Getting hotter
A new measure of global warming FOR those who question whether global warming is really happening, it is necessary to believe that the instrumental temperature record is wrong. That is a bit easier than you might think. There are three compilations of mean global temperatures going back over 150 years from NASA, the National Oceanic and Atmospheric Administration (NOAA), and a collaboration between Britain's Met Office and the University of East Anglia's Climate Research Unit (known as Hadley CRU). All suggest a similar pattern of warming amounting to about 0.9C over land in the past half century. Yet this consistency masks large uncertainties in the raw data and doubts about their methodologies. But a new study of current data and analysis by Berkeley Earth Surface Temperature offers strong support to the existing temperature compilations. The results, described in four papers still undergoing peer review, are released on October 20th. It estimates that over the past 50 years the land surface warmed by 0.911C: a mere 2% less than NOAA's estimate. That is despite its use of a novel methodologydesigned, at least in part, to address the concerns of what its head, Richard Muller, terms legitimate sceptics. The study will be published online with supporting data, merged from 15 separate sources, with duplications and other errors clearly signalled. At a time of exaggerated doubts about the instrumental temperature record, this should help promulgate its main conclusion: that the existing mean estimates are in the right ballpark. That means the world is warming fast. Read our full story