To what extent are temperature levels changing due to greenhouse gas emissions?

by J.K. Dagsvik & S.H. Moen,  Nov  2023 in  StatisticsNorway


Weather and temperatures vary in ways that are difficult to explain and predict precisely. In this article we review data on temperature variations in the past as well possible reasons for thesevariations. Subsequently, we review key properties of global climate models and statistical analyses conducted by others on the ability of the global climate models to track historical temperatures.

These tests show that standard climate models are rejected by time series data on global temperatures. Finally, we update and extend previous statistical analysis of temperature data
(Dagsvik et al., 2020). Using theoretical arguments and statistical tests we find, as in Dagsvik et al.(2020), 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.

Keywords: Global climate models, Climate change, Temperature analysis, Fractional Gaussian noise,
Long-range dependence

The Earth Is Mildly Warming, But Is CO2 The Cause?

by H.W. Jenkins, Nov 6, 2023 in ClimateChangeDispatch

If this column has ever plagiarized itself, it’s by repeating the phrase “evidence of warming is not evidence of what causes warming.”

A paper published by the Norwegian government’s statistical agency, written by two of its retired experts, touching on this very subject has called forth so many shrieked accusations of climate apostasy that you know it must be interesting.

The authors ask a simple question: Are computerized climate simulations a sufficient basis for attributing observed warming to human CO2? [emphasis, links added]

After all, the Earth’s climate has been subject to substantial warming and cooling trends for millenniathat remain unexplained and can’t be attributed to fossil fuels.

As statisticians, their conclusion: “With the current level of knowledge, it seems impossible to determine how much of the temperature increase is due to emissions of CO2.

Wow. For all the abuse dumped on them for this modest observation, and even some apologetic hemming and hawing from the government-run Statistics Norway, the authors don’t say climate models don’t make useful predictions.

Their predictions are useful precisely for testing the validity of climate models. What’s more, many concerned about climate change have no trouble seeing the problem as a matter of risks rather than certainties.

This includes coauthor John Dagsvik, who told Norway’s Aftenposten newspaper he favors emissions curbs for precautionary reasons.

The correlation-to-causation puzzle is hardly the authors’ invention, having bedeviled the oracular Intergovernmental Panel on Climate Change (IPCC) since its founding in 1988.

But unrestrained name-calling is required, the critics say, because anything that undermines confidence in climate models undermines progress against climate change.