The Next Great Extinction Event Will Not Be Global Warming – It Will Be Global Cooling

WUWT
However, Excess Winter Deaths are not the worst threats to humanity. The glacial cycle averages about 100,000 years, consisting of about 90,000 years of the glacial period, when mile-thick continental glaciers blanketed much of the Northern and Southern Hemispheres including Canada, Russia, Northern Europe and Northern USA, and about 10,000 years of interglacial, the warm period of the present. Earth is now 11,500 years into the current warm interglacial, and our planet may re-enter the glacial period at any time.  ......
Increased atmospheric CO₂, driven by fossil fuel combustion and/or other causes, will have little impact on the onset of future glaciation. Climate is not highly sensitive to increasing atmospheric CO₂. Paradoxically, CO₂ concentrations are not alarmingly high; in fact, atmospheric CO₂ concentrations are alarmingly low – too low for the long-term survival of terrestrial life. Photosynthesis of C3 food crops ceases at 150ppm – CO₂ starvation."