Like a warming ice sheet, or a fracked rock, the so-called “consensus” on global warming is starting to crack. The latest IPCC report is in many ways a remarkable document.
Many people will be astonished at the IPCC’s assertion that they are now more certain that climate change is man-made than they were when their last report was published six years ago. 95% certain now, as against 90% certain then. And this despite the fact that there has been no increase in mean global temperatures in the meantime, and that the predictions of their computer climate models have quite simply failed.
It is perhaps not surprising that if you assemble 1000+ “scientists” and ask them to look for evidence of man-made global warming, they find some — or at least they report that they have found some. (I put “scientists” in inverted commas, because on their previous report it was found that a significant proportion of the IPCC “experts” were not scientists at all, but green campaigners and eco-activists — and many of the “peer-reviewed papers” quoted by the IPCC turned out to be merely press releases and propaganda from green NGOs. And of the genuine scientists on the panel, many were from unrelated disciplines, like the Chairman of the IPCC, Ravendra Pachauri, who is a railway engineer).
It is really rather worrying that they seem to have a curious approach to science. The first thing that a scientist will do on examining a phenomenon is to make sure he has a phenomenon to examine. Is anything abnormal happening to the Earth’s climate? Anything that requires an explanation? No, there is not. The slight warming in the last 150 years is entirely consistent with the well-established, long-term natural climate cycles that gave us the Roman Optimum and the Mediæval Warm Period. We are recovering from the Little Ice Age, and appear to be moving into a new, 21st Century Optimum.
This tends to validate the “null hypothesis”, that nothing unusual or unexpected is happening, and that therefore there is nothing for the IPCC to explain. They say they are 95% confident that the warming since the mid-20th Century is man-made. Would they like to tell us about the warming in the previous 100 years? Why is warming after 1950 man-made, but not warming before 1950?
The use of computer models is not science. It is little more than formalised guesswork. You plug in your assumptions, turn the handle, and see what comes out. Put the wrong assumptions in, and you’ll get false predictions coming out.
So the models are not scientific. But we can apply the scientific method to the question of whether the models work. Science works by establishing hypotheses and testing them. Let me offer you the hypothesis that the IPCC’s models produce credible and valid predictions of future climate trends. We can test this hypothesis. The image above shows the IPCC’s various predictions of mean global temperatures. The blue line shows the actual, measured temperature. So the hypothesis is falsified. It is just plain wrong. The IPCC’s climate models cannot be trusted. Yet we are investing hundreds of billions on green policies based on their predictions.
Another profoundly anti-science element of the IPCC report is their spurious pretension to precision, in claims of 90% and 95% certainty. I have a maths degree from CambridgeUniversity, and a passing familiarity with the science of statistics. The term “95% confidence level” has a clearly defined meaning in statistics. It depends on looking at the distribution of a wide range of data points. Here we have only one case in point. In fact in a sense we have none, because we are seeking to predict the future, and we have no way of knowing if we are right, apart from waiting to see. So the IPCC’s “95% certain” is no more than a bunch of guys sitting round a table and saying “What’s your guess? How do you feel about it? A bit more certain than last time (despite the lack of warming in between)?” The answer is Yes, they do feel a bit more certain (or their political masters want it to appear so). And they said 90% last time, so it’s 95% this time. Will it be 97.5% in 2018? This is an abuse of terminology, and I am surprised and disappointed that so-called scientists would engage in it.
A question at the heart of the climate debate is the sensitivity of the climate to atmospheric CO2. The IPCC is obliged to assume very strong positive feed-back effects to get to its high sensitivity and alarmist predictions, though it cannot demonstrate those feed-back effects, and many scientists point to potential negative feed-backs. Interestingly, this IPCC report seems unable to give a best estimate of climate sensitivity. But the flat global temperatures over the last sixteen years strongly suggest that climate sensitivity to atmospheric CO2 is much lower than the figures the IPCC likes to use.
The IPCC has failed to explain the long pause in global warming. It has failed to explain the clear failure of its climate models. But it asks us to keep the faith in defiance of the evidence. Fewer and fewer of us will be prepared to do so. We have looked at the Emperor, and we have seen that he has no clothes.