"Pete L" wrote:
Just looking at the figures on the above link.....

Can anybody explain how and why two significant decimal places are
considered? As far as I recollect an ordinary mercury thermometer is
accurate to 0.2 deg. So to suggest global mean temperatures are 14.31
degs seems totally meaningless. I would have though just 14 degs is
enough without trying to invent a greater accuracy.

Pete, the fact is that the 14.31 is not a real temperature. It
involves not only temperature, but also time and space. It is,
perhaps, best to regard it as an index of planetary warmth or
coldness over a given period. Some might even argue that it serves
only to confuse that it looks like a temperature, and that giving it
a unit (i.e. °C) adds to the confusion. The accuracy of individual
thermometers and the precision to which they may be read
are neither here nor there.

Philip