BlueSkiesResearch.org.uk: Is the concept of ‘tipping point’ helpful for describing and communicating possible climate futures?

There’s a new book just out "Contemporary Climate Change Debates: A Student Primer" edited by Mike Hulme. I contributed a short essay arguing the negative side of the above question. It was originally intended to be "Will exceeding 2C of warming lock the world onto a 'Hothouse Earth' trajectory?" but no-one could be found to argue in favour of that (this was shortly after the publication of the Steffen nonsense) so we settled on something a bit more vague. Maybe I should summarise my compelling argument but don’t have time right now so you’ll have to take my word for it.

I haven’t had time to read the book but my complementary copy just arrived (hence the post) and the table of contents is quite interesting, so maybe it would make a good Christmas present for the person who is interested in climate change – or even for someone who isn’t!

Introduction: Why and how to debate climate change
Mike Hulme
1. Is climate change the most important challenge of our times?
Sarah Cornell and Aarti Gupta
PART I: What do we need to know?
2. Is the concept of 'tipping point' helpful for describing and communicating possible climate futures?
Michel Crucifix and James Annan
3. Should individual extreme weather events be attributed to human agency?
Friederike E.L. Otto and Greg Lusk
4. Does climate change drive violence, conflict and human migration?
David D. Zhang and Qing Pei; Christiane Fröhlich and Tobias Ide
5. Can the social cost of carbon be calculated?
Reyer Gerlagh and Roweno Heijmans; Kozo Torasan Mayumi
PART II: What should we do?
6. Are carbon markets the best way to address climate change?
Misato Sato and Timothy Laing; Mike Hulme
7. Should future investments in energy technology be limited exclusively to renewables?
Jennie C. Stephens and Gregory Nemet
8. Is it necessary to research solar climate engineering as a possible backstop technology?
Jane C.S. Long and Rose Cairns
PART III: On what grounds should we base our actions?
9. Is emphasising consensus in climate science helpful for policymaking?
John Cook and Warren Pearce
10. Do rich people rather than rich countries bear the greatest responsibility for climate change?
Paul G. Harris and Kenneth Shockley
11. Is climate change a human rights violation?
Catriona McKinnon and Marie-Catherine Petersmann
PART IV: Who should be the agents of change?
12. Does successful emissions reduction lie in the hands of non-state rather than state actors?
Liliana B. Andronova and Kim Coetzee
13. Is legal adjudication essential for enforcing ambitious climate change policies?
Eloise Scotford; Marjan Peeters and Ellen Vos
14. Does the 'Chinese model' of environmental governance demonstrate to the world how to govern the climate?
Tianbao Qin and Meng Zhang; Lei Liu and Pu Wang
15. Are social media making constructive climate policymaking harder?
Mike S. Schäfer and Peter North

BlueSkiesResearch.org.uk: Steffen nonsense

Been pondering whether it was worth bother blogging this but I haven’t written for a while and in the end I decided the title was too good a pun to pass on (I never claimed to have high standards).

The paper "Trajectories of the Earth System in the Anthropocene" had entirely passed me by when it came out, though it did seem to attract a bit of press coverage eg with the BBC saying

Researchers believe we could soon cross a threshold leading to boiling hot temperatures and towering seas in the centuries to come.
Even if countries succeed in meeting their CO2 targets, we could still lurch on to this “irreversible pathway”.
Their study shows it could happen if global temperatures rise by 2C.
An international team of climate researchers, writing in the journal, Proceedings of the National Academy of Sciences, says the warming expected in the next few decades could turn some of the Earth’s natural forces – that currently protect us – into our enemies.

and continues in a similar vein quoting an author

“What we are saying is that when we reach 2 degrees of warming, we may be at a point where we hand over the control mechanism to Planet Earth herself,” co-author Prof Johan Rockström, from the Stockholm Resilience Centre, told BBC News.
“We are the ones in control right now, but once we go past 2 degrees, we see that the Earth system tips over from being a friend to a foe. We totally hand over our fate to an Earth system that starts rolling out of equilibrium.”

Like I said, I had missed this, and it was only an odd set of circumstances that led me to read it, about which more below. But first, the paper itself. The illustrious set of authors postulate that once the global temperatures reach about 2C above pre-industrial, a set of positive feedbacks will kick in such that the temperature will continue to rise to about 5C above pre-industrial, even without any further emissions and direct human-induced warming. Ie, once we are going past +2C, we won’t be able to stabilise at any intermediate temperature below +5C.

The paper itself is open access at PNAS. The abstract is slightly more circumspect, claiming only that they "explore the risk":

We explore the risk that self-reinforcing feedbacks could push the Earth System toward a planetary threshold that, if crossed, could prevent stabilization of the climate at intermediate temperature rises and cause continued warming on a "Hothouse Earth" pathway even as human emissions are reduced. Crossing the threshold would lead to a much higher global average temperature than any interglacial in the past 1.2 million years and to sea levels significantly higher than at any time in the Holocene.

(the paper fleshes out these words in numerical terms).

The paper lists a number of possible positive carbon cycle feedbacks and quantifies them as summing to a little under half a degree of additional warming (Table 1 in the paper). The authors then wave their hands, say it could all get much worse, and with one bound Jack was free. End of paper. I went through it again to see what I’d missed, and I really hadn’t. It is just make-believe, they don’t "explore the risk" at all, they just assert it is significant. There’s a couple of nice schematic graphics about tipping points too.

The mildly interesting part is what led me to read the paper at all, 6 months after missing its original publication. An editor contacted me a little while ago to ask if I’d write half a of debate (to form a book chapter) over whether exceeding 2C of warming would lock us onto a trajectory for a much warmer hothouse earth. I was charged with arguing the sceptical side of that claim. I was initially a bit baffled by the proposal as I had not (at that point) thought anyone had claimed anything to the contrary, but it soon became clear what it was all about. I said I’d be happy to oblige, but it turns out that my intended opponents, being two of the co-authors on the paper itself, were not prepared to defend it in those terms.

That IPCC thing

Hello faithful blog readers. After a long absence I'm going to try to post some things again. Got a small backlog of ideas to write about and a little bit of free time to work at them.

I'll start with the tedious 1.5C nonsense since I can sense that you are all (both?) desperate for my opinions. The simple and efficient way for the IPCC to have responded to the stupid proposal from politicians that, having made no progress towards limiting global warming to 2C, they would instead really really try really really hard to limit it to 1.5C honest guv we really really mean it this time, would have been to say "No you won't, you are just pretending. Now go away and do something constructive rather than delaying and passing the buck". That would have saved a lot of money and CO2 emissions. But instead, we get lots of meetings, papers, scientists pontificating on the radio and ridiculous misrepresentations(*) like the Grauniad saying we have 12 years to save the planet. Back in 2008 we had less than a decade, so that's a step in the right direction.

What. A. Waste. Of. Time. And. Effort.

Perhaps Douglas Adams put it best when he said

I love deadlines. I love the whooshing noise they make as they go by."

(*) misrepresentation of the reality. I really don't much care whether it's the IPCC's fault for inviting this sort of interpretation, or the Grauniad for being clueless, or someone in the middle causing confusion. It's a gift to denialists either way.

Is the Food Standards Agency fit for purpose?

Fans of Betteridge's Law will already know the answer....

This is about the latest food scare of course. Toast and “overcooked potatoes” which was later revealed to refer to roasted potatoes (and well-fried chips) are the supposed culprits this time. It's not the first time we've been warned about acrylamides, and probably won't be the last. It's all nonsense, sadly. The basic problem with the FSA approach is that it identifies and publicises chemicals as being likely to be a cancer causing agent, without any(*) consideration of the dose required. As David Spiegelhalter's excellent article explains, a typical human diet contains around 100th of the dose that has been observed to lead to a modest increase in the rate of tumours in animals. And despite all the studies that have been done, no-one has found any link between acrylamide and tumours in humans. But that doesn't stop the FSA generating scare stories about how we shouldn't toast bread properly, or roast our potatoes (I heard someone recommend 45 mins in a cool oven which would just produce soft greasy pallid lumps).

Incidentally, that article probably doesn't blow DS's horn sufficiently for people to realise how authoritative an expert he is. He is Winton Professor for the Public Understanding of Risk in the Statistical Laboratory, Centre for Mathematical Sciences, University of Cambridge. When he writes about something, he's probably right.

Anyway, I'm going to keep on roasting.

* not strictly true as a careful reading of David Spiegelhalter's article reveals. But the margin of safety has to be astronomical, rather than merely huge, in order for them to discount it.

Apocalypse now?

Lots of people have asked about this paper (which I think is open access).

To cut a long story short, it's not silly - the authors are entirely respectable and the work is interesting - but I don't think it is really that credible in terms of overturning established consensus. In fact it looks to me like they've gone astray in a few ways which add up to provide plenty of reasons for doubting the result.

The underlying idea is interesting enough and I have no problem with it in principle. They looked at climate change over multiple glacial cycles, to estimate not only the climate sensitivity, but also tease out how much this varies with temperature. Their observed temperature record comes from a handful of long-term proxy records of sea surface temperature, just 14 in total, which do not give very good global coverage. So they start by calibrating these records to a global mean temperature by comparing the local (proxy location) to global temperature at the last glacial maximum as simulated by models. The LGM temperature change arising from their 14 proxy records scaled to global temperature is about 5C colder than pre-industrial. This is a fair bit colder than the 4C we got with 400 data points over both ocean and land. But not content with this, they then average it with the mean of the PMIP model simulations, which is 6.5C colder than PI, thus getting a cooling of almost 6C.

Edit: Thanks to an email from Axel, I've had a more careful read and the above is wrong. One estimate is the PMIP models scaled to match data ("proxy-based"), another is their LOVECLIM simulation scaled to match a different data set ("model-based").
 
It is probably defensible to use the PMIP models in this way as some sort of independent estimate of the LGM state, but surely it is inconsistent to not then also use the PMIP models to estimate the cimate sensitivity and/or its nonlinearity. Anyway, this cold LGM state feeds through into a high sensitivity. An important additional factor here is the nonlinearity which they diagnose by comparing temperature to net forcing throughout the time series. I think a fair bit of this nonlinearity relates to the very high interglacials which are at best poorly calibrated since they only calibrated the proxy records to a fully glacial state. Interglacials have much smaller global temperature signal compared to the present, with the regional differences being much more important, and it seems doubtful whether a single scaling applied to these 14 proxy records could represent the true relationship with adequate precision for their purposes.  In support of this, the last interglacial appears to have extremely high warmth in their calibrated proxy record of some 3C above pre-industrial, which I don't think is widely accepted. On the other hand, some nonlinearity is probably quite plausible, so let's press on. Using the "warm" sensitivity of 4.9C/doubling, they then generate a transient prediction, using a simple energy balance with the ocean heat uptake factor again taken directly from the CMIP models.

Disappointingly, their plot of the transient warming from 1880-2100 doesn't show the actual observations up to the present. It is hard to be precise from eyeballing a computer screen, but it looks to me that their new improved prediction is already way ahead of observations. It suggests a warming that first reaches 1C (relative to 1880) back in the early 1990s before Pinatubo, rebounding from that brief dip to reach about 1.5C by the present. HadCRUT4 shows rather less warming that this, with even the current extraordinary hot year (boosted by a strong El Nino) not reaching 1.2C on that anomaly scale. In my view failing to show, or discuss, this discrepancy is a major failing of the paper. If they think it can be explained by internal variability then they should have presented that discussion and I'm surprised the reviewers let them get away without it.

Edit: ok, here is a very quick and dirty attempt to show what their pic would have looked like with real temperatures on it:

Not a great graphic, I just scaled the hadcrut pic off here and tried to line it up with the authors' own axes, matching the baseline temps around the end of the 19th century.  As anticipated, recent years are well below their prediction, with 2016 just about reaching the CMIP mean.

Edit: Axel claims that internal variability can explain this discrepancy, but I don't believe it. The magnitude of decadal-scale internal variability is about 0.1C (Watanabe et al 2014 and Dai et al 2015) and this new forecast would be even hotter if it wasn't also hugely overestimating the response to volcanoes.

So, in summary, nice try, but I don't believe it, and I don't really think the authors do either.

[Blog post title inspired by the Mark Lynas quote which is not the authors' fault. Incidentally, it is disappointing to see journalists falling for the parasitic publishing scam in which "one of the most respected academic journals" cashes in on its name by setting up numerous sister journals which share some elements of the name but neither the editorial policy nor barriers to entry. "Science advances" is not Science and it's only been around for a year or so, nowhere near long enough to have any sort of reputation. But if journalists don't know the difference, scientists will happily pay the steep publication charge and reap the publicity benefits. Nature have been doing this for a few years now (eg Nature Communications) so it's hardly surprising Science have followed suit.]

Wickedly simple

I wasn't planning on writing anything about the Grundmann letter in Nature (paywalled of course, but you aren't missing much) as it seemed to be a pretty trivial “what about meeeeee” whine. ATTP put it best:

“In my opinion, one way to ensure that more is recognised would be to write stuff worth recognising, rather than simply insisting that people do so.”

Both there and at the Onion, I haven't seen anything much to revise my previous jaundiced opinion as to the value of social science. I hope to be proved wrong but won't be holding my breath in the meantime.

One thing that I did find useful in the letter was a clear definition of what he thought it meant for a problem to be wicked: “Most importantly, wicked problems do not have a stopping rule. [...] Climate change does not have a stopping rule.”

I think that's pretty much flat out wrong. I know that people like to add on their favourite hobby horses of climate variability and social vulnerability etc, and some of the wording is vague, but the basic problem that has motivated and dominated the research agenda for many years is due to us pumping out millions of tonnes of fossil-fuel-derived CO2 into the atmosphere. Cut net emissions to about zero and the problem is solved. Sure, if you choose to define “climate change” sufficiently broadly, then you can always find something else to worry about, but stopping the global-scale experiment that we are currently performing would suffice for practical purposes. As they say, “good enough for govt work”.

For my next trick, I'll consider the problem of model independence.

"untrue" that excessive calories caused obesity

So according to the National Obesity Forum (as reported by the BBC), it is

"untrue" that excessive calories caused obesity.

There's usually a gram of truth underlying each new bit of dietary advice that pops up in the news every 5 minutes. But it's generally buried under a mountain of hyperbole. It now seems clear that the anti-fat advice that I grew up with was somewhat exaggerated. However, does the NOF really expect us to believe that this fine fellow:

built up his fine physique through a strenous regime of cold showers and beatings alone? Incidentally, he's not one of the really fat ones, but he won the one tournament that we went to.

Nothing about this on the NOF website, which seems a bit odd.

Spot the difference

This Greek thing seems to be all the rage on some blogs I could mention, but I struggle to get excited by it. According to the Grauniad website today, The IMF views a debt-to-GDP ratio above 120% as unsustainable. Here, for some context, are some recent data for a couple of countries:

I won't be offering prizes for guessing the identities of Countries A and B. One of them has a collapsing population (1 million down in the past 5y, will be dropping at a rate of 1m per year by 2030), a flatlining economy, and a skyrocketing worker-to-dependent ratio that will exceed unity by the middle of the century (and keep on getting worse). The other is Greece.

The importance of priors!

I was amused to see the different publicity, and reaction, to two pieces of research recently. The first was that silly article about running, which claimed that too much running is bad for you. Interestingly, that BBC page seems to have changed from the tautologous "too much" to the term "running hard", which if anything makes it worse, becaue too much being bad is just a definition of what too much means, whereas running hard...well that's where the research falls down. It only took a couple of mins to find the relevant paper, which shows...huge error bars on estimated risk for hard runners, such that the confidence interval on the hazard ratio actually goes below 1 (at which point running hard is good for you!). The underlying problem is that study was small, there were only 36(?) runners in this group, and this simply isn't enough to show conclusively what the health effects would be. I believe that More or Less has dealt with this, though I haven't listened to it yet.

Then just yesterday, David Spiegelhalter drew my attention to a study on the effects of alcohol, which claimed that modest drinking had no benefits (in opposition to the widely held view that it did). He explains that the study was again underpowered, such that any modest effect would by construction not be "statistically significant". The underlying problem is that, as Andrew Gelman often mentions, where an effect is probably small (but non-zero) and only weak studies with small samples are used, any "significant" result will necessarily be a huge overestimate of the effect (ie, if the true value is x but the error bar is ±10x then only estimates that come out to as much larger than x, and perhaps even with the wrong sign, can be reported as significant), and any realistic estimate close to the true value of x will be found "insignificant" and therefore be liable to being discarded or denied by silly scientists.

One obvious solution is to use a Bayesian approach with a reasonable prior, which in both cases would have found that the new data were insufficient to overturn what was previously believed to be the case...but that won't publish high profile papers or sell newspapers.

Shock as Indescribablyoverhyped overhypes something

You can fool some of the people all of the time, and that's obviously the readership they are chasing:

Shock as retreat of Arctic sea ice releases deadly greenhouse gas

Portrayed as some new shock result presented at the AGU, it seems to have been a relatively mundane poster. It's only an Indie "exclusive" because no-one else was prepared to touch it with a bargepole. After a few years of stagnation, the methane concentration has been climbing again (oddly, the Wikipedia page is several years out of date). But it's a long way off being a threat anywhere close to the scale of, say, CO2.

Yes, I know I'm late on this - when I first saw it, I tried to check the AGU site to see what had been presented, but it was down.

Meanwhile, the Indie is on to the next looming catastrophe - and in these days of on-line access, it doesn't even serve as a decent chip wrapper.

Jaw-droppingly bad media coverage

Fox news had this wonderful graphic last week showing the location of Japanese nuclear power plants:



That "Shibuyaeggman" plant looks rather close to the centre of Tokyo. Let's zoom in a bit:


There it is, just north of Shibuya station. Seems a bit strange to put a nuclear power station in such a densely populated area, where you might be more likely to find a live music club instead. Oh, actually, it is a live music club. They even have a disclaimer up on their website stating that they have no nuclear power plant and are powered by music instead. Maybe they had Blondie headlining recently?

But we expect that from Faux News. Surely CNN can do better?



Not really, no.

Charlie Booker has some more:

Don't panic!

And I really really mean it this time...

Obviously I don't mean to belittle or diminish the huge devastation and suffering in northern coastal areas, where the news is pretty horrific. But down here in the Tokyo area, come on...the media hype is just ridiculous.

I would certainly say it's not a great time for a holiday here, but even Saturday's somewhat ad-hoc train journey home would have counted for a good day on the London Tube. Info on the planned rolling blackouts is a bit sketchy, but it seems that the first one (which was supposed to start here at 6:20am) has been postponed. It's inconvenient for our visitors trying to schedule meetings and seminars, but it is not threatening in any way. It's actually a great time of year for power cuts, our electricity consumption plummets in the spring anyway as the climate is so comfortable.

I did take a picture of the "empty shelves" in Tsukuba UPDATE now featured on the BBC. (Technically that is Niel's pic not mine, but it's the same shelf.) But I we had to frame it carefully to cut out all the full shelves round the rest of the shop. I'm not sure that my first thought in a disaster would be Hokkaido cheese cake and raisin bread though. Perhaps it is the chocolate croissant shortage that has panicked the cheese-eating surrender-monkeys into running away?




This is what panic buying looks like in Kamakura. Yes, we stockpile Perrier for emergencies. But only for washing with, we drink champagne :-)



Come on people, get a grip. It's an inconvenience. It is not, by any stretch of the imagination, a catastrophe down here, and the best thing most people can do is to get back to normality as quickly as possible. Turn off the wall-to-wall disaster porn on TV and have a look out of the window. It's a beautiful spring day and the cherries are starting to blossom.

Cycling kills!

A great bit of headline-writing from the Daily Wail:

Why cycling to work is one of the biggest causes of heart attacks

Yes, it's true, the roads round here are littered with the corpses of cyclists who have keeled over on the morning commute.

Or perhaps not. It might just be a piece of nonsensically over-hyped drivel - I report, you decide. A more rational discussion of the underlying research can be found here.

Firefox users can solve the "Daily Mail causes cancer" problem here. For those readers who aren't familiar with this particular rag, lucky you.

How to hype

A lovely bit of hype in the Torygraph caught my eye:

'Second sun' on its way

The Earth could find itself with a 'second sun' for a period of weeks later this year when one of the night sky's most luminous stars explodes, scientists have claimed.

So this remarkable event is "on it way" and "could" happen, "later this year". That's just the headline and subhead though. On reading the rest of the story, it might not happen for a million years. I'll not hold my breath then.

Monbiot exonerated

The long-anticipated Monbiot Inquiry has reported and finds that, while Monbiot's allegations were utterly baseless and incorrect, they were fully justified by the general atmosphere of fervid speculation that he built up surrounded him. No apology is necessary.

You may be surprised that Monbiot is not only the subject, but also the author, of this report. That's the way the press works these days. Self-regulation, donchaknow.

We now return to our regularly-scheduled manufactured scandal.

Muir Russell savages CRU!

Oh, no, actually he didn't.

BBC News - CRU climate scientists 'did not withold data'

It's the end of the world as we know it!

Or maybe not.

Hot on the heels of the latest exoneration (and in anticipation of the next - possibly the last?), Fred Pearce has rounded up a handful of the usual suspects to claim that the stolen emails have been a "game changer".

I suppose as it becomes increasingly clear that there really was nothing to get excited about we can look forward to increasingly desperate attempts to puff up this irrelevant sideshow into something worthwhile. After all, a lot of journalists (and some scientists too) staked a fair bit of their credibility on this actually amounting to a hill of beans.

Talking of my pal Fred Pearce, he couldn't resist trying to push a "climategate" frame on the McLean et al stuff just recently. Of course there is absolutely no link other than that a couple of our wholly innocuous emails were revealed amongst the hacked documents. Other than that, the article is just some rather empty he-said-she-said and it seems Pearce didn't even bother to confirm that the MFC's reply really was rejected by JGR, merely reporting this as an allegation. [He did email me with some questions just before writing that article, but nothing related to what he actually wrote.]

Barbecue summer - the sequel!

Oh, I suppose I shouldn't poke fun. Having got their fingers burnt last year - or perhaps I should say, having had their parade thoroughly rained on - the UK Met Office is declining to offer public forecasts, but is still doing "experimental" research on seasonal prediction and has obviously given a nod and a wink to the author of this Times article.

Of course we all know how the last "barbecue summer" turned out:

“Well, let’s put it this way. I’ve put my barbecue in the shed,” Dave says. “I don’t want it to get any rustier.”

I'm going to be in the UK for a chunk of the summer, so I hope they have got it right this time.

I am reminded that earlier this year, the BBC put out its weather contract to tender. Rumour has it that the esteemed Piers Corbyn, in a change of focus from his current work in volcano and earthquake prediction (no I'm not joking on that bit), is putting in a strong bid.

Phil Jones exonerated part 2

I've been remiss in my blogging duties due to a lengthy invasion of Annans, which was due to be over today, though one straggler is still awaiting the reopening of European air space...

Anyway, here's an straightforward opener to ease myself back into the swing of things.

Phil Jones has been exonerated again, this time by Lord Oxburgh's enquiry:

The inquiry, the second of three set up in the wake of the controversy, found "absolutely no evidence of any impropriety whatsoever", according to Lord Oxburgh, who led the investigation.

That follows hard on the heels of the previous exoneration. I suppose this must prove the great climate science conspiracy is still growing! But though I am sure there are some ongoing sighs of relief that the charade is at least coming to a sane conclusion, there actually isn't anything of interest that the climate science community hasn't been saying for months if not years. See mt, Stoat and RC for more on the story. Or perhaps I should say, more on the nothing that has been turned into a story.

One minor point to highlight is that I was pleased to see Lord O explicitly draw attention to the part the Govt has played in the "culture of secrecy" though restrictive IP agreements and policies. I don't think this is necessarily a free pass for scientists, who have sometimes been a bit too possessive for my liking, but it is certainly a factor which should be recognised and taken into consideration (unlike the previous HoC investigation which didn't seem to be aware of it, or perhaps preferred to gloss over their contribution to it).

OMG we're all going to drown!!!111!!11

A shame to see supposedly reputable sites like the BBC credulously swallowing this nonsense:

"Global warming claims a tiny island disputed by India and Bangladesh in the Bay of Bengal, scientists say."

(that line is actually the lead from the front page, it doesn't appear in the story, but the sense of it does)

The "island" in question is a sandbank in a river delta that only appeared in 1970 following a storm: it reached 2m above sea level at its zenith but has now pretty much vanished. Clearly, sea level has not risen anything like 2m in the last 40 years, so the whole story is complete nonsense from start to finish. Anyone who has lived near a shallow sandy coast or river delta will have seen how the topography shifts gradually or even rapidly, due primarily to storms and waves shifting around the sediments. The main scientist quoted appears to be a nobody making up stuff for the sake of some headlines.

Of course we've been here before with this nonsense Lean article from a few years ago. Oh, I see it's the same scientist behind that too. Ho hum.