Thursday, 17 October 2013

Really simple climate change

My background is chemistry, one of the most experimental sciences. No doubt that’s why I look at the empirical evidence when it comes to claims made by other sciences.

Unfortunately it seems to me that far too many pundits, both amateur and professional, rely on arguments from authority instead of empirical evidence when comes to climate change.

Of course climate experiments have an inevitable tendency towards ambiguity because climate is not a great subject for experimental science in that none of the variables can be controlled.

Yet to my mind, this is still where the climate debate should begin – experimental design. If scientists make claims about a causal link between some climate parameter and global temperatures then we should surely demand a repeatable experiment to support those claims.

Yet how do we design a controlled empirical trial of climate change theories when we can’t control any of the variables?

A really simple approach
Suppose we confine ourselves to inventing a simple trial of global temperature prediction which may be applied to any climate theory.

For example, we could say that global temperature predictions must be accurate over a period of thirty years – at the moment that would be from 1983 to 2013. I suggest thirty years because the climate appears to be crudely cyclical and some of the cycles may be long. Even thirty years is much too short, but it will do for falsification if not verification.

Therefore, according to this really simple test:-

Anyone who in 1983 predicted a pattern of global temperatures which in 2013 has turned out to be correct, then their theory passes our test. Whatever theory they used. Evidence might be a paper published in 1983 or earlier, or maybe even a newspaper article.

As far as I know that’s nobody.

No matter – we can easily shift the test period by five years. So anyone who in 1988 predicted a pattern of global temperatures which in 2018 turns out to be correct, then their theory passes our test. Whatever theory they used.

As far as I know that’s nobody again – no need to wait until 2018.

And so on and so on. In my view we don’t set the bar anywhere near high enough to assess the performance of climate theories. Yet demanding real world performance is no different from checking the fuel consumption claims of car manufacturers.

As with all things climate-related there are caveats, but one attraction of such a robustly empirical approach is that anyone may take personal ownership of their stance on climate change. There is no need to be browbeaten on this issue – it doesn’t require scientific qualifications or even expertise. Do you need engineering expertise to measure the fuel consumption of your car?

We turn around the usual relationships with climate scientists with: don’t tell me – show me. We also create a more level playing field for alternative climate theories and that is surely the most interesting aspect of raising the bar.


Mark Wadsworth said...


Another theory I am working on is that there have been periods in recorded or at least reconstructable human history when temperatures went up and periods where temperatures went down.

The down swings tended to be sharper, largely because of large volcano eruptions, but there was a fairly sharp upswing at the end of the last ice age (July 19th, although nobody knows which year).

By and large, humans adapted or coped quite well in the upswings and the downswings were a complete disaster.

There, that's my theory and I'm sticking to it. History tells us that we can cope with rises quite well, they are nothing major to worry about.

John Page said...

Deben with his RC background is one for quoting sacred climate texts rather than looking *coolly* at the evidence.

A K Haart said...

Mark - I agree - warming is beneficial. Yes there are caveats, but there are a range of positives with agriculture to the fore.

John - yet it isn't difficult. If we enter a cooling phase, which some would say is already with us, then how long will it be before these clowns admit the fact?

Demetrius said...

My great uncle Hugh, alive and working in 1883, when I was very young told me that the weather was always unreliable and so unpredictable. Anyone who claimed to "forecast" it more than a couple of days ahead was not to be trusted.

A K Haart said...

Demetrius - in many ways that's the most astounding aspect of the whole game. How anyone would dare to make climate predictions decades into the future is amazing.

Degringolade said...

Oh, and since it is foggy and damp here, and the garden is in the process of returning to mulch, I took the time to write a little screed.

Since I spoke of you and your writings on this blog, I am giving you a heads up.

Keep up the good work.


A K Haart said...

John - thanks for the mention. I'll put you on my radar. It's wet here, but mild - at the moment.