Open invitation

I've frequently argued that there are reasonable and rational people out there who are nonetheless skeptical about the AGW, IPCC, Policy nexus, and that it is worthwhile trying to engage in sensible to-and-fro on these matters. Many of my co-bloggers disagree, and think that giving air-time to trolls is counter productive.

So, in response to a thread on the Guardian today where my comments suddenly and inexplicably got moderated out (not the first time this have happened, though I don't know how I breached the community guidelines), and response to persons such as Fernando Leanme, who frequently pops up with things to say, some which are very nearly interesting, and who seems like a decent chap at the bottom, if I really have found his blog, please come and make your case here.

I have my own opinions and prejudices; show me why I am wrong. Explain what I seem to be missing. Give your own opinion and your reasoning.

I won't moderate comments unless they are truly offensive or illegal. I'll even tolerate obvious trolls for a short time, but since the aim is discussion, people who have nothing to contribute will probably get left behind, eventually.

So, please comment...

Whether the weather, whatever...

So it's back to a familiar pattern - the weather hits the news, and discussions arise about climate change, impacts, causes (blame), and so forth. In a sense this is good, because it brings climate to front and centre in the public consciousness, but I have a concern about it. I think it is leading us down a tricky path.

It's no surprise that weather extremes are used as tools to advocate for action on climate, since the impacts are immediately visible and present to the consciousness of the public in a way that no amount of good science or statistics can ever emulate. It's the time when people just 'get it' more readily. It's evidence by ostensive definition; 'Look!'.

The problems I have with this: first, the obvious one, that it perpetuates the language of 'cause' or 'blame'; the notion that any given weather extreme is caused by a changing climate, or evidence of a changing climate. No. It might be evidence of what happens when the weather systems of a globe or region don't do what they normally do. It might be cited as an example of what sort of damage and suffering might be expected if weather patterns change in particular places. But it is not the reason why scientists, working with long-term statistical averages, are worried about the direction we are going in. It's also, arguably, not a good precedent for future events.

The desire to get the message across, that changing climate has significant impacts which are likely to hurt us, is of course important. But a changing climate and the long-term consequences of this are much more than the sum of a series of damaging extremes in local or regional weather. So I feel that to work this particular meme, this message, is potentially dangerous. In our eagerness to get folks to pay attention, we might be skewing the real importance of what is happening to the planet and our role in this.

It will be interesting to see how the WG3 section of the AR5 copes with this apparent contradiction - that the urgency of action is demonstrable through known, visible impacts, but that the reason for concerted international effort goes beyond these impacts. Consistently, scientists have been at pains to point out that the likely consequence of AGW of more than 2 degrees is 'dangerous'; 'Dangerous Climate Changes'. 

But the dangers are not just about what happens to weather patterns in line with what we already know and can see, or measure. More worrying is the danger arising from our ignorance or uncertainty - in other words, runaway feedbacks, system-wide effects (what price a permanently accelerated jetstream, or a shutdown of the THC/AMOC?), and simply unknown effects which are only hinted at now, but would, if they happened, have really frightening consequences. I'm thinking here, for example, of what happens if, as a result of pollution and drought, insecticide and shifting wind patterns, we lose 95% of the Global honey bee population?

In simplest terms, the dangers we should be worrying about are those about which we are uncertain, but which have a logical relation to what has already been observed. To steal a phrase from a well-known Nobel scientist, what should draw our more serious attention is that the impacts of increasing atmospheric CO2, increasing deforestation, increasing black soot deposition and increasing abuse of natural ecosystems, will probably be more than we currently imagine, and different. 

Though I am reluctant to push this to the absolute extreme, the argument here is that, if the sum of the impacts of our present stewardship regime (bad joke) of the Earth are 'more and different' to what can happen within current parameters, then we really are setting ourselves up for a Global (social) transformation a couple of step-changes beyond what is currently being considered in 'mitigation and adaptation' scenarios. And we aren't in a position to anticipate these. Yet.

Which takes me at last back to my gripe. Focussing on weather extremes is short-term. Focussing on economic damage is short-term. Focussing on the evidence before our eyes is too narrow a view. If climate change is about anything, it's about the bigger picture. If sustainability is about anything, it's about the bigger picture. The value of a wood is greater than the sum of the value of each tree; the importance of finding a way to reduce our impact on our planet lies not in saving trees, or woods, it  lies in avoiding the awakening of the Kraken, of arousing Godzilla, of unleashing the rough monster that slouches towards Bethlehem to be born; it really is about keeping nightmares in the realm of the unreal.

For everything there is a season - tide and time

Over at the warren, Uncle Eli has posted about SLR, a subject I touched on last month, here, and here, including references to Grinsted's excellent material.

It occurs that the Average Josephine (IOW, most of the world) might look at the projections of sea level rise and, whilst registering that a change will have an impact, might reasonably ask why a meter or so of extra sea might be such a big deal. So here's an attempt to place this into a 'human' context.

On its own, a few centimetres of water 'added on' to the water level at any given beach or dockside is no big deal. This is because the other forces which have an effect on sea level at any given location are much stronger (they create more variability) than the underlying 'signal' of sea level.

First and most obvious is the effect of the tides. Whilst in some places sea level fluctuates by a few metres over the course of a day, in others the tidal range can top ten metres and more (up to around 15-16 m for some locations). In practical terms, coastal human habitation and business takes this into account, so in most places human activity takes places above the high tide level, for obvious reasons.

At certain times of year, specifically the Equinoctial Spring Tides, the various forces which interact to create tides and tidal ranges combine to create particularly high and low tides. It is not uncommon already for these to overreach the human adaptation level and to result in localised flooding, which is further worsened if these tidal periods occur in sync with strong weather conditions (in particular, depressions, often related to storms).

Now, the current range of projections for changes in sea level have to be considered in the context of historic tidal ranges and existing infrastructure and human-ocean interfaces.
For example, the 'averaged' sea level range globally hits around 79cm during Spring tides. This means that, overall, the shoreline would experience a few extra inches more or less. But in a local and regional context this 'average' is effectively meaningless, and is not reflected in the real experience of many coastal dwellers. For most people on coasts, the tides go up and down several metres.

If global average sea level rises by, say, half a metre, what does this mean for local impacts? And what effect does this have on local tidal ranges and, in particular, during the upper bound of the ranges (the Equinoctial Springs) and those occasions when these coincide with storm surges?

Well, it should not be difficult to work out that an extra 'average' SLR of 50cm is going to mean a rise of high tides, and of high springs, in the order of 2 - 5 metres of 'extra' sea. Given that a storm surge can increase sea levels (for example, in the Philippines) by another 4-5 metres, and you end up with places which are likely to experience regular (annual or more frequent) tidal surges in the range of 5 -10 metres. We have seen the horrific effects on one part of the world where a tidal surge of 5 metres, added to extreme weather conditions, has resulted in devastation and carnage. Now multiply this by all those places which are 'vulnerable' to such variability.

As an aside (because I'm not certain of the projected effects), it should be noted that a Spring tide normally produces currents twice as fast as Neap tides, but with eight times the power, or force. Anyone who has struggled to get out of the water onto a beach during an ebb in difficult conditions can have a sense of how much power is involved - it is, literally, an overwhelming force. 

It seems rational to presume that higher Springs will be associated with faster currents and therefore greater forces - resulting in more erosion, more localised damage and greater stress on infrastructure (including defences). So, the effect-multiplier of a few centimetres of extra sea level 'on average' produces impacts which can easily be seem to include, for example, the overwhelming of low-lying islands, or the inundation of coastal cites, oil refineries, nations (Bangladesh).

If all of this is the consequence of half a metre of sea level rise, what then is the consequence of a metre or more? Is it likely to be twice as bad? Or, given the 'effect multipiers, are we instead talking about a localised effect with a difference of an order of magnitude?

Finally, for the economically-minded amongst you, remember that an astonishing proportion of the world's trade is conducted across the oceans - around 90% of all trade goods is shipped at some point. Now, consider the impact on shipping of the changes outlined above. The cost of building tougher ships, the cost of building new, relocated shipping hubs (the World's three deepest 'ultratanker' and supercontainer ports are all vulnerable to rising sea level). The risks and losses, all to be paid for by someone.

A very high proportion of the Global population lives in the coastal strip - I think it's about 85% of the population. Not all of these people would be vulnerable in the way I outline above, but with sea level rise must come, inevitably, relocation and mass urban movement inland, fundamentally changing the dynamic geography of our society.

That's why sea level rise matters, and why a metre is more significant than half a metre.

NOTE also Simon Donner's eminently pragmatic contribution to the discussion of adaptation.

What are we going to do now, Mr Milligan?

The initial source material and reporting of the presentation was described earlier, but now it's going more mainstream, I suppose it's time to consider:  http://www.newstatesman.com/2013/10/science-says-revolt .

Picked up also at Skeptical science weekly round-up.

The appeal, of course, is that a scientist, Brad Werner, had the nerve to stand up in front of peers on the back of a presentation entitled 'Is Earth F***ked?

And then answered the question. His answer was 'more or less'.

I spent some considerable time researching Climate Science before, during and after the IPCC AR4, the ICARP conference on the Cryopshere, and the Stern Report, a few years back now. At the time, the discussions were about the same as they are now, a few years down the line, but there are changes.

Read Ostberg et al, Mora et al, even Tol, or the Norwegian Met office report highlighted this week on RC (here). Read the AR5, insofar as it has yet been completed. There's almost immeasurably large amounts of really quite bad news, about oceans, global warming, sustainability budgets, water, heck, practically everything you might want to consider when looking at the Big Picture points inexorably towards Werner's conclusion.

For 20 years (arguably longer) every government and major financial institution and source of power (the large corporates, etc), has know the path we were walking down. We've all known it, though some step aside and disavow. And the heartbreak is that absolutely nothing of significance has changed. This is not because there has been a lack of effort - lots of people in lots of arenas and disciplines, even some governments, have tried to walk the narrow path of responsibility for stewardship. But these efforts have been overtaken by the relatively rapid growth in the global economy from the opening of new resource and market opportunities, amongst other things.

So, let's presume that, for the sake of argument, Earth is, more or less, F***ked. Whatever we decide collectively to do from now onwards will make some difference, and some important decisions on the larger scale will make a substantial difference, but in spite of this, in the next 100 years the world will change. (yes, this is a truism, but...)

If this is the case, then the BIG Question now, and the one which could be said to underlie all the stuff about mitigation and adaptation,  is 'What kind of World do we want to aim for?' The secondary, and no less significant questions, being: 'What are we willing to pay for it?' and 'What types of extreme nastiness are we able to tolerate, and what must we avoid regardless of other consequences?' Other fairly obvious questions spring to mind.

If you are unused to speculating on possible future human/earth scenarios, then you could do worse than read 'Earth Abides', 'The Sheep Look Up', Oryx & Crake (and the rest of the Atwood Trilogy), a range of 'cli-fi', or even George Orwell. You might rediscover Lovelock's tragic vision, or make your own up. It would be interesting to know if any of you readers come up with scenarios more positive than the ones I have imagined recently.

As things stand, whether or not global warming is the elephant in the room, the current political reality is that justifying any environmental policy or action on this basis is hard for governments to swallow right now. Maybe things will change for the better in the future (huh!). So, my first suggestion is that we look hard at the things which have an impact on global climate and environment from the point of view of the whole shebang, earth systems, and see what actions or policies can be made now, in this political environment, which would both improve the general state of the earth system and, coincidentally, help to mitigate severe adverse climate change.

Much more on this later.

I can't believe we're on the eve of destruction

Picking up on a couple of pieces of editorial in the Guardian recently, both by Adam Corner, gives me the opportunity to cover two matters which I think are important. The first concerns changing our World for the better here, "Morality is missing from the debate about sustainable behaviour" and the second, "Will the IPCC start a new conversation about climate change?", here .

Reading the comments to the latter piece it was interesting to note that many of the responses were about responsibility, crisis, protection, danger; familiar themes in climate change dialogue, and the common subject for accusations of alarmism. Here is my contribution to the comments thread:

Fear need not be the overriding 'necessary' response to climate change. To an extent it plays into the hands of those unwilling to face the reality of change; it's just too easy for them to cry 'alarmism' or simply go into denial.
The IPCC was formed to help all governments understand and address the risks which were first identified twenty years ago. What have governments managed to achieve in this time? Some are trying, most are failing.

The fact that our world is changing almost faster than we can comprehend should be recognised as a simple reality. But it is also an opportunity. We can see from countless bits of evidence that we have placed ourselves in jeopardy from the historic indifference not just to the climate but also the environment and ecology of the planet. We know the relationship between our past choices and present predicament.

So now, being able to see what has been and see what is likely to be, without decisive action, we have an opportunity. Our generation can (should?) shape the future that we choose; we can let the slide into the mire continue, or we can choose to envision a better way of living within our planet and get off our arses and do something about it.

Don't be afraid. Be determined.
The first Guardian piece is really about the reasons we have for making a change in our personal lives. Corner proposes that most lasting behavioural change comes from internalisation and decision based on ethical foundations. He also points to the ineffectiveness of purely 'money-as-value'- driven arguments for action. These are the ones which assume that we are stuck in the 'sixties presumption that all the Public cares about really is the 'pound in their pocket'.

It was interesting to note the creation in September of a new think tank,  The New Climate Economy. Read the 'about' section to get a sense of the undoubtedly valuable mission the organisation has. But the organisation suffers from the same fundamental problem shared with much of the Political debate on climate change - it presumes that the ultimate motivation for any future action must be self-interested, and (for politicians and corporations) that variations of cost-benefit and risk assessment analysis are the way forward, since their content is ostensibly measurable.

And so I think that the New Climate Economy is missing something - in sticking to the presumption of the pre-eminence of Economy over other elements of the sustainability circle, it will no doubt do much to counter the pseudo-Lomborgian 'Climate change mitigation is a waste of money' argument. But it won't stimulate sustained behavioural change without a heart. As Corner suggests, that heart needs to be fundamentally ethical, based on values other than economic ones. Then, the language, the communication and the call to action will have a more powerful response.

We should recognise that, in important ways, the way that modern human society works has resulted in disproportionate power being placed in the hands of the bean-counters and their lawyers. And whilst their role and contribution to development, change management and future-building is both important and valuable, I would leave you with the questions: Are these the (kind of) people who we want to shape our future World? If they are already just too powerful to replace, what can we do to restructure both climate and sustainability thinking in such a way that their role is less about the why and more about the how?

Because the why matters.

Reasons to be cheerful, one, two, three

Back to the AR5 on the subject of the Antarctic, and in particular the Marine Ice Sheet Instability Hypothesis. The AR5 confidently asserts that 'it is likely that abrupt and irreversible ice loss from WAIS is possible'. Why does this matter? Because if it occurred, that additional sea level rise which the AR5 does not expect, of 'several tens of centimetres', would become a reality.

For non-scientists, (usual warnings apply), a 'sudden and irreversible ice loss' refers to the possible 'collapse' of the mechanism which currently constrains the export of ice into the oceans and therefore the contribution to sea level rise. This would be signalled by rapid, non-linear changes to the Pine Island Glacier (PIG) and Thwaites Glacier (TG). These two represent a substantial proportion of the potential sea-level contribution of the WAIS, which is why they are important. One of the keys to recognising that a sudden process  is under way is the retreat of the Grounding Line (GL) of the glaciers. Recent research suggests that Pine Island is more risky than Thwaites because of the relative basal geography of the two.

The process follows a theoretical sequence: The glaciers at the sea end thin, meltwater seeps down from above, the glacier fractures deep into the outlet section, then collapses; the glaciers behind speed up, pushing more ice seawards, and the grounding line (where the sea can no longer get 'under' the glacier, retreats inland. 

In Chapter 13, The AR5 discusses the condition under which such an event might occur and the consequences:

"Two processes that could trigger GL retreat are particularly relevant to contemporary polar climate change. The first is the presence of warmer ocean water under ice shelves, which leads to enhanced submarine iceshelf melt (Jacobs et al., 2011). The second is the presence of melt water ponds on the surface of the ice shelf, which can cause stress concentrations allowing fractures to penetrate the full ice-shelf thickness. This process appears to have been a primary factor in the collapse of the Larsen B Ice Shelf (LBIS) over the course of two months in 2002 (MacAyeal et al., 2003). The collapse of the LBIS provided a natural demonstration of the linkage between the structural integrity of an ice shelf and the flow of grounded ice draining into it. Following the breakup of LBIS, the speeds of the glaciers feeding the collapsed portion of the shelf increased two-to-eightfold, while the flow of glaciers draining into a surviving sector was unaltered (Rignot et al., 2004; Scambos et al., 2004; Rott et al., 2011). This indicates that a mechanical link does indeed exist between shelf and sheet, and has important implications for the future evolution of the far more significant PIG and TG systems of the WAIS."

In addition to any other, earlier material, a new paper in The Cryosphere describes Condition One:

Dutrieux, P., Vaughan, D. G., Corr, H. F. J., Jenkins, A., Holland, P. R., Joughin, I., and Fleming, A. H.: Pine Island glacier ice shelf melt distributed at kilometre scales, The Cryosphere, 7, 1543-1555, doi:10.5194/tc-7-1543-2013, 2013. There are other observations and calculations substantiating that there is water under the PIG, that it is relatively warm, that it is progressively undermining the glacier. There seems little reason to doubt that this condition is currently being met. 

Condition two requires the presence of meltwater at the top of the glacier. I can't find the source (maybe someone can help), but I am certain that I have very recently seen a record of observation of this phenomenon - I believe it was at the Thwaites Glacier, but there is no reason to suppose that the phenomenon would exist at one glacier and not the other.Forthcoming papers (not yet published) look at the 'condition' of PIG and seem to offer further evidence that the conditions exist for a full-depth fracture of the PIG.
So; it would appear that the required conditions for the fracture and subsequent collapse of the Pine Island Glacier are being met. If this is correct, the next 'critical' stage would be the appearance of a glacier-wide fracture, probably during the Austral Summer. On the surface, it very much feels like this is no longer a matter of 'if', but of 'when'.

Prediction a non-linear shift is, of course impossible. It has to be a sophisticated form of educated guesswork as to when this could occur. To me, given that other indicators suggest that the transformational process in the cryosphere are systematically understated in the 'official' lines, it could as easily be this Summer, or ten years, or twenty, thirty years away.

If any of my readers can give guidance as to the plausible timeline in which we are working here, it would be much appreciated. Likewise, if someone thinks that I am misrepresenting or overstating the case. But from the viewpoint of this blogger, that 'likely that it is possible' statement of the AR5 goes nowhere near capturing the reality of the situation or the risk. As a consequence, the decision to eliminate sea level rise estimates which incorporate a collapse in the 21st century look at best misguided, at worst, much too conservative.

I'll look out for other connections on the subject: for example, Aslak Grinsted's excellent summary of the estimates, and RealClimate's ongoing discussions.

I think this is a real, substantive risk which has a significant timeline for the current generation, and that serious and urgent investment in Antarctic research is now essential.

Girl, there's a better place for me and you..

Reading Lord Ridley's letter to the Guardian a couple of days ago, my first response was to wish to be critical of some of the assertions within. This is because his expressed views, on first reading, tend to clash with mine on certain significant matters.

Fortunately, I took a little time to do some background research. The origin of the letter is a response to Bob Ward's somewhat acerbic inclusion of Ridley's supposed role in the GWPF's 'campaign' to undermine the AR5 in advance. The Ridley article is paywalled at the Times, but a copy is on his blog. In it, he argues that the 'climate debate' has become too polarised and a 'third way' might actually be more constructive.

So far, so good: I also believe that the debate has polarised - it was always adversarial, but in my original blog, Old Man in a Cave, I sought to encourage a more 'open' kind of response to what I believe is genuine uncertainty amongst the general public (of people not trained in science) about the significance and meaning of climate change. In the intervening years it seems to have hardened further. I, too, believe in a 'third way', but for different reasons.

I also note that much of Ridley's argument is a reiteration of his previous article, in May, which was analysed, criticised and discussed in detail at the time - there seems no point in going over that old material. For the record, I am satisfied that Lord Ridley is a sincere person who is expressing an opinion based on a genuine interpretation of a substantial amount of research and previous discussion. He means what he says and doesn't view this as being any part of a 'conspiracy', rather it is, to him, a reasoned and reasonable response to the evidence as he has interpreted it. No doubt some will think I am naive, but I prefer to think of myself as 'accepting' - I will presume the good intentions and sincerity of others as far as is possible, unless it becomes evident that the other in question refuses to reciprocate.

There are so many avenues of discussion arising from Ridley's article and other writings, but I will focus today simply on the content of the Guardian letter, and consider two questions: firstly; are we right (him and me) to argue for a depolarisation of 'the climate debate'? Secondly, what is it in his letter that makes me feel that we are potential adversaries?

The letter's opening statement contains the first ticking timebombs of potential disagreement:

"In his continuing attempt to polarise the climate debate into believers and deniers, Bob Ward has resorted to conspiracy theories and attacked me..."

For someone seeking to promote a 'honest debate' this might not be the best way to start.

To a hardened climate science enthusiast, this reads as a characteristic 'role reversal' strategy - let's establish who is the 'attacker' and who the 'victim'; it is the 'alarmist' who is attepting to polarise the debate, and the 'alarmist' who is resorting to conspiracy theories.

It doesn't take very long for an intelligent and curious reader to find endless examples of 'attempts to polarise' and 'conspiracy theories' in the climate debate, but historically these domains have tended to be occupied far more by so-called 'denialists' than by their adversaries. I personally think that the successful polarisation (and subsequent politicisation) of GW discussion has been one of the more significant achievements of those who have consistently advocated or pursued inertia as the best response to climate change.

Since this kind of role-reversal is a familiar strategy in the climate change rhetoric it is easy to understand why an experienced reader might immediately assume that all that follows is going to be another example of obfuscating, procrastinating disinformation. Which means that a reader like me is already predisposed to find fault with the content. Which is a successful polarisation. If I am provoked, my 'human' response is to become and adversary, and so the game goes on. This doesn't feel like we are setting the grounds for an 'honest debate'.

Next, the letter goes on to cite Tol:

"Professor Richard Tol's 2009 summary of 14 separate studies found that there is likely to be net global benefit to human or planetary welfare from warming till temperature has increased by 2.2 degrees from 2009 levels, which is about 3 degrees above pre-industrial temperatures. This is before taking adaptation into account so it is conservative."

This is important because it forms the foundation of much of the following argument. To me, it is worrying because it suggests that much of Lord Ridley's opinion is founded on Tol's analysis, from his paper of 2009, for example. I have no doubt that others have pointed out that Tol's analysis has its critics, and that some have argued that his principal argument contains flaws and the dependent conclusions are thus called into question.

It also seems to suggest that this particular analysis has greater weight to Ridley than others by such as Stern (2007). A cynic might observe that we are disposed to accept the evidence which tends to support our pre-existing prejudices and prefer them to evidence which contradicts them, and suggest that this may be what is going on here. I know this is true for me, though I do try to be self-aware about it.

But I suspect that it is the final section of the letter, which is so dependent on the validity of the Tol position, which really got me ticklish:

"Millions of people are currently being driven into fuel poverty, hunger, malnutrition and respiratory ill health by today's climate policies. Mr Ward appears to think they should be ignored in favour of concern for the welfare of wealthier people in the next century."

The first of these two sentences is, to me, deeply misguided. I cannot think of anything I have recently read which could possibly support this statement. It runs so counter in every respect to the material I have read on the subjects concerned that I feel inclined simply to assert that this is not true. I'm not claiming it is a lie, only that it is wrong, a false assertion. And I believe it would be so irrespective of whether it depended as it does on the unproven assertions of Tol.

The second sentence raises a matter which I do believe is a genuine conundrum: what value do we place on the interests of future generations in relation to the present generation and how do we measure this? It doesn't help that it has been phrased in terms which are once again likely to provoke polarisation, rather than 'honest debate'. But it also looks at least superficially that Ridley has already made his mind up on this, and that he does not think there is sufficient evidence of substantial future harm at a level which would justify present investment (no, not sacrifice or suffering, but investment).

A finishing point. Debate is an interesting phenomenon. I used to do a lot at school. It is the basis of procedure in Politics, especially the two-party model, and in Law. It is a potentially valuable and useful tool for reaching a Hegelian Synthesis from a thesis and antithesis. But it is fundamentally polarising. It presumes adversarial interaction. The procedure is not dialogical but rhetorical. I do believe that open, honest interaction between people is the 'third way' to address both private and public engagement in the issues of climate change. I am not convinced that 'debate' is the best tool for the job.

None of the above should be read as suggesting that I am defending Ward or attacking Ridley. I am presenting my own reaction, partially deconstructed, of what I read and how I reacted. Ward and Ridley are big boys, they can resolve their own differences.

Sea Oddity - it's a godawful small affair

Well, RC went and stole a march by posting about chapter 13, and deservedly their material will get more attention because the contributors are specialists in the area. But whilst they discuss some technical matters, they don't seem to have covered some of the 'oddities' which, to my eye, point towards an innate conservatism in the Sea level rise assessment. Since RC has done it I will also, after all, use some of the draft, but will try to do so sparingly. Interested readers can read it for themselves.

As usual this is the 'outside' view, so I expect (and hope) for feedback.

First up is the paragraph about the two model intercomparison papers, Bindschadler et. al. (2013) and Nowicki et, al (2013), which concludes:

"The resultant projection included contributions from lubrication, marine melt and SMB-coupling and generated a mean SLR at 2100 of 162 mm over five models, or 53 mm if an outlier with anomalously high response is removed (including SMB results in SLR at 2100 of 223 and 114 mm for five- and four-model means, respectively). This comparison lends further weight to our confidence."

I don't have a problem with the concept of removing outliers as such, and it is clear from the very large differences in results that the outlier must be well out, but if they are included in the model intercomparisons, should they not be included in the assessment of the range? My beef with this is that they seem to be saying that once they have fiddled a bit with the original papers (and I'll admit, I might also be inclined to discount an outrageous outlier if there was no sensible reason to consider its' plausibility), they end up with a number which adds confidence to their 'chosen' assessment range. This doesn't seem, on the surface, to be entirely transparent.

Next up is the 'introduction' of the Marine Ice Sheet Instability material:

"There is an underlying concern that observations presage the onset of large-scale grounding line retreat in what is termed the Marine Ice Sheet Instability (MISI; Box 13.2), and much of the research assessed here attempts to understand the applicability of this theoretical concept to projected SLR from Antarctica."

Now call me a pedant (it's a reasonable charge), but the language chosen: 'this theoretical concept' at this point, whilst it may be technically correct, might predispose a reader to imagine that MISI is an implausible scenario. Later on, the Chapter includes the memorable:

"In summary, based on ice-dynamics theory, numerical simulations, and paleo records, it is likely that abrupt and irreversible ice loss from WAIS is possible. However, theoretical considerations, current observations, numerical models, and paleo records currently do not allow a quantification of the perturbation that is necessary to destabilize the ice sheet."

Can someone tell me what that first sentence means? It's a cracker.

Last up for this post is what appears to my eyes to be mildly remarkable:

"More detailed regional modelling using scenario A1B illustrates the potential for warm water to invade the ocean cavity underlying the Filchner-Ronne ice shelf in the second half of the 21st century, with an associated 20-fold increase in melt (Hellmer et al., 2012). Based on the limited literature, there is medium confidence that oceanic processes may potentially trigger further dynamical change particularly in the latter part of the 21st century, while there is also medium confidence that atmospheric change will not

affect dynamics outside of the Antarctic Peninsula."

Wow. So there is another hypothetical process that indicates a possibility of a larger potential sea level rise, which includes local changes in orders of magnitude. Does this not indicate that the reasonable range of SLR might be upped a bit? After all, we are talking about a range, aren't we?

I'm going to finish this off in another post because I am tired.

Comments, please.

Little by Little

After the last IPCC (AR4) I spent some time on the available literature as well as conversing with several qualified people (scientists) and concluded (purely on the basis of how it all seemed to add up), that the AR4 estimates of sea level rise (SLR) probably were conservative and that a rise of around a metre by 2100 was a reasonable estimate, that 1.5 metres was plausible, but that much more seemed unlikely in the timescale, given the range of evidence.

Having gone through chapter 13 of the new AR5, I am steadily moving towards the view that a metre by 2100 is possibly the lower bound of SLR, that 1.5 metres is now the reasonable estimate, and that a larger rise is not so much unlikely as uncertain, which is a very different thing.

Of course I'm not allowed to print the stuff (well..) in the draft itself, but I extracted some parts, particularly in relation to the contribution to Sea Level Rise of the Antarctic Ice Sheet and the Greenland Ice Sheet, thinking to comment as a whole. But there is too much - even reduced to the bits which seemed most relevant to the dialogues here and on other websites.

In addition, there are plenty of better qualified commentators already working on this in the public domain. Thanks to Steve Bloom, who provided these sample links (you will need to expand the comments). This is also thematically connected to the discussion of the cryosphere (Chapter 4) here.

What I wanted to draw out of the AR5 were the potential reasons why others might think that their assessment is conservative. I have come across 9 slight oddities which will be dealt with a bit at a time (otherwise it's just too much). The first one concerns the basis for estimating the SLR contribution from the Antarctic.

It looks to me as if the core statement of estimated likely SLR from this source is based on Little et. al. (2013). [NOTE - the Little paper in question is behind a paywall at Nature Climate Change, but available as a pdf via Google Scholar] Actually, that's what the report says. But then it goes on to say, apparently, that the reason for choosing this as the reference point is that it's somewhere in the middle of the available ( process model-based) assessments, not including outliers (!) , and not taking into considering semi-empirical model estimates. But this is undermined in the selfsame explanatory paragraph by stating that it falls at the lower end of the estimates from the other process model-based assessments which were available. [NOTE - the Little paper in question is behind a paywall at Nature Climate Change, but available as a pdf via Google Scholar]

It's important to remember that the people who put this stuff together for the IPCC are experienced professional scientists and they work very hard to present what is the representative view in a balanced way. Yet, throughout the chapter, there are side-comments and minor details which, put together, strongly suggest that their chosen rubric is a consciously conservative one. 

The other point which is frequently being made is that this is an example of over-dependence on the process models. There is enough evidence in the chapter to support this view, some of it overt. As things stand, I am inclined to think that not enough weight has been given to either the semi-empirical models, which consistently produce SLR rates higher than the process models, or to the people on the ground, who also seem consistently to question the AR5 estimates and suggest they are understating things.

As was pointed out to me, the most important source of difference between estimates of sea level rise is the Antarctic. Why? In broad terms, the contribution from other sources, such as the Greenland Ice Sheet, can be imagined as adding to SLR in a way comparable to the way a tap adds water to a bath, steadily. With Antarctica, this is also the case, but there also is an identifiable (but uncertain) risk that someone is planning to jump into the bath - via a destabilisation of the West Antarctic Ice Sheet (definitely more on this in a later post). The analogy also works when we think about the proposed timescales for change. There's a huge difference between adapting to a slightly overfilled bath by being careful, and clearing up after the idiot went and jumped in.

There is a lot more to be said on this subject, suffice it to say for know that I am now more concerned, after reading the report, than I was before, about the ability to adapt to some of the possible changes in the next forty-odd years, and even more worried about the following half century.

Might as well try and catch the wind

Today in the Guardian and on the Skeptical Science blog John Abrahams writes about a new paper by Mora et. al. (same article) about the timing of climate change impacts. At the same time, ScienceDaily covers a new paper by Ostberg et. al.: Critical impacts of global warming on land ecosystems. 

By coincidence I came across the latter yesterday and was already preparing to write about it because I found the conclusions both interesting and important. The Mora paper is behind a paywall, but the Ostberg one is Open Access, here, thanks to the excellent EGU-supported Copernicus.org (link in sidebar).

We can't directly compare that articles unless we subscribe to Nature (which I don't), but we can compare what is written about them, and consider one or two other points related. The ScienceDaily review is a reasonable summary of salient parts of the paper, though I would possibly have had a slightly different focus had I reviewed it directly. I must presume that the Abrahams review (along with the Abstract) also gives us a reasonable summary.

A couple of things are quite striking immediately, though. Both papers use models to look forward to environmental change out to 2100 in response to AR5 scenarios. Both reach very similar conclusions, through different methods, about the timings connected to changes. Both indicate that we are already along a pathway to changes which cannot now be diverted, even with radical mitigation.

Not surprisingly, Mora and SkS/Guardian focuses on the Climate - the word is used 20 times - and climate extremes (the subject of the paper). In contrast, the Ostberg paper focuses on ecosystems. Though I write mainly about climate change myself, I find I prefer the Ostberg et. al. approach much more compelling (not least because I can actually read the material). 

In part this is probably because I am not comfortable with the focus-shift in the entire agenda to climate/weather extremes. My suspicion is that this has in part been driven by the (correct) historical perception that neither policy makers nor the general public was getting the point of climate change, and also driven by the fact that weather extremes have a measurable economic cost, and there has been a general shift towards placing economics at the centre of the sustainability concept, a shift with which I have profound concerns.

My reaction, though, is probably mainly driven by my ability to grasp and imagine what an ecosystem change might actually look like, whereas I struggle to conceptualise and visualise what a climate change might look like, beyond the obvious weather extremes, which, coincidentally, I don't see as the most important aspect of climate change.

Which leads me to what may be a the spark of an original thought. The air is invisible and often intangible. The earth (ground) is the opposite. As human beings we engage with the immanent far more readily than the insubstantial. Is climate change 'resisted' by many members of the public for this reason -it is just too difficult to 'grasp', literally?

There is so much more to be said about these pieces of research and the collective message they give, independently, about where we are going and what it might look like, but for now, I can only recommend that you read the Ostberg et. al. paper (it is not 'too' mathematical for a layman to get to grips with) for yourself, and consider whether it matters that we mitigate future climate change impacts now.

Postscript: The Mora paper has been widely picked up in the media, less so the Ostberg. The Daily Mail response, found after trawling down through endless z-list nonsense, is a pice of classical alarmism (on the surface). This is an interesting disinformation strategy, since it serves to perpetuate the myth that GW discussion is 'commy' alarmism. If you want to be truly horrified by our ability to learn nothing and care less, skip the article, which is drivel, and go to the comments. The message is not getting through! 

Global Warming Caused by Jupiter - thank heavens! (semi-empirically)

When I noticed a comment and link from Nicola Scafetta on Judith Curry's blog, my curiosity was piqued. Back in the day, Scafetta, Moon et al. were lauded as champions of the climate change doubters community and by and large critiqued negatively by most if not all of the climate scientists who blogged back then.

At the time, I'm fairly sure the furore was about attribution to Solar influences and, having kind of assumed that this had been looked at a lot recently and largely worked out, I thought I'd have a closer look.

The link kindly provided by Dr S. on JC's blog goes to a paywall, but the actual paper is available on his own page, here (for the time being). If the link goes down, no worry, I've saved a pdf just in case.

So what's it all about, NS? Snappily entitled Discussion on climate oscillations: CMIP5 general circulation models versus a semi-empirical harmonic model based on astronomical cycles, the paper compares a semi-empirical model produced by NS with the CMIP5 models and finds the latter wanting. Quoting:

     Power spectra of global surface temperature (GST) records (available since 1850)      reveal major periodicities at about 9.1, 10–11, 19–22 and 59–62 years. Equivalent  oscillations are found in numerous multisecular paleoclimatic records. The Coupled  Model Intercomparison Project 5 (CMIP5) general circulation models (GCMs), to be used  in the IPCC Fifth Assessment Report (AR5, 2013), are analyzed and found not able to  reconstruct this variability. In particular, from 2000 to 2013.5 a GST plateau is observed  while the GCMs predicted a warming rate of about 2 °C/century. In contrast, the  hypothesis that the climate is regulated by specific natural oscillations more  accurately fits the GST records at multiple time scales.

As usual, the reading is my non-scientist's rough watering down. In summary, about half of the GW observed since 1850 'could' be attributed to 'natural oscillations'. These oscillations are linked to half a dozen interplanetary relations - Sun/Moon, Sun/Jupiter, Jupiter/Saturn, etc.

Now this hypothesis, that our temperature is affected significantly by such distant forces as those from Jupiter and Saturn, is not an new revelation from Scafetta, so perhaps I'm behind the curve on this one again, but to my (untrained) eye, this hypothesis seems at the least counter-intuitive. It puts me in mind (no doubt unfairly) of Astrology.

I've no doubt that a suitably qualified analyst can explain very simply whether this is a legitimate line of enquiry or not - I'll try not to let my prejudices get in the way - but since I'm fairly sure someone will trot this out as 'proof' or 'evidence' that AGW is not all it's cracked up to be, it would be useful to get clarity on what is wrong with this hypothesis. As usual, depending on responses...

On the rocks, no ice

A swift trawl through some of the Open Access Journals has brought up this gem from The Cryosphere:

Global glacier changes: a revised assessment of committed mass losses and sampling uncertainties

S. H. Mernild^1,2, W. H. Lipscomb³, D. B. Bahr^4,5, V. Radić⁶, and M. Zemp⁷

Abstract. Most glaciers and ice caps (GIC) are out of balance with the current climate. To return to equilibrium, GIC must thin and retreat, losing additional mass and raising sea level. Because glacier observations are sparse and geographically biased, there is an undersampling problem common to all global assessments. Here, we further develop an assessment approach based on accumulation-area ratios (AAR) to estimate committed mass losses and analyze the undersampling problem. We compiled all available AAR observations for 144 GIC from 1971 to 2010, and found that most glaciers and ice caps are farther from balance than previously believed. Accounting for regional and global undersampling errors, our model suggests that GIC are committed to additional losses of 32 ± 12% of their area and 38 ± 16% of their volume if the future climate resembles the climate of the past decade. These losses imply global mean sea-level rise of 163 ± 69 mm, assuming total glacier volume of 430 mm sea-level equivalent. To reduce the large uncertainties in these projections, more long-term glacier measurements are needed in poorly sampled regions.

In layman's terms, the authors are suggesting that (accepting high uncertainty) the World's glaciers and ice caps are shrinking faster more out of balance than previously estimated, with a consequential increase in their contribution to global sea level rise. This conclusion is premised on a future climate resembling that of the last ten years (so no projection included for increasing mean annual temperatures).

I'd be interested to get Stoat's response - it's his kind of thing, as well as those of similar inclination. My first thoughts are that here is more suggestive evidence that the synthesis estimates of future change represented by the AR5 tend to underestimate likely future climate-related trends. 

The niggling worry is that there may be a cumulative imbalance - for each metric a conservative estimate, each conclusion/estimate slightly understated - and, if it proves otherwise, the gross cumulative change is far more substantial than the projections. In this case, the paper draws our attention to something I have previously researched and have an interest in - global seal level rise. There are plenty of voices in the scientific community already saying that the AR5 estimates are conservative - here is another potential string to their bow. At it, friends...

(Indeed, Stoat responds here: http://scienceblogs.com/stoat/2013/09/30/ar5-cursory-review-of-chapter-4-cryosphere-mass-balance-of-antarctica/ see comments 8&9.) Thanks, William.

Further comment: since it is a well established and credible blog, the discussion continues at WC's site - no point in duplicating effort. Please go there and read on...