says who? again in that respect we have a data set to refer to of exactly zero..its pure supposition..there has been 100+ years of warming without any collapse of ecosystems..which goes against what the doomsayers have been saying for the last 40 years ...i 100% guarantee that in 40 years time you will still be able to honeymoon in the Maldives and wont be wading through the streets of London knee deep in water. i also guarantee in 40 years we will have technologies at hand you cant even think or imagine today.