The Limited Lifespan of Technological Civilizations

A recent paper in the Cambridge Journal of Astrobiology concludes that the typical
technological species becomes extinct within 500 years after attaining modern technology and that this extinction leaves the civilization's planet uninhabitable.

There is some cool information here for both my science fiction writers out there, but also for people concerned about climate change.

The paper, by retired astrophysicist and mathematics professor Daniel Whitmire, of the University of Arkansas, makes the following arguments:

1. Based on the "Principle of Mediocrity," a cornerstone of modern cosmology, when there is only one data point, we need to assume that the data is typical of other examples, even though we cannot detect them. So, in the absence of evidence to the contrary, we should believe that humans are typical of other intelligent, technological species out there in the universe. Statistically, this means we are toward the middle of the bell-shaped curve, where the vertical line is in the middle of the graphic.

2.  So...assuming we really are typical, we only know two fundamental things, a) that we are the first technological species to evolve on the Earth and b) we are early in our technological evolution.

No archaeological evidence of a previous technological civilization has been found, (Erich von Däniken doesn't count) and a true technological civilization would leave evidence that could be found for millions of years.

3.  The evolution of technological species IS statistically probable, Whitmire says, because our typical technological civilization evolved in the first 22% of the projected total lifetime of the part of Earth's biosphere suitable for land animals.  If a technological species were to be improbable, then we would expect to have evolved toward the end of Earth's biosphere lifetime, i.e beating the odds.

4.  If technological species go extinct while leaving the biosphere viable, then later technological species are likely to evolve, Whitmire says. On the other hand, if extinction leaves the land biosphere uninhabitable, the reset time could easily take too long for evolution of another technological species, he contends.

5.  Given the principle of mediocrity, which says that humans are typical of other existing technological species, and because we are early in our technological evolution, the statical likelihood is that other existing technological species we encounter will also be in the relatively early stages of technology development, and be the first to evolve on their planet.

6.  When you calculate the bell-shaped curves of probability, the best we can say, based on current evidence, is that a technological civilization is "likely" to last 500 years or less, says the author.

• If our technological civilization survives another 1,000 years, then statistically the "likely" survival range would jump to 5,000 years or less.
• Note that we are already 100 years into our own technological civilization.

7.  Therefore, the best evidence we have, based on the statistical principle of mediocrity, is that the typical technological species has a short lifetime and that their extinction typically coincides with the extinction of their planetary biosphere.

Note: A technological species in defined by the author as those biological species that have developed the ability to affect the global environment and utilize electronic devices. That means that one of the signature characteristics defining a technological species is invention of radio!

I said that this blog post is for my science fiction writers out there, because I think that there is some cool basis for speculative writing here.  I would also caution that it is always POSSIBLY for a civilization to be an outlier, but the ODDS say that both we, and any aliens we encounter, will be toward the center of the curve, and thus similar to ourselves.

When it comes to climate change, this logic can also serve as a basis for what we know, based on statistics, about civilizations faced with climate change and other extinction-level events. Based on the very limited statistical information we have (one data point), the likelihood is that in 400 years or less, we will make OUR planet uninhabitable.

All of this speculation is based on statistics. It is not a prediction of real world events. But it matches pretty well with the existential threats of nuclear war and climate change that our society faces. It would be nice to prove that we are NOT typical, as current defined, because we beat the odds.

This blog post was inspired by this article, but I went to the original published journal article to write my summary.