My colleague and former PhD student Gareth Campbell has created a website about the British Railway Mania - click here. This episode has been described by the Economist as probably the greatest bubble in human history. Gareth's website provides background on the Mania and posits some explanations for the 'bubble'. In his explanation of why the bubble happened, Gareth places a lot of emphasis on investor myopia regarding future dividends and uncalled capital. His study of investors during the episode does not support the view that this episode was fuelled by naive and irrational investors.
The Berkeley Earth Project , an independent study of global warming, has found that the earth has become a degree warmer over the past half century. However, the statistical uncertainty surrounding pre-1920 estimates makes it very hard to say much about long-term trends - click here for graph . This is one of my concerns with the global warming debate - we simply don't have trustworthy long-run data which looks at temperature changes over the last millennium (or two). My second concern with the global warming debate is that it is very hard to prove any sort of casual link between global warming and human activity. The scientists may be able to show correlation between global warming and our production of carbon dioxides etc., but correlation is not causation. My third concern with the debate is that those who are sceptical or agnostic are stereotyped as flat-earthers or intellectually-challenged crackpots. This only stifles debate and the progress of science itself.