Thomas Piketty has responded in detail to the FT's criticism of the wealth inequality statistics in his Capital book (see earlier post on this) - click here. Wealth inequality data is much harder to collect than income inequality data for the long run. My paper on wealth inequality in Ireland over the period 1858 to 2001 uses probate data to measure wealth inequality. The findings of my paper agree with Piketty's view that wealth has become more concentrated over recent decades.
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.