I't often stated that the rate of change of global surface temperature experienced last century is unprecedented? How can we say it is unprecedented over geological time since we only have about 200 years of records (i.e. totally irrelevant)?

We know that there have been much more rapid changes over large regions in the past. For example, Greenland, Iceland, Ireland warmed from near glacial temperatures to near current temperatures in 7 years 14,600 years ago and in 9 years 11,600 hears ago. And guess what. Life loved it. Life thrived in the warming periods. See Figure 15:21 (p391) here: http://eprints.maynoothuniversity.ie/1983/1/McCarron.pdf

I am not persuaded there will be any net damage to the planet from GHG emissions this century. I'll support policies to mitigate GHG emissions only if they are economically beneficial for the whole world irrespective of any projected climate benefits. This can be achieved, but is blocked by the so called 'Progressives'.