Those who have been following this series know the drill. Viscount Monckton is replying to my Recognition statements. I respond in bold. If he has further contributions they will be in italics. The previous posts in this series are here, here, here and here.
4. Conventional physics accurately describes how greenhouse gas concentrations can contribute to warming.
(VM): “Once again, the question is not expressed quantitatively and cannot, therefore, be answered definitively in scientific terms. It is trivially true that adding a greenhouse gas to an atmosphere such as ours will – all other things being equal – be expected to cause some warming. The results of Tyndall’s experiment are not up for repeal.
TF: Again, given the nature of the climate debate I do not think this is trivial. You and I are both called ‘deniers’ because the alarmists maintain that we do not accept what you call a ‘trivial truth’. (Although I guess I have recently been promoted–they are more likely to call me a ‘delayer’ or ‘mitigation skeptic’ than ‘denier’.)
The purpose of this exercise is to find out if mainstream science is accepted by the honorable opposition–the skeptics (and lukewarmers). Throughout this series of posts you have shown that you do accept it. As I hinted at yesterday, it is far easier to make a case than to build the courtroom.
The real scientific questions are whether all other things are equal, and how much warming a given greenhouse-gas enrichment will cause. The uncertainties, already formidable, are greatly aggravated by the fact that the climate behaves as a mathematically-chaotic object: that is, it behaves deterministically but indeterminably. Everything happens for a reason, but without unattainably well-resolved initial data we cannot predict what will happen or why (Lorenz, 1963; Lighthillk, 1998; Giorgi, 2005; IPCC, 2001, §18.104.22.168).
Take the question whether all other things are equal. If the world warms, more evaporation occurs, chiefly from the oceans. But evaporation cools the surface and transfers heat upward, particularly via the mechanism of tropical afternoon convection. From the upper atmosphere, some of that heat will radiate harmlessly to space. The rate of surface evaporation – and the corresponding cooling effect – turns out to be thrice the rate per Kelvin of warming that the models had assumed (Wentz et al., 2007). And that is just one of numerous examples one might take.
TF: Yes,and there are even more factors at play than those you cite. It is a complex subject. But it is being studied by a host of scientists and more is being learnt about it every day. These are by and large the scientists whose opinions you do not care to consider.
And what of the quantitative determination of the warming influence of CO2? Monckton of Brenchley et al. (2015), in a revealing paper in the Science Bulletin of the Chinese Academy of Sciences, report that the coefficient in the CO2 forcing equation, and hence the magnitude of the forcing itself, was reduced by 15% between the IPCC’s 1995 and 2001 reports. They also report that the IPCC has reduced its central estimate of the temperature feedback sum (which accounts for two-thirds of all global warming in the IPCC’s understanding) from 2 to 1.5 Watts per square meter per Kelvin since 2007. These two influences on their own require climate sensitivity to be halved.
TF: Would you not consider that as evidence that a) science is progressing and b) that the climate science mainstream is willing to publicize previous errors and corrections that work against their primary hypothesis?
There is also the question how much net forcing our emissions will cause. In 1990 the IPCC estimated that by now the total anthropogenic forcing should have been 4 Watts per square meter:”
(VM): “However, by 2013 the net anthropogenic forcing had been reduced by almost half, to just 2.3 Watts per square meter:”
(VM): “Manifestly, then, the quantitative impact of our influence on the climate via emissions of greenhouse gases is perforce poorly constrained. We do not have any idea how much or how little influence we are having. All we can go by is the growing disparity between rising greenhouse-gas emissions and relentlessly static global temperatures, and between the models’ excitable predictions and far less exciting reality:”
TF: I agree that there is a lot of work ahead of us all in attribution and quantification. In a less politically charged environment this would be grounds for excitement. It is a pity that it all has become a partisan political issue. Both alarmists and skeptics have contributed to this polarization.
As for your final graph below, I would amend the title–the models have indeed failed, but they have failed to do what they were not designed to do. They are not meant to accurately predict future temperatures at a decadal level. They have done a good job at showing the broad sweep of climate over much longer periods of time and contributing to our understanding of the various forces at work in shaping it. If you criticize them for not doing what the alarmists had hoped they would do, you might spare a moment to praise them for doing a good job at what they were designed to do.