Monthly Archives: February 2014

What does the IPCC say about flooding?

In view of the current wave of hysteria about flooding and the bogus claims from people who ought to know better, it’s timely to have a look at exactly what the IPCC has said about flooding.


In late 2011 / early 2012 the IPCC published a Special Report on Extreme Events, known as SREX for short.  This was a joint production of WG1 and WG2. Here is the statement on floods from the SREX SPM:

There is limited to medium evidence available to assess climate-driven observed changes in the magnitude and frequency of floods at regional scales because the available instrumental records of floods at gauge stations are limited in space and time, and because of confounding effects of changes in land use and engineering. Furthermore, there is low agreement in this evidence, and thus overall low confidence at the global scale regarding even the sign of these changes.

So they don’t even know whether flooding is increasing or decreasing – in which case it might have been more logical to say that there is not really any detectable change. On possible future change, they are similarly uncertain:

Projected precipitation and temperature changes imply possible changes in floods, although overall there is low confidence in projections of changes in fluvial floods.

AR5 2013

Turning now to the AR5 report, the first point to note is that the SPM does not include the word “flood” at all. There is an item in Table SPM1 on heavy precipitation events, which says there have been “likely more land areas with increases than decreases”, a less confident statement than in AR4 (“likely over most land areas”).

In the main text, flooding is discussed in chapter 2, section Here is what it says (references removed):

AR5 WGII assess floods in regional detail accounting for the fact that trends in floods are strongly influenced by changes in river management. While the most evident flood trends appear to be in northern high latitudes, where observed warming trends have been largest, in some regions no evidence of a trend in extreme flooding has been found, e.g., over Russia based on daily river discharge. Other studies for Europe and Asia show evidence for upward, downward or no trend in the magnitude and frequency of floods, so that there is currently no clear and widespread evidence for observed changes in flooding except for the earlier spring flow in snow-dominated regions.
In summary, there continues to be a lack of evidence and thus low confidence regarding the sign of trend in the magnitude and/or frequency of floods on a global scale.

Roger Pielke provided a useful summary of what the IPCC AR5 actually says about extreme events. His final are words were prophetic:  “Of course, I have no doubts that claims will still be made associating floods, drought, hurricanes and tornadoes with human-caused climate change – Zombie science – but I am declaring victory in this debate. Climate campaigners would do their movement a favor by getting themselves on the right side of the evidence.”

Rainfall data

Meanwhile, in a sequence of posts, Paul Homewood has been looking at the facts and plotting the Met Office’s own rainfall data (see for example here, here and here). It is quite clear from these graphs, and the graphs in Figure 3 of this Met Office document, that there is no trend in rainfall over the last 100 years.

Update 26 Feb:

The GWPF have produced a useful short video about the floods, the dubious claims of a climate link and the muddled statements by the Met Office on this. They also mention the IPCC SREX.

A flood of articles about adaptation

The blogosphere has been inundated with a deluge of posts about adaptation to climate change over the last week or so.   Newspapers also seem to be awash with a torrent …(OK, enough of that).

1.  Judith Curry reports on a joint US/UK meeting on adaptation held at her university, Georgia Tech, on “Robust Adaptation Decisions” and the science behind them. The first talk abstract says that adaptation is an increasingly significant policy response.

2. A social science paper about adaptation came out on Feb 14, Communicating adaptation to climate change: the art and science of public engagement when climate change comes home”. I can only get the abstract, not the full text, but it seems to be a review paper. It says “It reveals much”, but the abstract certainly doesn’t. 

3.  John Gummer, aka Lord Deben writes in the Guardian that “The government has to act now on climate change”, but beyond the cliche of the title, the article is all about preparing and adapting, calling for more spending on flood and sea defences, and ending by arguing for a re-organization of government responsibility.

4. At the Klimazwiebel blog, Reiner Grundmann has an article “Hijacking the floods”, commenting critically on a doom-mongering article by Lord Stern, and the Gummer article linked above, saying that politicians are using the floods for point-scoring rather than seriously addressing the adaptation issue.

5.  Leo Barasi says that this is what the next “fight” will be about (adaptation or mitigation). He still seems to think that we need to cut back our emissions to set an example, and still seems to suffer from the Communication Problem Delusion, saying that “people who want action on climate change need to find a new way of talking about it”.

6.  Andrew Lilico in the Telegraph says “We have failed to prevent global warming, so we must adapt to it”.  He argues that if one accepts that global warming is likely to be a serious problem, we should try to adapt to it rather than prevent it.  He first points out that this is an economic question, not a scientific one.  He discusses the failure of mitigation efforts over the last few decades, the pointlessness of the UK taking strong action in view of the rest of the world, the enormous costs and the unlikeliness of getting public agreement. He explains why adaptation is cheaper, more feasible and less risky.

7. Last and probably least, the chap formerly known as Wottsupwiththat  is talking about adaptation and mitigation. As usual he has very little understanding of the issues, but at least he is aware of this (“I don’t fully understand what’s going on”).

Of all these, the “must-read” is the one by Lilico. It is calm, rational, well-argued and beautifully written.

Dan Kahan on scientific communication

Dan Kahan from Yale University is currently visiting the UK and gave a talk at the University of Nottingham yesterday.  He’s well known for his work on risk perception and in particular the idea of “Cultural cognition”, on which he runs an active blog.  He has already posted up his overview of the talk, and the slides he used.

For those who have looked at his blog and his papers, the theme of the talk was quite familiar, but I found being present at the talk made things a lot clearer. He’s a very enthusiastic and energetic speaker, moving around the room, right up to the audience (he returns the compliment by describing Nottingham as “vibrant and bustling”).

He started with some remarks on the privilege of academic freedom, and then showed a graph of the strong left-right split on the assessment of climate change risk (which apparently gives much the same result for all climate-related questions).

He talked about the “public irrationality thesis”, the idea that the public tends to think quickly and emotionally, rather than slowly and logically as scientists do. If this was correct, then you’d expect public opinion to agree more with mainstream climate science opinion as science literacy and numeracy increased; but in fact this is not the case – there is a (very slight) negative correlation between climate change concern and science literacy (a result that was jumped on with delight by some climate sceptics).

His alternative hypothesis is “cultural cognition” – that there is a correlation with the individual’s way of thinking, in particular where they fit in a two-dimensional grid with hierarchist <-> egalitarian on one axis and individualist <-> communitarian on the other. In this diagram, people in the egalitarian, communitarian quadrant are more concerned about climate change, while those in the  hierarchist, individualistic corner are less concerned.

He was refreshingly non-partisan – emphasizing that it’s not a question of right and wrong or “pro-science” and “anti-science”, illustrating this with the case of nuclear power, which is the opposite way round in terms of agreement/disagreement with the mainstream scientific assessment. He also pointed out that most other issues don’t show such a divide, including water fluoridation and even GMOs.

There was a lot more in the talk – see his blog write-up – and it seemed he could have gone on for much longer if he hadn’t run out of time.

Of course it would be quite easy to question a lot of this. His results are from the US, and there is an impression that the partisan divide is less clear in the UK. What about people in the egalitarian individualist corner? Does it make sense to regard individualists as behaving as a group anyway? What about the various high-profile climate sceptics who have changed their minds, such as Anthony Watts and Patrick Moore?

Update 21 Feb:

A few days after his talk at Nottingham, Dan Kahan gave a similar but not identical talk at Cardiff. In his blog post on this talk, he includes an interesting figure that he didn’t show in the Nottingham talk:

This shows the cultural cognition effect: the HI group tend to be less concerned about climate change, while the CE group are more concerned. But it also shows that the CC effect is much stronger in the CE people than in the HIs: the green graph is more skewed to the right than the black graph is to the left. This relates to my question above – individualists are, more or less by definition, less inclined towards group-like behaviour than communitarians.

From another Kahan talk on the web, here’s a graph that shows the difference between the two groups even more clearly:

Mark Twain on the climate debate

The Shakespeare debate as an analogy for climate?

The so-called Shakespeare authorship question has some similarities to the climate debate. The vast majority (97%?) of academics working in the field have no doubt that the author of the plays was the actor from Stratford, though there are some exceptions. But many people, including prominent Shakespearean actors such as Mark Rylance, are doubtful.
Familiar tactics are employed by the two sides. The mainstream side has difficulty deciding whether to ignore the sceptics, or to criticise them at the risk of giving them publicity. When they do respond, they tend to characterise the doubters as nutters (one of them had the unfortunate name of Thomas Looney).  Some of the sceptics oblige by coming up with bonkers theories such as those presented in the film  Anonymous (in which some of Queen Elizabeth’s courtiers turn out to be her sons).  The mainstream refuses to accept that the sceptics have simply looked at the facts and found them unconvincing, but ascribes to them unusual personality traits or flaws that cause them to think this way.
The sceptics argue that the mainstream academics have a lot to lose, and are therefore biased. Sounds familiar?

Mark Twain’s book

One of the high-profile early Shakespeare sceptics was Mark Twain. In 1909, near the end of his life, he wrote a book called Is Shakespeare dead?, which expressed various doubts (such as the lack of any mention of plays or poems in Shakespeare’s will, and the dubious assumptions made by Shakespeare scholars based on virtually no evidence).

But as might be expected from Twain, some of the latter sections of the book satirise and ridicule the style of the debate. Again here there are some sections that seem distinctly familiar.

In Chapter 11 he gives a nice description of what is now called “confirmation bias” – the idea that once a viewpoint is established, evidence is no longer treated objectively, and discusses the pointlessness of trying to win the argument:

 “Am I trying to convince anybody that Shakespeare did not write Shakespeare’s Works? Ah, now, what do you take me for?…  I am aware that when even the brightest mind in our world has been trained up from childhood in a superstition of any kind, it will never be possible for that mind, in its maturity, to examine sincerely, dispassionately, and conscientiously any evidence or any circumstance which shall seem to cast a doubt upon the validity of that superstition.”

The most amusing bit is chapter 12, on the irreverence employed by the other side, who he refers to throughout as “thugs”.   Here are two excerpts:

“One of the most trying defects which I find in these Stratfordolaters, these Shakesperoids, these thugs, these bangalores, these troglodytes, these herumfrodites, these blatherskites, these buccaneers, these bandoleers, is their spirit of irreverence. It is detectable in every utterance of theirs when they are talking about us. I am thankful that in me there is nothing of that spirit.”

“It will surely be much better all around if the privilege of regulating the irreverent and keeping them in order shall eventually be withdrawn from all the sects but me. Then there will be no more quarrelling, no more bandying of disrespectful epithets, no more heart burnings.”

I was reminded of Twain’s remarks by some recent tweets from a well-known climate scientist complaining about childish name-calling:

Second evidence session for IPCC Review

Following the first oral evidence session two weeks ago, the Energy and Climate Change Committee is having a second evidence session today.

TV Broadcast here or here.

Unlike the first round, which was split half and half between upholders of the climate faith and dissenters, this session looks to be much more one-sided, and therefore probably not so interesting.

Panel 1, at 9.30am:

  • Sir Peter Williams, Royal Society
  • Dr. Emily Shuckburgh, Royal Meteorological Society

Panel 2, at 10.30am:

  • Guy Newey, Policy Exchange
  • Jonathan Grant, PricewaterhouseCoopers (PwC)
  • James Painter, Reuters Institute for the Study of Journalism, University of Oxford

The session explores a range of issues, including:

  • Attribution of the cause of climate change;
  • IPCC communication, media coverage and controversies;
  • Business and policy decisions in the face of uncertainty; and
  • National and international policy considerations.

The list of issues is intriguing, since it goes beyond the original remit of the review, which was mainly focused on the science and did not mention media communications (though policy was included).

The first two are scientists, though Emily Shuckburgh has also done some work on public opinion, co-authoring a report that found decreasing concern about climate change and decreasing trust.  They will presumably follow the line set out in the written submissions from their organisations. The RS one is very dull, churning out all the key words “unequivocal”, “robust”, “wealth of evidence”.  The RMetS submission is equally bland.

James Painter’s written submission referred to his document “Climate Change in the Media: Reporting Risk and Uncertainty”, about the interaction between uncertainty and policy.


Simon Carr at Guido Fawkes picks up on the Lilley/Shuckburgh and Lilley/Yeo spats.

BBC News also reports on this –  MPs Tim Yeo and Peter Lilley in climate committee clash.

BBC iplayer now has the recording of the session, though this only covers the first 2 hours.

The whole recording is here.