".......everyone knows that forecasting is notoriously difficult - particularly about the future"
Your words bell
And in a previous post you quote an article by Ross Garnaut which, in part, says:-
"A failure to act here, accompanied by similar paralysis in other countries, would see our grandchildren living with temperature increases of around 4 degrees celsius this century"
That sounds like a forecast to me.
It would appear you're only wanting to believe certain forecasts.
