If you take the view that each is a separate attempt to model the earth's
climate over the period in question, then the ensemble is likely to be a better estimate of the world's climate than the individual runs, and the reduction in variance is simply an artifact of the fact that we have better information.
As an example, airlines are well known to protect themselves against significant rises in crude oil prices, by buying a futures contract today with a specified price and delivery date in the future, on the assumption that oil prices will be on the
rise over the period in question.
The artist's lawyers argued that the painting was the creation of another man, Pete Doige, who had been incarcerated at the Thunder Bay correctional centre where Fletcher
worked over the period in question.
In fact if you read Lindzen Illusions # 1 and # 2, you'll see that the
warming over the period in question is indeed consistent with 3 °C sensitivity (as will be discussed in LI # 4).
And by the way, from Q3 - 2003 to Q3 - 2014 GG's share count rose from 183M to 814M, so although its share price is up by «only» about 50 %, its market cap is up by about 580 %
over the period in question.