On Climate Change
There are constant (and somewhat annaoying) debates about whether climate change is really happening. The best way to tell in my opinion that I read recently involves long periods of ‘record collecting’ and the harmonic series. What is he on about you may wonder?
Take an example. Annual rainfall in the UK. Data collection began in 1748 and clearly that year will have experienced record levels of rainfall by default. If rainfall is a random event unaltered by humans then the next year there is a 50 – 50 chance of there being a new record. Year three will have a 1 in 3 chance and so on. It turns out that the expected number of record years follows the harmonic series i.e. 1+(1/2)+(1/3)+(1/4)+(1/5)…+(1/n) up to the number of years we have been keeping track. This clearly grows very slowly and in the 256ish years since 1748 we would expect 6.12 record years. This was fine up untill 2004 but has started going significantly awry…
February 8th, 2010 at 8:20 am
I don’t think that people are arguing about whether or not climate change is real… it’s more what’s causing it that’s got people all disagreeing and stuff.
But isn’t that beside the point anyway? Surely recognizing a problem should be enough to try and do something about it…
And, about your rain record breaking point… It could be completely coincidental that these past few years have seen so many records… We won’t know until a significant time period has gone by to possibly show no records to “even things out” right?
February 8th, 2010 at 9:04 pm
Well the logic goes that the number of record breaking years can go above the expected number and people shouldn’t be too worried, but the probability of the record being broken repeatedly in a short space of time and being above the predicted limit is very small and more likely due to the mechanism no longer being a random event (i.e. human intervention). So we shouldn’t need more years of measurement to verify this. I have since looked into the same statistics for record cold winters and record warm summers and they also show the same ‘no longer random’ behaviour although with less certainty.
I agree though, the consequences of doing nothing are not worth the risk the doubters are taking…