text: Yes, climate really does change. It was likely just as warm during the Roman warm period 2,000 years ago . . . followed by the Medieval warm period 1,000 years later. Global mean temperatures have since been rising in fits and starts since the little ice age ended about 150 years ago. Overall, this amounts to about 1.5 F since the mid-1800s averaging about 0.1 F per decade. Recent increases have been less than half of the rate predicted by more than 100 IPCC computer models.