The web tells me this is from the Bible, Luke 15:7 to be precise. So what will cause an atheist like me to quote the bible? In this case it is of course a sinner repenting. Fellow physicist Prof Richard Muller of the University of California Berkeley to be precise.

In the past Prof Muller has been critical of climate scientists, and has questioned the strength of the scientific case for global warming. For an example see a 2004 article of his. Of course there are many people out there denying the numerous analyses of a lot of data that shows global warming. And many of them are, like Muller, scientists but not climate scientists. But Muller is different. He actually went and actually analysed the data – gigabytes of climate data is freely available for anyone to download.

And his conclusion? Virtually identical to those of professional climate scientists. The BBC article on his announcement of his repentance has a graph of temperature versus time for his analysis. His curve is basically on top of other analyses, and shows a clear upward trend.

Being an atheist I am not qualified to say if heaven is rejoicing, but understandably there is some polite rejoicing by climate scientists, for example at the realclimate blog. I guess the moral of this is that if you actually look at the data, and do a competent analysis of it, you find what everyone who has done that finds, which is that our planet is getting warmer.