Climate Model Failed

By Andy May

On January 22, 2021, John Christy presented a new online talk to the Irish Climate Science Forum. The talk was arranged by Jim O’Brien. A summary of the presentation can be read at here. In this post we present two interesting graphs from the presentation. These compare observations to the IPCC Coupled Model Intercomparison project 5 climate models (CMIP5, 2013) and CMIP6 (current set of IPCC models) climate model projections.

Figure 1. CMIP5 models versus weather balloon observations in green. The details of why the models fail statistically can be seen in a 2018 paper by McKitrick and Christy here.

The next graph compares the newer CMIP6 models to both the weather balloon data (light green) and the weather reanalysis data (dark green).

Figure 2. CMIP6 models versus weather balloon data in light green and weather reanalysis data in dark green.

The difference between the models and the observations is statistically significant and shows that the models have been invalidated. It is also significant that the CMIP6 spread of model results is worse than the CMIP5 spread. Thus, the newer models show less agreement to one another than the previous set.