a major nonlinearity.

It is believed in some circles that GCMs are 'too stable' when it comes to some of these subsystems - they don't show enough nonlinear behaviour. Again, genuine scientific uncertainty.

Happy to chat further, if anyone has questions.


Jun 19, 2012 at 10:32 AM | Unregistered CommenterDoug McNeall

Has anyone said when all these "10-year windows" actually start? I think we should be told!

Jun 19, 2012 at 10:34 AM | Unregistered Commentersteveta

Jun 19, 2012 at 10:34 AM | steveta

Didn't they start when the statement was made so most of them are up or soon will be up, and yet the world survives. Who would have guessed.

Jun 19, 2012 at 10:42 AM | Unregistered Commenterrichard verney



see my comment @ Jun 19, 2012 at 8:29 AM

Jun 19, 2012 at 10:46 AM | Registered Commentermangochutney

Funny thing about points is they can be moved to fit the PR.

Boy I'm getting cynical in my CAGW old age, I even use the incorrect terms for Global Warming.

Jun 19, 2012 at 11:21 AM | Unregistered CommenterShevva

Prof. Beddington is chair of Applied Population Biology at Imperial College. Not anything to do with climate methinks. So out of his area of expertise.
It is models AGAIN putting the alarm bells to ring not real science. All the models show increasing temperature with more heat kept in the system, something to do with the GHG theory I think, but satellite observation shows the opposite- increasing temperatures, increasing radiation/heat loss. I believe the observations.

Jun 19, 2012 at 11:57 AM | Unregistered CommenterJohn Marshall

Alleged "tipping points" are why the Mefieval Warming being warmer than now and the Climate optimum being considersbly warmer is important - and why it is important that the alarmists "£get rid of" them. Obviously no tipping points were reached in either period, therefore no tipping points can exist while global temperature is not above both.

I do strongly suspect that there is a tipping point for cooling sincef the previous ice ages do indeed show a sharp drop at the start of each.

Jun 19, 2012 at 12:07 PM | Unregistered CommenterNeil Craig

Doug - thanks for the offer - awaiting to read the paper (have tweeted Richard my email address) may I start by asking if this line of uncertain research wouldn't have more opportunities for understanding and improvement by being a little less applied and little more fundamental?

By that I mean, your discourse is all built around the threat of this and the threat of that, thereby removing value from state changes that don't threat anything or anybody, still would and could happen and might provide invaluable insight on how and when a state change occurs.

This problem is visible eg when your write about "the threat of shutdown of the overturning of the MOC". As presented, such "threat" appears to be totally subjective, since the probability of the "shutdown" in the real world didn't obviously change with its discovery. It doesn't make much sense to talk about it as expecting to become lower (or higher) just by additional study.

Also there is nothing indicating against the possibility that, rather than a shutdown, there could be a state change resulting in an acceleration or deceleration, with different resulting speeds obviously having their own effects on the regional and global climate.

By only studying the probability of a complete shutdown, we are surely missing out on evaluating the risks associated with a non-shutdown state change, hence our overall understanding of "threats" and "risks" is absurdly skewed towards the very worst: a common feature of all climate mitigation initiatives, if you ask.

It's as if cars were built to protect passengers only against head-on collisions, so airbags would inflate every time one but touched the brake pedal. Very safe, but impossibly impractical.

Jun 19, 2012 at 12:22 PM | Registered Commenteromnologos

Models all the way down.

Proxies all the way back.
Tipping points just around the corner.

Who wouldn't be terrified?

Jun 19, 2012 at 12:27 PM | Unregistered CommenterRhoda

Here are a couple of brilliant comments from a WUWT post on tipping points:

Alex Cull (01:46:57) :
Let me try to summarise – ecologists are warning of something very bad that could happen. Their study tells them that the bad thing might happen at any time, although it has not happened before. They don’t know exactly when this bad thing might happen or what form it will take. They think that it could happen without any warning whatsoever, though. They think that a small “increase” of something or other will cause it, although exactly what they aren’t sure; they think it could be one of a number of different things. But they think they will know it has happened once it has actually happened, although by then it might be impossible to stop it happening or reverse it. Once the bad thing has happened, they think it possible we won’t be able to return to a “desirable state”, although they do not explain what sort of desirable state they would want to return to, other than that it would be a state where the bad thing isn’t happening.

Has that helped?

Richard Briscoe (03:50:18) :

OK, so here’s how it goes.
The effects on ecosystems cannot be seen until you reach a tipping point.
Such a tipping point cannot be predicted, but will arrive without warning.
The argument for a tipping point is therefore simultaneously unverifiable and unfalsifiable.
No evidence can be produced to show a crisis is developing, and its non-arrival never disproves any prediction.

In what possible sense is this argument scientific ?

Jun 19, 2012 at 12:29 PM | Unregistered CommenterBilly Liar

This is the second sentence of the introduction to the paper to which Beddington contributed:

The mega earthquake and tsunami that struck Japan demonstrated in a most tragic way the extent to which even developed nations with advanced infrastructure are vulnerable to extreme weather events.

An earthquake and its tsunami are 'extreme weather' ???!!!

Jun 19, 2012 at 12:39 PM | Unregistered CommenterBilly Liar

Another point Doug - as shown by the last two comments by Billy Liar, all this talk of "threats" ultimately destroys the credibility of a field of research.

Tipping points exist, but the government-sponsored obsession on figuring out how BAD BAD BAD things can be, ends up convincing many people that tipping points don't exist. Next, afraid of being virtually manhandled by berated skeptics, you'll perhaps decide to circle the wagons Phil Jones-style. And there we'll go again...

Jun 19, 2012 at 12:51 PM | Registered Commenteromnologos

I think we discussed this back in March - I have an email from Doug with his paper attached dating from then.

Mathematically, a tipping point is what's called a 'saddle-node bifurcation' or more simply a 'turning point bifurcation', where the graph of the solution against the parameter turns round. Two of these turning points put together make up an S shaped curve, see Fig 1 of Doug & Richard's paper or fig 5 of the Zaliapin and Ghil paper that Philip links to. The inner branch of the S is unstable. If the parameter is changed to beyond one of the turning points, the solution would jump fairly quickly to the other branch of the S.

The big question highlighted by Bish is whether these tipping points occur naturally in models. Well, the answer is that it's very easy to cook up a model that will have them in it. This is the usual problem with mathematical modelling - whatever your pet theory is, you can concoct a model to support it.

A second question is, if there are tipping points, are we near one? Zaliapin and Ghil seem to think we are nearer a cooling tipping point than a warming one, which makes sense historically (ice ages and interglacials etc). One way to tell if you are near a turning point is that if you are, small changes in the forcing lead to large changes in the system, which doesnt seem to be happening now given the recent slowing in warming.

Jun 19, 2012 at 1:05 PM | Registered CommenterPaul Matthews

People who believe in climate tipping points were read the story of "Chicken Little" when they were children, and the phrase "The sky is falling" left an indelible print in their memories.

Jun 19, 2012 at 1:11 PM | Unregistered Commenterdrcrinum

If we agree to “think globally” about climate destabilization and at least one of its consensually validated principal agencies, it becomes evident that riveting attention on more and more seemingly perpetual GROWTH could be a grave mistake because we are denying how economic and population growth in the communities in which we live cannot continue as it has until now. Each village’s resources are being dissipated, each town’s environment degraded and every city’s fitness as place for our children to inhabit is being threatened. To proclaim something like, ‘the meat of any community plan for the future is, of course, growth’ fails to acknowledge that many villages, towns and cities are already ‘built out’, and also ‘filled in’ with people and pollutants. If the quality of life we enjoy now is to be maintained for the children, then limits on economic and population growth will have to be set. By so doing, we choose to “act locally” and sustainably.

More economic and population growth are soon to become no longer sustainable in many too many places on the surface of Earth because biological constraints and physical limitations are immutably imposed upon ever increasing human consumption, production and population activities of people in many communities where most of us reside. Inasmuch as the Earth is finite with frangible environs, there comes a point at which GROWTH is unsustainable. There is much work to done locally. But that effort cannot reasonably begin without sensibly limiting economic and population growth.

Problems worldwide that are derived from conspicuous overconsumption and rapacious plundering of limited resources, rampant overproduction of unnecessary stuff, and rapid human overpopulation of the Earth can be solved by human thought, judgment and action. After all, the things we have done can be undone. Think of it as ‘the great unwinding of human folly’. Like deconstructing the Tower of Babel. Any species that gives itself the moniker, Homo sapiens sapiens, can do that much, can it not?

“We face a wide-open opportunity to break with the old ways of doing the town’s business…..” That is a true statement. But the necessary “break with the old ways” of continuous economic and population growth is not what is occurring. There is a call for a break with the old ways, but the required changes in behavior are not what is being proposed as we plan for the future. What is being proposed and continues to occur is more of the same, old business-as-usual overconsumption, overproduction and overpopulation activities, the very activities that appear to be growing unsustainably. More business-as-usual could soon become patently unsustainable, both locally and globally. A finite planet with the size, composition and environs of the Earth and a community with the boundaries, limited resources and wondrous climate of villages, towns and cities where we live may not be able to sustain much longer the economic and population growth that is occurring on our watch. Perhaps necessary changes away from UNSUSTAINABLE GROWTH and toward sustainable lifestyles and right-sized corporate enterprises are in the offing.

Think globally while there is still time and act locally before it is too late for human action to make any difference in the clear and presently dangerous course of unfolding human-induced ecological events, both in our planetary home and in our villages, towns and cities. If we choose to review the perspective of a ‘marketwatcher’ who can see what is actually before our eyes, perhaps all of us can get a little more reality-oriented to the world we inhabit and a less deceived by an attractive, flawed ideology that is highly touted and widely shared but evidently illusory and patently unsustainable.

This situation is no longer deniable. Opportunities like the one offered at RIO+20 cannot be missed. During my lifetime, many have understood the Global Predicament we are facing now, but only a few ‘voices in the wilderness’ were willing to speak out loudly and clearly about what everyone can see. It is not a pretty sight. The human community has precipitated a planetary emergency that only humankind is capable of undoing. The present ‘Unsustainable Path’ has to be abandoned in favor of a “road less travelled by”. It is late; there is no time left to waste. Perhaps now we will gather our remarkably abundant, distinctly human resources and respond ably to the daunting, human-induced, global challenges before us, the ones that threaten life as we know it and the integrity of Earth as a fit place for human habitation. Many voices, many more voices are needed for making necessary changes

Jun 19, 2012 at 1:13 PM | Unregistered CommenterSteven Earl Salmony

I think one has to ask yourself the question why do large corporate bodies get involved in climate alarmism. Is it because they selflessly care about the world and are willing to sacrifice their profits? We are often told by progressive alarmists this can't be so, so why accept it here?

I suggest not and I think self interest is at work in these climate alarmist/insurance collaborations. When I read the following in this Beddington Chartered Insurance piece I had a feeling of deja vu:

Role of the insurance industry
The insurance industry plays a key role in this scenario by providing economic incentives for the construction and maintenance of resilient property and infrastructure, by raising awareness of climate risks through pricing strategies and knowledge sharing, and by playing a lead role in advising governments about natural hazards and climate change.

It remined me of this from another insurance activist collaboration WWF and Allianz has striking similar language.

The insurance sector could play a potentially valuable role here if it can enshrine the increased probability of an approaching tipping point in terms of greatly increased premiums or even the refusal to insure certain items in certain locations. Such changes would send an economic signal to society at large that may be more effective as an early warning than any number of scientific reports or newspaper headlines.

So the insurance companies get to project themselves as doing some sort of societal service whilst at the same time being able to develop whole new markets based on new innovative actuarial risk assessements not using empirical data or any past reality.

I thought about the history of new insurance systems being implemented with new concepts or technology, and wondered what happened with automobiles, and found this that fitted my expectation:

Composite Insurers

(beginning to mid 20th Century)

Large ‘Composite’ insurers were dealing with most of the motor insurance business being handled at his time.

Composite Insurers were those dealing with several types of Insurance i.e.

Home insurance, life etc. For example: whoever insured you for anything at the time you would approach to insure your vehicle as well.

There was very little competition in the market during this time.

With the monopoly in trade available the Composite Insurers pooled together all their statistics and results to devise a schedule of rates and conditions.

Each insurer had to abide by these so as to eliminate any competition. Prices were set and charged at the same rate by all the Composites.

In addition to this, all policy conditions were set the same and all discounts set the same.

I think we are seeing a similar thing with insurance and climate; we are seeing cartels and monopolies being formed. Hopefully these can be challenged by real competition. If someone insists we disallow competing insurance for human development projects because of alleged tipping points then you know you are seeing rent seeking anti-human leeches at work.

I would suggest that the concept of a mythical unknowable future tipping point is the ultimate wet dream for insurance men.

Jun 19, 2012 at 1:16 PM | Registered CommenterThe Leopard In The Basement

I remember being breathless being told that we had a 90 day window to save the world climate.

From memory, the event 90 days away that would doom the world was Barack Obama not being elected.

Jun 19, 2012 at 1:37 PM | Unregistered CommenterBruce Hoult

Paul M

It's interesting that the only tipping point in the Lenton paper that might be construed as being close on hand is the melting of the polar ice sheets.

Jun 19, 2012 at 2:05 PM | Registered CommenterBishop Hill

These are the insurance industry's records of claim payments due to natural catastrophes.

The industry has formed associations such as ClimateWise which is claimed to be the global insurance industry’s leadership group to drive action on climate change risk.

"Throughout 2012, ClimateWise will be publishing a series of 'Thought Leadership' articles. The binding theme across these Thought Leadership articles will be ‘the significance of climate change as a driver and ‘risk multiplier’ of interconnected risks, and how the insurance industry can add value to the global response."

The insurance industry uses computer modelling to assess risk and premiums from companies such as these;

Some funds such as Fermat Capital Management has over US$2 billion in assets under management as of 30 June 2011. It "manages institutional portfolios of Insurance-Linked Securities (ILS) with a particular emphasis on catastrophe bonds."

Reuters published an article about the effect of weather disasters in the US on insurance companies in April 2012:
"As weather disasters strike with more frequency, homeowners first get hit with the destruction or total loss of property. Many are then hit with the unexpected loss of homeowners insurance policies as insurance companies re-evaluate their financial liabilities."

In 2009 Evan Mills wrote a paper named, A Global Review of Insurance Industry Responses to Climate Change:
"Customers, as well as regulators and shareholders, are eager to see insurers provide more products and services that respond to the greening of the global economy, expand their efforts to improve disaster resilience and otherwise be proactive about the climate change threat."

Whether a risk is insurable by an insurance company depends on whether reinsurance companies will reinsure the risks. The premium that an insurance company can charge a customer is based in part on the premium it has to pay to reinsure part of its liability to the customer.

The industry has some $25 trillion dollars in assets worldwide. Whether the industry really believes in anthropogenic global warming or simply sees it as a scapegoat for losses due to charging premiums that were too low to cover catastrophes like floods and hurricanes is a mute point. Whatever they believe it will give them a justification for increasing premiums to build up reserves in order to pay for some future implausable global catastrophe.

Perhaps the tipping point is the point where people can't afford insurance because of the greed or failure of the industry leaving governments to use taxpayers money to pay for all the loss and damage excluded from cover once provided by insurance policies.

Jun 19, 2012 at 2:20 PM | Unregistered Commentermfo

mfo - there are three big reinsurers. One of them is CAGW-ish (Munich Re), another lukewarm (Swiss Re), the third one (Berkshire) doesn't care about global warming. Go figure.

Jun 19, 2012 at 2:45 PM | Registered Commenteromnologos

Hi Omnologos,

I agree on the need for research in 'positive' tipping points - these usually operate in social systems as far as I can see. I don't know much about them.

I also see the danger of always talking about 'threats' of nonlinearities in the climate system. I'd like to point out that my comments are personal in nature here, and obviously coloured by the fact that I have a strong interest in abrupt climate change. I would expect a policy maker to take in information from a large number of sources on this, before making any decisions.

Having said that, I think there is a strong argument that an abrupt change in climate would likely affect social and ecological systems negatively. Systems tend to be somewhat adapted to their environment, and you would expect large and fast changes to that environment to be more difficult to adapt to than slow and small ones. There are lots of historical examples of this on smaller scales than, say, the collapse of the West Antarctic Ice Sheet.

I would also like to put your mind at rest that we don't always just focus on the extreme negative case of abrupt climate change. For example, if you look at the CMIP3 model runs, most have a long and slow reduction of the MOC over the 21st century, rather than an abrupt change. There isn't a shutdown of the MOC in the projections used for UKCP09 either.

I think that 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.


Jun 19, 2012 at 2:50 PM | Unregistered CommenterDoug McNeall

Paul M,

The big question highlighted by Bish is whether these tipping points occur naturally in models. Well, the answer is that it's very easy to cook up a model that will have them in it. This is the usual problem with mathematical modelling - whatever your pet theory is, you can concoct a model to support it.

I would put some of this the other way round: The really big question is whether the tipping points occur in the *real system*. It is much more interesting when you build a model of the system from first principles, and then discover that these tipping points occur in it.

Jun 19, 2012 at 2:55 PM | Unregistered CommenterDoug McNeall

"I think that 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."

So a warning that doesn't say what and doesn't say when is going to be useful? Nothing justifies the dragging out of spurious tipping points by those whose arguments have dried up because of the lack of any detectable change. Which is not you, Doug, of course, but people abusing your work.

Jun 19, 2012 at 3:00 PM | Unregistered CommenterRhoda

re: Jun 19, 2012 at 1:13 PM | Steven Earl Salmony

This is a parody, right?

Jun 19, 2012 at 3:04 PM | Unregistered Commenterstan

Doug McNeall @ Jun 19, 2012 at 10:32 AM

Hi Doug,

Thanks very much for your very good comments!

I do have a question, please bear with me while I quickly sketch out the background. The large non-linearities get a lot of the focus (as here), but the smaller ones (for example Tsonis etc) if they exist are likely to be far more commonplace - every few decades according to those papers - and likely share the same general characteristics as the others. According to some, they are important anyway. The hysteresis, in particular, should mean that changes they cause may not readily decay, and therefore that they might provide a part of a general explanation for decadal variability. Having said all that, I'm very much on the lookout for papers or arguments that demonstrate this picture is incorrect or otherwise illuminate it. So my question is, can you point out to me anything of that kind?

PS: Possibly your paper contains some of what I’m after, in which case please just say that, and I’ll read it when I get my copy from Richard.

Jun 19, 2012 at 3:22 PM | Registered CommenterPhilip Richens

Hi Omnologos
I agree. It's a puzzle trying to figure out what insurance companies actually believe.

There have been very mixed messages coming from these large insurance companies. I don't know what to think. But Swiss Re has popped up at Rio+20. They have signed "The UN Principles for Sustainable Insurance", which is "a global sustainability framework and initiative for the world’s re/insurers to manage various global challenges, launched 19 June as part of the UN Conference on Sustainable Development in Rio de Janeiro (Rio+20)." Michel Liès, Swiss Re Group CEO has even given a little talk which is on video:

Munich Re is another enigma. They have in the past been ambivalent about global warming but now they even have a whole topic devoted to climate change on their website:

Personally I think insurers are now coming under pressure to be seen to be promoting the "correct" message. They will probably do so because they consider it good for business. I've never known an insurance company do anything which wasn't connected with making ever larger profits.

Jun 19, 2012 at 3:24 PM | Unregistered Commentermfo


The comment you noticed has appeared on several blogs. There are a couple of really nice responses over at Ben Pile's place.

Jun 19, 2012 at 3:29 PM | Registered CommenterPhilip Richens

Tipping points are typical behavior in nonlinear dynamical systems; specialists often refer to them as bifurcations. If you are studying a nonlinear dynamical system, you should expect to find tipping points. And just a reminder, whenever you see the word "nonlinear" think "real-world."

Roger Pielke Sr. has some excellent information on why climate is a nonlinear dynamical system, or as he sometimes says, climate is an initial value problem.

When a nonlinear dynamical system (or a model of same) reaches a tipping point, the rules change. For example, ice might disappear, so the rules defining albedo in those areas should change. Often when the rules change, there is hysteresis. If for example the system passed a tipping point while CO2 or solar forcing was changing, the system probably will not return to the earlier state if the forcing is only dialed back to what it was just before tipping. Because the system is different after tipping, the forcing will probably need to be dialed way back to a value well before where tipping occurred in order to return to the earlier state (e.g. with ice present). An example would be entering and exiting an ice age: in order to exit an ice age, the Milankovitch forcing needs to get much stronger than it was upon entering, to make up for all the sunlight reflected by the expanded ice.

Another example of a possible climate tipping point was provided in research Wallace Broecker did (Science, 1997) on the thermohaline circulation, noting that a change in fresh water flow into the North Atlantic could shut down the thermohaline circulation. As I recall, a program of measuring the thermohaline circulation (in the northeast Atlantic, I believe) was initiated; first results indicated some cause for concern, but later results were more reassuring.

Whenever one speaks of the climate system switching from one mode to another (ENSO, PDO, AMO for example), there is probably a tipping point involved. If you believe in things like the PDO and AMO, you should believe in climate tipping points. (Note this does NOT mean that a change in PDO mode is necessarily catastrophic; it only means the change may be harder to undo than you might think.)

The problem with GCMs is that there is no evidence they get things like PDO and AMO right; more generally, they do not capture the nonlinearities well. Again see Pielke Sr. for more information.

To summarize, a tipping point is an abrupt change which is sticky, i.e. difficult to undo. Climate is a dynamical system in which nonlinearities are important, so tipping points are to be expected. It is no good claiming that tipping points are a wrong concept for describing climate. The real problem is that tipping points undoubtedly exist in the real climate system, but the models are not good enough to characterize or understand them.

Examples in simple prototypical dynamical system can be found in the book Thompson and Stewart, Nonlinear Dynamics and Chaos, esp. Chapter 13 where tipping points are referred to as dangerous bifurcations.

Jun 19, 2012 at 5:44 PM | Unregistered CommenterBruce Stewart

Bruce, no problem with the existence of tipping points, that's a given. No problem even with the inability of current models to predict them, that a limit of current knowledge for sure and perhaps mathematical possibility.

The problem I have is the use of tipping points as bogeymen by people who should know better in order to push a political agenda. That is dishonest as well as desperate.

Jun 19, 2012 at 6:00 PM | Unregistered CommenterRhoda

Surely if tipping points actually existed, the earth would have long ago tipped irreversibly into one of those spirals of doom. The evidence suggests the earth's climate is incredibly stable, albeit with a propensity to oscillate between temperate and very cold periods, which is linked to the orbit of the earth around the sun, and the movement of the earth on and around its axis (hence linked mainly to incident solar radiation from the sun). CO2 concentrations have been much higher in the past, yet here we all are, with a stable climate.

As others have pointed out, the data suggests that the negative feedbacks operate more forcibly than any hypothesised but as yet unobserved positive feedback factors, necessary for any 'tipping' point to be reached. But I'm sure hypothesising tipping points (and then getting your environmental advocates in the press to turn it into a nice scare story) is a good route to more grant money...

Jun 19, 2012 at 6:13 PM | Unregistered CommenterDJ

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