Deep Time

Painting of a pre-historic animal on a cave wall

What is deep time?

Deep time and its interference with human time are key issues in the Anthropocene. What is deep time? And how do we interfere with it today in ways that are characteristic of the Anthropocene? In the history of science, deep time is a relatively recent discovery. Generally, what we mean by deep time is geological time or cosmic time, in other words: billions of years. Astronomers estimate that the big bang happened about 13.8 billion years ago and the earth to have formed 4.54 billion years ago. This is real deep time. In contrast, according to traditional Christian world views, for example, God created the world — and the plants, animals and humans on it — no more than a few thousand years ago.

There are still religious fundamentalists holding this belief today. 19th- and 20th-century scientific cosmology and geology overturned such views. Modern science has historicized “nature.” It all started with Earth history. With the ice ages that preceded the warming of the Holocene, scientists in the 19th century began to recognize that the earth’s climate had changed many times, and quite dramatically, since the planet had formed in our solar system. The theory of evolution introduced by Charles Darwin meant that life on Earth also has a history. Plant and animal species are not unchangeable forever. Rather, most of the plants and animals that have been around on Earth in the past have died out or evolved into something different. Deep time is key to understanding such evolutionary and geological processes. Their time is different from the processes we experience in human society. The latter operate on an entirely different timescale. For example, the average human life expectancy is still below a hundred years. The cultural memory of oral traditions extends two to three generations (though some elements of such a tradition may go significantly deeper than that).

Cultures based on writing generally create longer traditions. Think of Judaic, Christian, Islamic and Buddhist religious traditions which go back a few thousand of years. However, this is still a long way from geological timescales. So, what does it mean to state that human time interferes with geological time in the Anthropocene? We are only beginning to explore this question. What seems clear enough though is that, as humanity has become a geophysical force in the Anthropocene (Anthropos), the changes are beginning to show on the huge scales of geological deep time. For example, according to some recent model calculations, anthropogenic climate change has already delayed the next ice age by at least 100,000 years. In other words, our emissions of greenhouse gases in the last 150 years — which equals five generations — are causing an effect we can expect to last 3333 generations, or roughly half the time our species (homo sapiens) has been around on Earth.

Franz Mauelshagen

 

Researchers: Erich Draganits, Michael Jursa, Christian Köberl, Michael Wagreich