BN Training Workshops

We are pleased to announce that Bayesian Intelligence will again be running a series of Bayesian network training workshops in Melbourne this year.

There will be six days of workshops, with the introductory BN training running in both April and June:

  • April 4th: Introduction to BNs
  • April 5th: More on BNs
  • June 27th: Introduction to BNs
  • June 28th: More on BNs
  • Sep 26th: Programming BN solutions with Netica (the basics)
  • Sep 27th: Programming BN solutions with Netica (advanced topics)

People are invited to register for any combination of the training days that best suits their background in BNs and their interests.

For more information, schedules and registration, please visit, or contact Steven via email or on 0425 801 277.

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.