Rud Istvan’s comment [format edited for clarity] explaining Gavins Schmidt’s histogram version of Christy’s CMIP/Observation comparison:
The histogram can be explained in less than one minute to a nontechnical audience.
- Point to leftmost bar.
- ‘the lowest of the CMIP5 runs , this one model out of 102, had an annual rate of increase from 1979 to 2015 of 0.008C/yr.’
- Point to tallest bar.
- ’23 models had an average rate of 0.018.’ Wave at the right side. ‘Many models had rates that were much higher.’
- Now vertically wave at the colored horizontal lines, at the dots.
- ‘The various satellited measured actual rates are lower than almost all the models’.
- Then wave horizontally at the colored horizontal bars.
- ‘That is even true considering the uncertainties in the various satellite measurements.’
- Then wave again at the right side of the histogram.
- ‘So we see that the models have generally run much hotter than reality over the past three and a half decades.
- That is why it is hard to have any confidence in their longer term temperature and sensitivity estimates.’