Phil Jones still thinks that most of the global warming in the second part of the twentieth century is anthropogenic. But in his very recent BBC interview, he also acknowledges that the MWP may have been as warm, that there have been similar rises in temperatures in the past, and that there are many uncertainties:

Q”When scientists say “the debate on climate change is over”, what exactly do they mean - and what don’t they mean?

A. “It would be supposition on my behalf to know whether all scientists who say the debate is over are saying that for the same reason. I don’t believe the vast majority of climate scientists think this. This is not my view. There is still much that needs to be undertaken to reduce uncertainties, not just for the future, but for the instrumental (and especially the palaeoclimatic) past as well. “

The science is settled?

Mr. Jones does not seem to think so.

I believe a reasonable person can have less confidence than Mr. Jones continuing view about the probable causes of GW in in the 1990s. Data about the past and even the present leaves much uncertainty; there is limit in addressing a complex and unique system to how much understanding can be derived from controlled and isolated experiments in the way that hard sciences like basic physics progress; some of the causal factors in climate change are poorly understood. Others may be unknown or undiscovered. And the political biases of scientists matter because subject estimates of how much is unknown, for example, depend largely on intuition, not hard science, and that tends to be influenced by ideology.

The routine answers are not convincing. “The scientific principles are known.” Some trivial ones are: Co2 is a greenhouse gas. But even if they all were - and this is very doubtful - how simple principle interact with uncertain initial conditions in complex conditions is hard to predict and understand.

No more convincing are the familiar rhetorical tricks to hide the decline in reasons for believing the previous orthodoxy. You can characterize “sceptics are “deniers”; say they do not have arguments, only “talking points”. Much as this may strengthen group solidarity and deter the questioner, these are not devices that should sway anone interested in the substance of the debate.

You can keep saying the refereed publications are all in favour of AGW but what about the over 500 that aren’t; populartechnology.net ?)

As for the point that I have no right to an opinion because I am not a climate scientist, public policy (and court cases) are not decided by specialists, but lay people who listen to experts and arrive at their rational assessments of them. That applies to you who think the science is settled no less than me.

A peaceful and pleasant weekend to you all.