The Current Ice Age: Background information when reading After the Snow

The Current Ice Age

This article relates to After the Snow

Today's climate discussions are often so focused on global warming that it can be easy to forget that dramatic changes in climate, including extensive periods of global cooling, have been a hallmark of earth's history for billions of years. In fact, we're in an ice age right now. Currently, earth is in what's called an interglacial period (an interval of warmer temperatures that occurs between glacial periods within an ice age) of the Pliocene-Quaternary glaciation, which began approximately 2.6 million years ago, and cycles between glacial and interglacial periods roughly every 100,000 - 200,000 years.

Seventeenth century astronomer Johannes Kepler was the first to credit the earth's irregular orbit for these cyclical periods of glaciation. Today, contemporary scientists recognize that other factors, including solar output, continental positioning, and ocean circulation, may also contribute to this cyclical cooling.

A significant glaciation period began approximately 650,000 years ago, during which massive ice sheets extended from Canada across New England and the upper Midwest, as well as deep into Western Europe. This impressive ice buildup helped contribute to a drop in sea levels by 400 feet, and a 9-degree drop in average temperatures worldwide. The last ice age in human experience, often referred to simply as "The Ice Age," peaked about 20,000 years ago, and while we may currently be focused on the warming of the planet, many scientists agree that we're still in a general cooling cycle, in relation to the history of the phenomenon. S.D. Crockett's novel imagines, in particularly vivid fashion, exactly how a real glacial ice age might affect human culture in the twenty-first century: a possibility that many of these scientists apparently do not see as all that far-fetched.


Image: The Baltoro Glacier in Kashmir, Northern Pakistan. At 62 kilometres it is one of the longest alpine glaciers on earth. Photo by Guilhem Vellut

Filed under People, Eras & Events

This "beyond the book article" relates to After the Snow. It originally ran in April 2012 and has been updated for the September 2013 paperback edition. Go to magazine.