On Climate Change
Sunday, February 7th, 2010There 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…



