Human time meets deep time

'Civilization exists by geological consent' (anonymous)

Jim Cerny

Coincident with the earthquake in Haiti, I am re-reading parts of John McPhee's collection of books on geology, Annals of the Former World. While there are many ways of reacting to the disaster, this coincidence caused me to think about the way human lifespans and civilization are completely at odds with geologic time. The full quotation in the subhead is: "Civilization exists by geological consent, subject to change without notice" (anonymous, though commonly attributed to Will Durant). Humans are wedded to our short time horizon and even for those who understand geologic time, it takes an effort to really internalize what it means and visualize how unstable our environment actually is.

Grasping geologic time scales and events.

We focus on our own lives, plus or minus about one generation. That is not only a small fraction of human history, it is less than an eye blink in the history of the planet. The 19th century was a key time for a growing appreciation of length of the earth's history, that it was not a few thousand years as some readers of the Bible had claimed. This appreciation was crucial to Charles Darwin's insights that lead to the theory of evolution. This understanding has been variously called "the abyss of time" or more often "deep time."

On a geological time scale the earth's crust is in constant, rapid movement. Human lifespans are but an instant in geologic time; even all of human history is less than an eye blink. Consider this mental exercise. Suppose we made a three-hour movie to represent the 4.5 billion-year history of the Earth. Suppose human history and agricultural settlement is 10,000 years old. That history represents a few hundredths of a second in the movie!

Let's travel to California and the 400-mile long Sierra Nevada range, which many have seen in their travels or on film. The rocks that comprise the Sierra are a complex built up over hundreds of millions of years. But starting only four million years ago a gigantic block of earth's crust began to tilt upward and has formed the Sierra. It rises steeply to 14,000 feet on the east side and then slopes more gently to the Central Valley on the west side. How many earthquakes occur in the process of that much crust rising to such an elevation?

What to do?

Given all this, it seems it is our destiny to live in a world that humans regard as stable, but which is mobile and which will inevitably bring disaster on a scale that makes the recent Haiti quake seem like a small tremor.

Haiti is at the junction of two major plates of the earth's crust that are sliding past each other, the North American Plate and the Caribbean Plate, with Haiti on the Gonave Microplate between them. Recurring earthquakes on that microplate have been recorded since at least 1615.

Even if Haiti did not have all its inter-related problems of corruption, poverty, overpopulation and environmental devastation, what are occupants of an active geologic region to do? Humans are a notoriously optimistic lot and knowledge of volcanic threats does not cause lands to be abandoned, because the short term need is too great. Romans knew that the Vesuvius volcano had erupted in the past, yet they built the towns of Pompeii and Herculaneum near it, and they were destroyed in 79 A.D. We know that Vesuvius continue to erupt, yet the area is again densely settled.

Suppose science progressed to a point where accurate predictions of volcanic eruptions and earthquakes could be made. Pinpoint stuff. Are evacuations possible? Where would millions of people go for an extended or perhaps permanent time?

Disaster as sensation.

Finally, for those humans who are not caught up in a disaster or immediately affected by it, there is a tendency to treat it as a sensation and with the 7x24 news cycle there is an enormous appetite for sensation.

In a much-anthologized 1972 science fiction story by Robert Silverberg, When We Went to See the End of the World, he tellingly satirizes the human response to disaster. The story centers around a cocktail party where people are bragging about seeing the latest thing, much as they would talk about seeing the movie Avatar right now. At this future party there is constant passing mention of ongoing human disasters, but the excitement is about a company that offers a time-travel machine, a three-hour trip that lets customers safely watch the end of the world! And each person who has made the trip reports on seeing a different disastrous end of the world. Horrible, of course, but so exciting to talk about!

February, 2010