So for general relativity, it predicted a different rate of advance of the planet Mercury’s perihelion from that of the Newtonian theory. Eddington went to the Gambia for a solar eclipse and got a measurement for Mercury in accordance with the prediction of general relativity. And from that single experimenal result basis the theory of general relativity became established as one of the two building blocks of modern physics.

By comparison, the theory of global warming has been making many predictions – and getting many confirmations.

More than twenty years ago, the models were predicting for the north and west of Scotland a pattern that would be warmer, windier and wetter. That is exactly what we have got.

Now of course it may be that over a longer period some other factors may somehow cut in and the situation reverts to the staus quo. But the question is: is it worth taking that gamble? If a series of surveyors look at your house and tell you that its foundations are cracking because it’s built over old mine workings, do you ignore them on the basis that it’s just possible that they might be wrong?

In the case of climate change, if we act on it now, we not only cover ourselves against the climate predictions, we also tackle two other crises. One of these is the problem of declining supplies of oil, which mean that we have to get away from our dependence on it. And the second is the current global financial crisis, where we need to stimulate economic recovery by kickstarting new industries.

If the economies of the world had been investing more in new carbon-reduction R&D and less in financial services, we might all be better off in practical economic development terms now.

Let’s make up one. Car tires exploding on the highway are the number one cause of accidents. Sometimes people die when they explode. Therefore you should stop your car every 50 feet and check your tires so that you won’t die from exploding tires.

Now if we make his ridiculously over simplified chart, I can argue that you should at least stop your car every 20 ft and check because you could die, and if your wrong you will die.

Simply put it does not matter what you are arguing about the result is always the same, whether the reasoning is sane or not.

Your lottery example is a bit misleading because in a lottery all outcomes have the same likelihood. There are also usually far more combinations (speaking generally there are nine main combinations of climate change based on permutations of the three factors: a) it exists/does not exist, b) it is/is not caused by us (or we can do something to stop it, conversely) and c) we do/don’t do something about it. Of course these factors all vary by degrees but by modelling it like that you get a reasonably acceptable simplified model for possible futures)

However, of these permutations, it is an error to suggest that each has the same likelihood of occuring. Because we are in the system we are trying to study, we cannot say for certain what the exact probabilities of the outcomes are – but we can certainly look at evidence to see which is More Likely and weight our decision based upon this. This is simple decision making.

I wouldn’t play the lottery – 1 chance in 20000000 or whatever is not good odds. If this model resembled the pure chance statistics of a lottery, I’d agree with you. But we’re not talking about random chance here. The example is far more like predicting the path of a billiard ball – there are lots of factors but if you understand some of them you can make a pretty good estimate of how the ball will behave, at least for the first few bounces. If you collect more information on the probability of each factor, your understanding of which outcome is most likely helps you make the decision.

The IPCC reports suggesting 90% probability of some amount of climate change existing is such a collection of analysis of factors effecting climate change. Now, they don’t say for certain it’s happening – and they never will, for that is the nature of science, some factors will always give errors, or simply factors working in the other direction and a lower magnitude than the whole.

We can never say for certain that global warming doesn’t exist until a long way further down the line. But when the factors are studied, the chance of this outcome changes. At the moment that chance is greatly diminished by evidence, making the size of probability of the outcome ‘global warming doesn’t exist’ less.

In time science may change its mind and some evidence will skew the evidence the other way, making global warming less likely than its nonexistence. In that case I would be making the same argument, based on the probability, for inaction. However, currently we do not see this and the outcomes and their probabilities are skewed in such a direction that doing something makes sense.

That in essence is what this man is attempting to explain to the layman. Although his model starts out with four equal possibilities (essentially a lottery with 1 ball drawn from four numbers), he quickly goes on to say that we can weight these four (admittedly simplified, but that’s how a model works) from the evidence we see around us.

A given scientific paper may have a definite opinion on a matter. But summed over large numbers of scientists and studies the nature and degree of these opinions vary widely. Only by taking a summation of these opinions and applying them to this way of doing probability can we give ourselves the chance of making the correct decision. This is essentially how betting works, for example, when it is not entirely chance based (like horse racing). With a math stat masters, I would hope you would understand that outcomes are not all weighted with the same probability.

The videos are not saying ‘forget about whether the argument is right or wrong’. They are saying ‘we don’t know whether the argument is right or wrong and we never will for certain. However we do know that certain people with experience in the fields important to the decision are giving us evidence pointing us towards a closer probability to right than wrong, so as they have more experience with the fine details we should use this probability to influence our decision.’

PS I agree with you about Pascal’s Wager. However, that doesn’t work not because the method is flawed but because there’s no way of skewing the argument – the matrix remains 4 outcomes which we don’t know the probability of. Here, we can clearly pick up evidence that changes the size of each cell in the matrix, making this method a very useful way to making a decision. And the more experiments and studies that are done, the clearer those outcomes become.

http://plato.stanford.edu/entries/pascal-wager/

Since when did science become a “forget about whether the argument is right or wrong, just act the way I tell you to becasue you don’t have enough time to decide…” scare tactic debating technique?

This argument wouldn’t get past the critical eye of a 12th grade statistics class.

You can believe in global warming and advocate change, but if you are doing so because of this presentation, please take my word for it… the lottery is NOT a good way to get rich!

ps. i have a masters in econometrics and math stat, so i understand the flaws in his presentation just fine, and I don’t think he deserves respect becasue anyone who calls himself a science teacher shouldn’t be passing off this bunk as science.