Glacial Blessings Flow

Earth's Icy Past Has Yielded Bountiful Food & Beauty

Next time you open the refrigerator and stare at the options, be grateful. Let that slight draft of cool air remind you of Earth's ice history and how that ice has formed global features that allow the planet to grow food to feed billions of people.

Ice ages have been rare in Earth's 4.56-billion-year history; ice age cycles have been even rarer. But only an ice age cycle permits the existence of a large human population capable of launching and sustaining civilization—part of which includes growing an abundant food supply.

In the past two billion years, ice ages have occurred in only three of the 21 geological periods prior to our own, and those ice ages were relatively brief. However,...