These are just some of the shortcomings of Bengtsson's recent guest post

Since the severe criticism of Lennart Bengtsson from some of us at Uppsalainitiativet in the last few weeks (post 1, post 2, post 3) had begun to attract some international interest (see, e.g., Eli Rabett's translation of post 1), we felt it would be a good service to the international community to publish an English translation of Bengtsson's response to us. We imagined that the many glaring shortcomings of his rambling arguments and the untenability of his position would be evident and speak for themselves, but judging from the number of enthusiastic supporters of Bengtsson's text that showed up in the comments section, it seems that some clarification is needed. We already stated, in the brief introduction to the translation, that "our translation and publication of this text in no way means that we endorse the views expressed in it". Stronger language than that is warranted, and let me state it bluntly: much of what Bengtsson writes in his blog post goes right against our blog's subtitle "TAR KLIMATVETENSKAPEN PÅ ALLVAR", which in English reads "TAKES CLIMATE SCIENCE SERIOUSLY".

Going to specifics, Dana Nuccitelli has already provided a list of five specific errors in Bengtsson's post. I will start from Nuccitelli's list, elaborate a tiny bit on some of its items, and then add a couple more points at the end.

1) Anthropogenic climate change has increased several types of extreme weather, particularly heat waves, and is projected to intensify many others, for example drought intensity. http://www.skepticalscience.com/extreme-weather-global-warming-intermediate.htm

Exactly so. Here's that link again. The fact (pointed out by an anonymous commentator further down) that the IPCC mentions ambiguities and the inconclusive state-of-the-art concerning specific kinds of extreme weather does not warrant misleading statements like Bengtsson's "Apart from a possible increase in precipitation and a possible intensification of tropical hurricanes that has not yet been detected, there are no indications of extreme weather in the model simulations, and even less so in current observations".

2) There seems to be some confusion about the ability to model the future perfectly vs. the ability to project a distribution of probable future climate changes. Prof. Bengtsson seems to argue that if we can't project future climate change perfectly then we can't project it at all (the chaos theory comments). In reality it's simple physics that if we continue to increase the greenhouse effect and global energy imbalance, that will cause hotter temperatures and 'load the dice' in favor of certain associated climate changes (stronger heat waves, droughts, intense precipitation, etc.).

Exactly. And let me add to this the ambiguity that Bengtsson plays with when he says that "climate cannot be predicted, and how future climate will turn out will not be known until future is upon us". Here he could mean either (a) the utterly trivial and uncontroversial fact (exemplified by IPCC:s broad "likely" range of 1.5 to 4.5°C for the value of climate sensitivity) that we cannot predict the exact future climate, or (b) the blatant falsehood that we cannot know anything about where the climate is heading, or (c) something in between these two extremes, in which case he needs to explain his position with a lot more precision than the empty rhetoric presented in his guest post.

3) Temperatures over the oceans are not representative of the warming of the planet as a whole.

Right. The kind of cherry picking that Bengtsson engages in with his statement that "the long period during the last 17 years with insignificant or no warming over the oceans" is unworthy of serious scientific discussion.

4) There is substantial research into the cause of the slight increase in Antarctic sea ice extent, which is happening in a region with warming temperatures.

Right. And I think Nuccitelli's blog Skeptical Science is worth refering to in this context.

5) If you still don't understand why your colleagues were upset that you joined GWPF, you need to spend more time looking into the comments and reports made by the group, for example about the IPCC and Michael Mann.

Yes. All it takes is a quick tour through the GWPF web site to see that they are an anti-scientific climate denialist organisation. The dismay expressed by Bengtsson's critics upon his joining the GWPF is amply justified, and analogous to what a well-known evolutionary biologist would surely hear from his colleagues in case he suddenly decided to join the Discovery Institute or some other creationist think tank.

That concludes Nuccitelli's list, but there is more. Let me just add two more items.

6) Bengtsson speculates on how "prominent Jewish scientists in the GWPF council [feel about] being labeled deniers". I am dismayed by his choice to bring ethnicity issues into this discussion, and I feel almost embarrassed to point out that "denier" and "Holocaust denier" are not synonymous concepts. Climate denialists like to conflate the two terms, usually in an attempt to change the subject of a conversation, and I am sad to see how Bengtsson chooses to resort to the same lousy trick.

Here I must add that I find it hypocritical, bordering on the bizarre, that Bengtsson falls back on a moralistic "Watch your mouth!" tactic, given his own far-reaching faiblesse for vulgar rhetoric, such as associating criticism against himself with "the time of McCarthy", and fantasizing about sending people not sharing his political opinions (such people in general as well as specifically yours truly) to North Korea.

7) Bengtsson resorts to Popperian falsificationism in branding findings to the extent that "even extremely cold weather, as this year’s winter in north Eastern USA and Canada, is regarded as a consequence of the greenhouse effect" as "pseudo-science". I refuse to lecture to Bengtsson about the many complexities and nonlinearities of the climate systems, leading to geographic inhomogeneity of global warming and various conuterintuitive phenomena; surely Bengtsson knows about these things (and probably a lot more than me, for that matter). The Wikipedia entry on last winter's cold spell in North America has a section on the possible role of anthropogenic climate change, containing plenty of references. The blank dismissal of such work as "pseudo-science" is just rude and anti-intellectual. Elsewhere, Bengtsson gives the same treatment to studies of melting in Antarctica (such as the recent one by Eric Rignot et al), recommending that they are not read but sent straight to the waste basket. Such dismissal of scientific work, based not on their methodology but on their uncomfortable results, is characteristic of climate denial, and it is just terrible to see how far in that direction Bengtsson has gone in recent years.

It is not uncommon, but always annoying, to hear people with apparently a very crude understanding of the theory of science point to Popperian falsificationism to label one study or another (or sometimes entire subjects) as "pseudo-science". A study does not become pseudo-scientific just because it fails to falsify some theory. If Bengtsson's invokement of Popper is to be taken seriously, then we would equally well have to rule out as "pseudo-science" the mid-1800's study of anomalies in the orbit of Uranus, because it led to the discovery of Neptune rather than the falsification of Newton's theory of gravity.