I suggest you examine this chart: https://en.m.wikipedia.org/wiki/File:65_Myr_Climate_Change.png https://en.m.wikipedia.org/wiki/File:65_Myr_Climate_Change.p..

I suggest you examine this chart: https://en.m.wikipedia.org/wiki/File:65_Myr_Climate_Change.png https://en.m.wikipedia.org/wiki/File:65_Myr_Climate_Change.p... Which is taken from this excellent Wikipedia article: https://en.wikipedia.org/wiki/Geologic_temperature_record https://en.wikipedia.org/wiki/Geologic_temperature_record A change of 1.5C is just a nudge in the direction of historical averages.