“..since we are looking at a period of about 3 decades as being the main ‘signal’ from CO2 forcing, we don’t really know how to do the attribution problem on this time scale.” As usual, JC identifies the problem. People (and governments), however, want answers. It’s answers that sell papers, provide grants, give politicians (and pundits) their talking points. Hence the connection to religion, too. Religion gives answers to unanswerable questions. IPCC may be a one trick poney, but it gives the answers people demand. And that answer sells papers, provides grants, and gives politicians and pundits their talking points. It may even be correct, but we won’t know for a long, long time. Whatever the definition and nature of climate variability, periods of global warming (and cooling) occurred regularly before CO2 forcing played a role. Those periods of warming, statistically similar to the recent 1978-1998, and the generally similar 19th and 18th century warming compared to the 20th, make me doubt the confidence levels of the IPCC and others who attribute recent warming to AGW forcing because it also implies the same high confidence level that those unknown or poorly understood forcings responsible for earlier warming and cooling are no longer in play. I doubt that very much.