My former PhD student Will Quinn has a new QUCEH working paper entitled Squeezing the Bears: Cornering Risk and Limits on Arbitrage during the British Bicycle Mania. In this paper, Will argues that the risk of being cornered effectively resulted in constraints on short selling during during the British Bicycle Mania of the mid-1890s. These constraints on short selling made it very difficult for traders to correct overvalued shares in bicycle companies. Will's paper is one of the first to look at constraints on short selling during historical financial bubbles.
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.