Where I sit, there was once an ice sheet 2 km thick. It turned the Missouri River south and left a surface geology replete with chunks of Canada, some as large as a full sized van.
Every winter we are reminded what cold is about, with subzero temperatures and the occasional blizzard or two, and from time to time, people freeze to death out of misfortune, ignorance, or lack of respect for what the weather can do.
Certainly, if the current energy policies of the US and the world, heralded as the cure for global warming (under the heading of "climate change"--cold never seems to be a worry) are allowed to continue their trajectory, much of humanity would inevitably perish in the event of an ice age. Not only would we lack the ability to grow enough food, but we would be seriously hobbled in our ability to adapt to the need for more heat in order to stay alive. Without energy, none of the infrastructure necessary to human survival could be constructed in time to ward off massive human die-offs.
If such an event were to start tomorrow, we would have to first recognize it was happening through the clutter of research still alleging the opposite was true, and then the fact would have to be universally accepted well enough to mobilize resources against the new threat. Under ordinary circumstances there is a significant inertia present in science, where new ideas are slow to gain traction, and must be reviewed and research repeated in order for acceptance to become general in nature. Then, and only then could the pursuit of remedies be made. Note that that is slow enough in a system of thought unhampered by heavy political considerations, but the ability to react in a timely fashion would be much more severely retarded by those who would exert political power to silence those who attempted to bring such a problem to light.
In the present political climate, we'd die like flies in a sudden frost.
