The HadCRUT series of world temperatures show that average world temperature
stopped rising around 2000, and if anything has been slowly falling since.
The question is not so much where the heat energy has gone (it has evidently
gone into beefing up the atmospheric circulation, both horizontal and
vertical) as why temperatures stopped rising when they did. What happened
around 2000 to cause that change?

Ian Bingham,
Inchmarlo, Aberdeenshire.