Warming and Cooling cycles are natural... what we're ooncerned with is whether the contribution of human activity is enough to tilt that cycle in a direction that's disadvantageous to us.
There's a certain elasticity and resilience to the biosphere... one which allows it to recover after extremely hot or cold spells. But human activity has reduced the variety of Earth's biota... including a huge portion of it which acts to regulate planetary climate.
The question is... will the combination of the reduced ability of the biosphere to influence global temperature, along with man's increased ability along the same lines, lead to a situation from which recovery becomes problematic?