Scientists investigate whether another civilisation lived on Earth before humans

SCIENTISTS believe a global warming event that took place 56 million years ago could help us determine the fate of any civilisations that lived on Earth before us.

SCIENTISTS are searching for signs of an extinct civilisation that pre-dates humankind.

What sounds like a wild conspiracy theory could hold the key to finding alien life and help us measure our impact on our planet, they say.

The new study hinges on a warming period 56 million years ago when global temperatures were around 8C higher than today — what’s known as the Palaeocene-Eocene Thermal Maximum (PETM).

As a guide for what we might expect from ancient inhabitants, the authors looked at what our own civilisation may leave behind on Earth as signs of our existence — such as plastics in the ocean, evidence of fertiliser use, and (above all) evidence of fossil fuel use.

But don’t go expecting to stumble upon any massive structures, they claim, because there’s no way they would have remained preserved through tens of millions of years of geological activity.

There is no evidence to suggest there was a pre-human civilisation on Earth. Picture: Lyndon Mechielsen

“There is a conundrum here. If an earlier species’ industrial activity is short-lived, we might not be able to easily see it,” Professor Adam Frank of the University of Rochester writes in The Atlantic.

“The PETM’s spikes mostly show us the Earth’s timescales for responding to whatever caused it, not necessarily the timescale of the cause.

“In other words, if you’re not explicitly looking for it, you might not see it.”

The scientists concluded that there is no evidence of an earlier civilisation on Earth — but their ideas could extend to the search for alien life on other planets.

In this way, the new paper relates its theory for precursors to human civilisation to the Drake equation — a probabilistic approach to estimating the amount of intelligent extraterrestrial life in the Milky Way — developed by astronomer Frank Drake.

One of the equation’s key variables is the length of time such an alien race can broadcast detectable signals across the galaxy for others to pick up.

A possible reason why we haven’t achieved contact with an alien species is that this “length of time” may be extremely short.

Take humans as an example — we’ve been kicking about for around 12,000 years but have only been able to send radio signals into space for about a century.

But it could also indicate that a technologically advanced alien race capable of broadcasting its existence has a very short life span.

And our wasteful society has a lot to learn from that foreboding equation, claims the study’s co-author Gavin Schmidt, director of Nasa’s Goddard Institute for Space Studies.

A key variable is whether an alien race could broadcast detectable signals across the galaxy.

“It might be the detectable period of a civilisation is much shorter than its actual longevity, because you can’t last a long time doing the kinds of stuff that we’ve been doing,” Dr Schmidt told Motherboard.

“You either stop, because you’ve messed it all up, or you learn not to do it. Either way, the burst of activity, wastefulness and massive footprints is actually a very short amount of time.

“Maybe it’s happened a billion times in the universe,” he said, “but if it only lasted 200 years every time, then you’d never see it.”

This story originally appeared on The Sun and was republished with permission.