Weather and Climate Change: Faulty Logic

—Kevin B Korb

I have a lot of respect for Crikey, the online Australian newsletter. They report on a lot of things other media outlets won't touch, especially bias and disinformation in those other media outlets. But the other day, while reading a piece by Bernard Keane on the inconsistency of Tony Abbott's rejection of a carbon tax, after his having previously advocated one, I read:

Insistence that the planet is not getting warmer — or, as Abbott until recently insisted, is getting slightly cooler — has become more difficult to maintain publicly, despite the faulty logic of linking weather to climate. (B Keane, Crikey, 5 Feb.)

It is certainly the case that weather is not the same as climate. This is pretty clearly revealed by the fact that many global warming deniers are weather forecasters, whereas hardly any climatologists are deniers. (NB: there are a lot more forecasters than climatologists!) But denying a link between weather and climate is simply absurd. The relation between climate, the prevailing weather in a region and season, and the weather itself, on any given occasion, is stochastic: the climate system, plus specific, highly variable, conditions together determine the specific weather. That establishes a kind of probabilistic dependency —i.e., a link —which is widely recognized in society.

For example, only ignorant people or fools now deny that smoking causes lung cancer. This is so despite the fact that many smokers never get lung cancer. Some of them die too soon from other causes, such as emphysema. But many smoke contentedly for decades with no sign of the cancer showing up. Lawyers for tobacco companies used to point this out in trying to make the case that specific complainants had no basis for complaint, because their lung cancers might have been amongst those caused by pesticide exposure or smog or a stray cosmic ray striking a susceptible cell in the lung. But these defences have been abandoned, with even tobacco companies accepting some culpability for the disease in specific cases. The situation is analogous with weather and climate change. Was Katrina specifically due to global warming? Well, obviously not in its totality; but global warming heating the Gulf of Mexico likely contributed to its intensity. Specific events will never be entirely attributable to a broad-scale change, because the broad-scale change will never be entirely responsible for a specific event in all its specificity. Denying a linkage on that basis, however, is a nonsense. An accumulation of extreme weather events, and a statistical assessment showing that the probability of their extremity without global warming is rapidly vanishing, will eventually silence those who claim weather tells us nothing about climate.

Probabilistic dependencies are real. The link they establish, in fact, is just that between a stochastic hypothesis and the evidence which confirms it. Denying such a link is tantamount to denying the statistical foundations of empirical science.

If you want to "sound reasonable" by making some concession or other to global warming deniers, then you should do so by reporting something that is factual, rather than counterfactual. You can point out that many deniers have good dress sense, or sometimes use grammatical sentences, for example. Buying into their dogma about weather versus climate change can all too easily turn into buying into their rejection of science.

Science Slam

The Science Slam final will be held in few days in Cologne. The English-speaking world needs something like this as well! (see the list of countries at wikipedia.) What is the Science Slam?

I translate the corresponding page from

Was ist ein Science Slam?

The Science Slam offers students and researchers an opportunity to present their research projects in an entertaining 10-minute show on stage.

In contrast to a Poetry Slam any sort of aid is allowed: Power point, props or live experiments are welcome. When the Science Slam ends, the audience decides which Slammer goes home the winner.

The aim of Science Slam is to encourage scientists to present their work in a clear and easily understandable way. At the same time, the entertaining lectures for non-specialist audiences give people the chance to get infected by the enthusiasm of the slammers for their projects. Although research is the focus here, the scientific value of the lecture plays a subordinate role. Rather, the emphasis is on communication, and on showing the public what young scientists are devoting their energies to.


Bad Science

− Kevin B Korb

Bad science comes in a number of varieties, at least including the following:

  1. Sloppy science. This might include poor experimental design, poor measurements, slovenly reasoning, insufficient power in one's tests, failure to blind experimenters or subjects, etc. Presumably, the intentions are right, but the execution is wrong.
  2. Pseudo-science. This is fake science. The fakery may be intentional or unintentional. For example, cultists may intentionally generate some large-scale fantasy, while their followers unsuspectingly take it seriously. If the pseudo-scientific methods employed have the look and feel of science, then this is due to simulation or accident, and not due to the proper employment of scientific methods. For Karl Popper, demarcating real from pseudo-science was a kind of mission. He proposed a "falsificationist" criterion: that theories which were (or could be) protected from any possible contrary evidence were non-scientific. Unfortunately, this could never quite be made to work; there are no logical limits to what can be defended, or not, since, as Quine put it, all of our ideas are tied together in a "Web of Belief" (Quine and Ullian, 1978). Still, Popper was certainly on to something: those, such as climate change deniers, who spin excuses and rationalizations no matter what the evidence may be good propagandists, but they are not good scientists.
  3. Cheats. This is also fake science, but most likely not with a view to promoting a false story about the world, but instead a false story about the researcher.

Ben Goldacre's book Bad Science (Fourth Estate, 2009) treats miscreants and violators of scientific method primarily in the first two categories. Being a journalist (and MD) he, perhaps naturally, focuses largely on the aberrations and violations perpetrated by journalists. On his account, they've done quite a lot of damage. For example, around 2005 there were repeated scandals in the UK concerning rampant MRSA in UK hospitals, but the findings were all traceable to a single lab, "the lab that always gives positive results". Apparently, journalists responded to that description by anticipatory salivation, rather than anxious palpitation. It's a ludicrous, and sad, story.

For newcomers to scientific or medical research, Goldacre's book is an entertaining, accessible introduction to a host of issues you will need to know about: experimental design, bias in statistics, cheating by pharmaceutical companies in research and in advertising, the silliness of homeopathy, how we fool ourselves into believing what we want to believe and what measures can be taken to minimize our own foolishness.

For those well versed in these kinds of issues, the book, while a good source of anecdotes, is just a little disappointing. It's important to provide accessible accounts of science and method, but Goldacre goes just a bit far in dumbing things down, in my opinion. Popular science writers should not be assuming that their readers are idiots. He proposes as his motto: "Things are a little more complicated than that". Indeed, they are. Still, on the whole, this is a good and positive contribution to the public understanding of science.

(17 Nov 2012) I think perhaps I was a bit too negative at the end of the note above. Goldacre's book can be seen as an extended plea for a more evidence-oriented treatment of science journalism and, in particular, as a protest against the view that science is just too complicated for ordinary folk to understand — a view which he rightly condemns for promoting appeals to authority for arbitrating scientific disputes, rather than appeals to evidence. The result is a serious dumbing down of public policy debates, including a tendency to portray all sides of a scientific dispute as having equal support, because all sides can call upon any number of "experts". This message certainly needs to be spread. The quality of public debate about topics that concern science is very poor indeed.