[Skybird]

https://www.ssb.no/en/natur-og-miljo...339/DP1007.pdf

In this paper we have reviewed data on climate and temperatures in the past and ascertained that there have been large (non-stationary) temperature fluctuations resulting from natural causes.
Subsequently, we have summarized recent work on statistical analyses on the ability of the GCMs to track historical temperature data. These studies have demonstrated that the time series of the difference between the global temperature and the corresponding hindcast from the GCMs is non-stationary. Thus, these studies raise serious doubts about whether the GCMs are able to distinguish natural variations in temperatures from variations caused by man-made emissions of CO2.
Next, we have updated the statistical time series analysis of Dagsvik et al. (2020) based on observed temperature series recorded during the last 200 years and further back in time. Despite long trends and cycles in these temperature series, we have found that the hypothesis of stationarity
was not rejected, apart from a few cases. These results are therefore consistent with the results obtained by Dagsvik et al. (2020). In other words, the results imply that the effect of man-made CO2 emissions does not appear to be sufficiently strong to cause systematic changes in the pattern of the temperature fluctuations. In other words, our analysis indicates that with the current level of knowledge, it seems impossible to determine how much of the temperature increase is due to emissions of CO2.