Today in the Alps it is -2 at the top of the mountain and 4 degrees in town. So what is the actual temperature in Chamonix? The reason for this post is that on Wednesday it will apparently reach 20 degrees in town, having been 1 degree in the morning, while still being below freezing up where they are skiing. This degree of variation in a single town on a single day gives lie to the idea that we can measure the average temperature of the whole world to within 0.1 degree, not only today, but over thousands of years and predict it into the future. On such false precision we are making huge economic decisions...