On Fri, Nov 30, 2012 at 08:08:26AM -0500, Roger Clough wrote: > Hi Russell Standish > > Thanks. Causality has enormous importance, especially > if you can differentiate it from correspondence. > > I sometimes think that the rise of the stock market is > causally related to the price of gold. Or the value of the dollar. > Historical inflation of the value of the dollar at least corresponds > to the tonnage of gold mined over the years. > > Politicians, depending on which point of view they want > you to believe, generally make false claims of causality. > A particular case in point is the question of whether > tax cuts enrich the economy. > > And I wonder if there are studies that differentiate > global warming/ CO2 as a correlation or is casual. > > Another one is whether Israeli attacks on Palestine > are cause by Palestinian attacks on Israel or > vice versa. A timeline study of attacks should show this. >
Interesting you should mention this. There's an article I was just reading in New Scientist (4th August, p32, titled "Ruined") that was reporting on a study by David Zhang linking climate change to agricultural production, food price, population size and frequency of wars in Europe during the period 1500-1800. This study used Granger causality, not correlation, so really teases out cause and effect between these time series. The actual paper referenced is PNAS, vol 108, p17296. As far as I'm aware, the link between CO2 and temperature is one of correlation - equivalent Granger causality analyses have not been done. But I could be wrong on this. Granger causality is still not widely known - so people do tend to fall back on simple correlation. In any case, it will be tricky with CO2 and temperature, as causality flows in both directions, since there's a positive feedback - warmer temperatures releases stored carbon into the atmosphere, which then drives temperatures. The classic graphs that Al Gore showed in his movie were later shown to have CO2 level timeseries lag that of the temperature timeseries, indicating the significance of the stored carbon release effect. Cheers -- ---------------------------------------------------------------------------- Prof Russell Standish Phone 0425 253119 (mobile) Principal, High Performance Coders Visiting Professor of Mathematics hpco...@hpcoders.com.au University of New South Wales http://www.hpcoders.com.au ---------------------------------------------------------------------------- -- You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to everything-list@googlegroups.com. To unsubscribe from this group, send email to everything-list+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/everything-list?hl=en.
