It may sound more like a conspiracy theory than a subject for a scientific inquiry but scientists have posed a fascinating question about the timeline of Earth’s inhabitants: was another industrial civilisation on Earth before humans?
In a new study, a climatologist and a professor of astrophysics teamed up to explore whether an extinct pre-human species could have caused global warming 56 million years ago.
Geological records reveal a period of dramatic change buried deep in the planet’s history – the Paleocene-Eocene Thermal Maximum (PETM).
While there is little question about whether this spike was the result of natural forces – the researchers assert it was ‘almost certainly not’ caused by an ancient intelligent civilisation – the study provides new insight on the impact our own society could leave on the planet millions of years down the line.
To investigate this idea, the pair set out to discover what kind of evidence could conceivably still exist to demonstrate this event was caused by a pre-human industrial society.
It may sound more like a conspiracy theory than a subject for scientific inquiry but scientists are seriously investigating whether there was another industrial civilisation on Earth before humans (stock image)
In doing so, the pair considered what evidence from our own culture would be left behind for future civilisations to uncover after the passage of aeons.
Their thinking could have widespread implications for our understanding of how best to look for alien life on other planets.
Professor Adam Frank, of the University of Rochester reports their findings in an in-depth article for The Atlantic.
The astronomer’s initial interest in the subject was sparked after a conversation with fellow physicist Gavin Schmidt, director of Nasa’s Goddard Institute for Space Studies (GISS) in New York.
Professor Frank was hoping to solve the question of whether any industrial civilisation that rises on any planet in the universe will trigger a shift in their homeworld’s climate.
Upon hearing about his research, Dr Schmidt questioned his assumption that humanity is the only time a civilisation has arisen that is capable of affecting the Earth’s climate.
Writing in The Atlantic, Professor Frank said: ‘There is a conundrum here. If an earlier species’s industrial activity is short-lived, we might not be able to easily see it.
In a new study, a climatologist and a professor of astrophysics teamed up to explore the far-fetched idea. They examined the notion that a period of global warming 56 million years ago may well have been made (stock image)
‘The PETM’s spikes mostly show us the Earth’s timescales for responding to whatever caused it, not necessarily the timescale of the cause.
‘So it might take both dedicated and novel detection methods to find evidence of a truly short-lived event in ancient sediments. In other words, if you’re not explicitly looking for it, you might not see it.’
Evidence of ancient industrial civilisations might include the presence of plastics in the ocean, as well as fossil fuel use and the distribution of fertiliser in agriculture.
Fossils and other remains are likely to have blown away with the sands of time.
While they were unable to establish the presence of any such proof, their thought experiment lead to some interesting ideas – particularly when it comes to other planets.
It suggests the possibility of a string of alien cultures on a single planet which are literally fuelled by the bodies of the predecessors.
Evidence of ancient industrial civilisation might include the presence of plastics in the ocean, as well as fossil fuel use and the distribution of fertiliser in agriculture. Fossils and other bodily remains are likely to have blown away with the sands of time (stock image)
Professor Frank proposes that civilisations might in their collapse trigger the conditions needed for oil, gas and other natural reserves to be built up.
Future civilisations could then use these to build up to their own industrial periods, before collapsing and starting the cycle again.
He added: ‘Our work also opened up the speculative possibility that some planets might have fossil-fuel-driven cycles of civilization building and collapse.
‘If a civilization uses fossil fuels, the climate change they trigger can lead to a large decrease in ocean oxygen levels.
‘These low oxygen levels (called ocean anoxia) help trigger the conditions needed for making fossil fuels like oil and coal in the first place. In this way, a civilization and its demise might sow the seed for new civilizations in the future.’
The full findings of the study were published in the International Journal of Astrobiolog.
WHEN WAS THE PALEOCENE AND HOW DID IT IMPACT BRITAIN’S CLIMATE?
The Paleoscene (‘old recent’) is a geological period that stretched from 66 to 56 million years ago.
During this period, the Earth’s climate was up to 15°C (27°F) warmer than it is today.
As a result, tropical and sub tropical forests extended further north and would have been widespread in the UK.
At the time there had not been an ice age for 100 million years.
The distance between Europe and Greenland was a tenth of what it is today.
There was massive volcanic activity between Baffin Island and northwest Europe that extended as far south as Bristol Channel.
The shape of the continents were similar to those today except they were arranged differently due to tectonic plates. Britain, Ireland and Norway were all landlocked and the Arctic sea was almost completely surrounded by land
Britain, Ireland and Norway were all landlocked and the Arctic sea was almost completely surrounded by land.
The shape of the continents were similar to those today except they were arranged differently due to tectonic plates, according to a website dedicated to the Paleocene.
Most of the world’s most famous geological features would not have been recognisable, including mountain ranges like the Alps and Himalayas which formed during the Tertiary period.
Prior to the Paleocene-Eocene Thermal Maximum (PETM) – which occurred around 55 million years ago – non-avian dinosaurs had been extinct for around ten million years.
Early mammals, amphibians, reptiles, insects and flowering plants were the dominant forms of life.
Mammals were generally small, had short legs and five toes on each foot.