How to navigate in the climate fog

If we are to navigate in the climate fog, there are three important questions to address, which are related to one another. These are: (1) Have global temperatures increased over the past 175 years or so, (2) if yes, is the increase wholly or partly human-caused, and (3) is it dangerous to health and society?

Translation of my previous post in Norwegian.

The first question is the easiest to answer. Yes, global temperatures have increased, but is the change entirely or partly man-made? Personally, I find it difficult to believe that it is entirely man-made, and the reason is that the climate remained unusually cold for several hundred years until about 1850, a period referred to as the Little Ice Age. A temperature rise after such a period is not unexpected if one assumes a long-term, constant trend with natural variations.

But if not entirely, could temperature increases then be partly man-made? Well, I can’t rule it out, but the best empirical evidence I know of speaks against that hypothesis. I’m referring to a Statistics Norway note by John K. Dagsvik and Sigmund H. Moen – an update of their study in the prestigious journal Journal of the Royal Statistical Society – where they removed noise about possible causes of climate change (man-made or not) and only studied whether temperature increases could be explained as natural variations. Data were taken from 96 weather stations across 32 countries, where the time series were long and had few missing observations. Dagsvik and Moen employed what is known as ARFIMA modeling (not to be confused with ARIMA modeling), or autoregressive fractional integrative moving average, to investigate whether long-term temperature increases are natural variations or not. The conclusion was that “the effect of man-made CO2 emissions does not appear to be strong enough to cause systematic changes in the temperature fluctuations during the last 200 years.” In other words, long-term temperature increases can, in most cases, be attributed to natural long-term variations.

Perhaps as expected, the criticism was not long in coming, and in my opinion, the loudest voice was Rasmus Benestad at MET, stating that “It is wise to be humble when moving into an unknown field … especially because the matter concerns a discussion paper.” To address the last issue first, as I pointed out above, this is about more than a discussion paper; a study originally published in a highly respected journal. When it comes to moving into an unknown field, Dagsvik and Moen indeed know what they are talking about. But does Benestad know what he is talking about? How much does he know about autoregressive fractional differentiation with moving averages, if he has even heard of it and understands anything about it? And has Benestad or others pointed out that Dagsvik and Moen have made mistakes in their calculations? That I have heard, probably because they are not qualified to comment on it. It would therefore have been nice if Benestad and his like-minded people – there are perhaps several hundred in Norway alone who call themselves climate scientists with good tax-financed jobs and project funds – had faced the two independent researchers with little or no funding in a constructive, perhaps even humble way. But no.

So, to the last question: Is climate change, primarily temperature increases, man-made or not, a danger to humanity? They are not, as I have addressed in previous posts. I have also refuted the claim that the heat wave in the summer of 2022 was responsible for many deaths in Europe. Regarding future scenarios, where one projects about tomorrow’s climate with ditto disasters, that type of activity cannot be characterized as anything other than prediction, at best, pseudo-research.