Wednesday, 6 October 2010
HOW ACCURATE ARE COMPUTER CLIMATE MODELS?
No doubt the scientists behind them would rather we did not have the answer, but in fact it is 50 years since the first predictions were made and so there is now hard evidence available as this article shows. On reading the evidence it becomes clear that the predictions have not been fulfilled. It points to the conclusion that it is impossible to predict the climate, which is born out by the accuracy of short-term forecasts, as we all know.
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Thanks for the tip Saya - but I note that you only have 4 followers on your site and I have 41.
ReplyDeleteHi Derek, long time no speak. Apologies, PhD has taken over my life. First-off - I think saya might be spam.
ReplyDeleteSecond, just want to pick you up on "it is impossible to predict the climate, which is born out by the accuracy of short-term forecasts."
So why is it possible to roughly predict temperatures in 6 month's time? Answer: the difference between climate forcing and weather. You're talking about two different things there - comparing weather and climate doesn't work.
Your sentence is a bit like saying "its impossible to tell whether the tide is coming in or going out - as is born out by how variable each wave is." It's just the wrong level of comparison.
Tata for now, hope to catch up more in future.
Good to hear from you, Dan. The article which I linked to explains that we now have 50 years of data which can be compared to the predictions made at that time - the reult is that the predictions were wrong. Now you can argue, if you wish, that this is not long enough, but I would say that this is the best comparison that is available. If we need to wait a thousand years, or, perhaps a million, then we are simply having a pointless discussion, like discusing the meaning of life.
ReplyDeleteIn answer to your point about predicting the temperature in six monthe time - (a) this is pretty short term and so is probably 'weather' not climate, and (b) it depends on what you mean by the temperature - do you mean the temperature on that particular day? In which case you are more likely to get it wrong, or do you mean the average temperature in a particular place, in which case you may also be wrong, or do you mean the average global temperature - in which case you will probably be right as it has only varied by 0.7C in the last century according to the 'official' figures. Mind you measuring this in a meaningful way is a mine field of problems as we both know.