While most people still worry about global warming, I am more concerned about the next Ice Age. A glaciation would present a serious problem for survival of our present civilization, akin to a nuclear winter that many worried about 30 years ago.
Nuclear winter is all fantasy, of course; but ice ages are for real.
Natural warming of the Earth reached a peak 65 million years ago. The climate has been generally cooling ever since. Antarctic ice sheets started growing 25 million years ago. In the last 2.5 million years, the Earth entered the period of Ice Ages [the geological name is The Pleistocene] and has been experiencing periodic glaciations where much of the land was covered by miles-thick ice sheets.
We are approaching the likely end of the present warm inter-glacial, called The Holocene. It’s time to prepare for the next glaciation to see how we can overcome it – or at least postpone its onset. Human Caused Global Wa... Best Price: $6.62 Buy New $9.07 (as of 05:55 EDT - Details)
Although we don’t fully understand the gradual onset and sudden termination of each glaciation, their timing is determined by astronomical factors – the inclination and precession of the Earth’s spin axis. They control the amount of sunshine [solar energy] reaching northern latitudes. The mathematics was worked out by the Serbian astronomer Milankovitch, but the physics is not yet certain.
It is currently believed that a glaciation gets underway when a northern snow field [at latitude of about 65 degree N] survives during the summer and then gradually grows into an ice sheet.
The survived snow field acts as a “trigger” for commencing a glaciation. Its growth into an icesheet is conditioned by the “feedback” as it reflects solar radiation and thus resists being melted by solar energy in the following summers.