Monthly Archives: September 2014

Tamsin’s Topsy-Turvy TED Talk

Energetic young climate scientist Tamsin Edwards, currently in the process of relocating from Bristol to the Open University, gave a TED Talk on How to love uncertainty in climate science a couple of days ago. At the time of writing there are no comments under her blog post, which is probably because she is too busy to moderate them.

There are a lot of good things in the talk.

  • Addressing the issue of uncertainty as the main topic, and acknowledging that uncertainty levels in climate science are far higher than in other areas such as experimental physics.
  • The explanation of climate models, acknowledging that they are simplifications, with the “All models are wrong” quote, and the statement that “their predictions partly depend on the numbers you plug in” and “we can’t always know what those numbers should be”.
  • Discussing the journalistic spin problem – how the same piece of research on sea level rise was reported as both “worse than feared” and “less severe than feared”.
  • It’s a well-written, clear and structured piece.

But unfortunately there are a couple of things that are completely wrong, in fact backwards:

“Not everyone knows this, but more and more climate sceptics agree with us too”

This is a recent fairy story in the climate community. In fact studies repeatedly show that people are getting more sceptical about climate change, not less.

Climate sceptics are getting more confident that they are right (that the climate scare has been greatly exaggerated), as each climate prediction fails.

In fact it is the climate scientists who are coming round to agreeing with the sceptics. After years of denying that there was any slow-down or pause in warming, it is now one of their main topics of research. Similarly, after insisting that natural variation of the climate is small compared with man-made “forcing”, they are now acknowledging, as sceptics have been saying for years, that chaotic fluctuations and natural cycles are an important factor.  As Tamsin says in her talk, climate scientists have in the past not sufficiently discussed uncertainty, leading them to make over-confident claims. The IPCC, in its latest AR5 report, has climbed down from some of the claims about extreme events made by AR4.  The IPCC has slightly reduced its range of values for climate sensitivity, as more papers come out with lower estimates. And on the policy front, while the farcical climate talk circuit continues, more and more people are realising that global agreements on mitigation are not going to happen, and that the logical approach is to adapt to climate change if/when it happens.


“That pause in warming of the atmosphere surprised the media and public, even though scientists always expected this kind of thing could happen in the short term”

This claim was made in one of Tamsin’s earlier blog posts, pause for
thought, where it was much criticised.
Climate scientists did not expect the pause.

  • The IPCC AR4 in 2007 projected 0.2C per decade over the next couple of decades.
  • The Met Office in 2007 predicted 0.3C of warming from 2004-14.
  • Lean & Rind 2009 predicted strong warming in the next 5 years.
  • Trenberth said (in 2009) “where the heck is global warming”,
    “we can’t account for the lack of warming at the moment and it is a
    travesty that we can’t.”, while Schneider spoke of someone betting a
    lot of money on a prompt upward spike, and Jones said they’d be
    worried after a 15 year pause.
  • James Annan placed a bet on warming with sceptic David Whitehouse, and lost.

The statement is backwards – it was the climate scientists themselves who were most surprised by the pause.

Remember what Feynman said: “The first principle is that you must not fool yourself — and you are the easiest person to fool.”

The Snailgate Papers

The story of the snail Rhachistia aldabrae miraculously coming back to life after being declared an extinction victim of climate change has been getting a fair amount of attention, following a WUWT post, a Delingpole piece, and an article in the Times by Ben Webster (paywalled, but excerpts available via GWPF or Bjorn Lomborg). Now, inevitably, referred to as “Snailgate”, the incident looks bad for the Royal Society, who rejected a paper questioning the alleged extinction, and has still not taken any action (such as a note on the original incorrect paper, or retracting it) after proof of the snail’s resurrection.

An article in Forbes helpfully gives links to the papers concerned.

The original paper was Gerlach (2007) Short-term climate change and the extinction of the snail Rhachistia aldabrae, in a Royal Society journal called Biology Letters. That paper was submitted on June 18 and accepted July 11, an unusually fast turn-round. The methods used by Gerlach to claim extinction seem rather flimsy, based on examination of collections containing specimens.

The rebuttal paper, written by Clive Hambler and others, was rejected and does not seem to be available [Update 20th Oct: it is now, see comment below]. We know from the Webster article that it pointed out that most of the habitat was inaccessible and has never been visited, and correctly predicted rediscovery of the “extinct” snail. It appears that the Hambler script was sent to the same reviewers who had accepted the Gerlach paper, which Delingpole rightly describes as a conflict of interest.

Papers that have cited Gerlach (2007) can be found with Google Scholar, which says there are 12 – not many for such a prolific field. The most high-profile of these is Cahill et al (2013), How does climate change cause extinction?, published in Proc Roy Soc B, which itself already has 79 citations.
According to Webster’s article, Cahill et al “suggested that this was the clearest example of man-made climate change causing an extinction.” The wording used by Cahill et al is in fact a bit more oblique than Webster implies: “In almost all cases, the links between extinction and anthropogenic climate change are speculative (but see [82]), which is why these cases were not included previously in our review.” [82] is the Gerlach paper.

The Cahill et al paper was much cited by IPCC AR5 WG2, see Chapter 4 here (IPCC did not cite Gerlach). This chapter presents mixed messages – on the one hand we have “only 20 have been tenuously linked to recent climate change (Cahill et al., 2013)” but then there is the worrying suggestion that climate scientists just have to look harder for evidence to confirm their hypothesis: “This does not mean that climate has not played an important contributing role; indeed it has been argued that the low level of confidence in attribution is due to the lack of studies looking for climate signals in extinctions (Cahill et al. 2013).” There are some outright alarmist statements, such as this one quoted in the media: “These considerations lead to the assessment that future species extinctions are a high risk because the consequences of climate change are potentially severe, widespread and irreversible since extinctions constitute the permanent loss of unique life forms” (not linked to Cahill et al).

So what should happen now? Justin Gerlach should have the integrity to ask the Royal Society to withdraw his incorrect paper. He has written an article on his website acknowledging the rediscovery of the snail, but makes no mention of any retraction of his paper.

As long as he and the Royal Society take no action, snailgate will continue to provide fodder for the sceptics.