A little while ago (before Cmas?) there was excitement about a Barnett study, reported at a conference, showing detection of an anthro signal in the worlds oceans. A Barnett study is available (here; thanks HET) but since this is from 2001 its presumably an earlier one. Anyway, to quote:
Application of optimal detection methodology shows that the model-produced signals are indistinguishable from the observations at the 0.05 confidence level. Further, the chances of either the anthropogenic or observed signals being produced by the PCM as a result of natural, internal forcing alone are less than 5%. This suggests that the observed ocean heat-content changes are consistent with those expected from anthropogenic forcing, which broadens the basis for claims that an anthropogenic signal has been detected in the global climate system.
A more recent paper (again in Science, this time lead by Hansen (see his comments about political interference with his press releases here)) is commented on by RC (by Gavin, since he is a co-author).
The Hansen paper gets tagged with the tedious "smoking gun" idea again, which I have come to believe is just not sensible. John Fleck touches on the point here, and says most of what I mean, but not quite in the same words. What I think is now clear is that the evidence, objectively considered, for anthro climate change is now somewhere between incontrovertible and very strong. But, in certain quarters, this doesn't matter, because its not objectively considered. For these people, who very strongly *don't* want to be convinced, there may well never be a "smoking gun" - because the "gun" is always a complex matter of observations and modelling that needs patience to understand: and if you don't have or want this patience, there will always be a septic out there with simple, easy-to-understand (but wrong) arguments for why there is no problem. There are, after all, still people who can't accept things like relativity - and there isn't even any politics/money tied up in that.