[Tinordi]

Overall, the takeaway from Dr Muller’s presentation of his team’s data is that, in the words of one climate scientist, a “Koch-brothers-funded study confirms the previous temperature reconstructions.” Dr Muller says the team will now be looking into a number of other effects, including the bias that the “urban heat island” effect—cities are warmer than surrounding countryside—might have. The question of good versus bad location is linked to this (a good site can become bad as a city sprawls over it) and so is the issue of which records you choose to use (long records, preferred by earlier reconstructions, may be more prone to changing urbanisation around them). But there is more to the problem, and Dr Muller hopes to look into it further, as well as into issues that might arise from the times of day at which observations are made, stations moving from one place to another, and changes in the instrumentation used.

The Berkeley work, especially after it is published and disseminated in full, may increase the acceptance of the reality of global warming among people who have so far managed to maintain a comforting and sometimes self-serving feeling that maybe the people who deny that anything is going on are actually right. It doesn’t in itself show how much of the warming is due to human activity. Dr Muller, in a somewhat cavalier way, chose to suggest that about half of what had been seen since 1900 was. Other scientists would put the proportion higher.

http://www.economist.com/blogs/babba...climate_change