It was ice, not global warming, that killed and entombed millions of mammoths and woolly rhinos in Siberia and Alaska.

It was unrelenting cold and then ice, not global warming, that forced the Vikings out of Greenland.

It was bitter winters, not heat waves, that finally defeated the armies of Napoleon and Hitler in Russia.  George Washington's army also suffered from an unusually bitter winter at Valley Forge in 1778, in the depths of the Little Ice Age. 

Snowy blizzards periodically kill more cattle than heat waves in Colorado, South Dakota, and Texas.

When the Tambora volcano exploded in 1816, it spewed massive volumes of ash and "greenhouse" gases, including carbon dioxide, into the atmosphere.  There was no global warming from the greenhouse gases, but the heat-blocking ash-filled atmosphere and a quiet sun caused "the year without a summer."  Failed crops and famine stalked Europe, Asia, and America. 

It is icebergs, not warm oceans, that sink ships like the Titanic, and spreading sea ice trapped "The Ship of Fools" in Antarctica. 

Every major geological era has ended with massive volcanism on land and under the seas.  Molten lava heats the seas, and eruptions on land fill the atmosphere with dust, which blocks incoming solar energy.  There is rapid evaporation from the warm seas followed by rapid condensation in the cold, dark atmosphere.  This process dumps massive snowfalls, which become ice sheets on land, starting a new ice age and bringing the extinction of many species.

It is lethal global cooling we need to fear, not life-sustaining global warming.