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Are we heading for extinction? Maths models reveal the three possible fates for our planet

Scientists have modelled the three possible fates for our planet as Earth’s population grows and the effects of climate change worsen.

Mathematicians modelled how advanced civilisations on ancient exoplanets might have survived or perished when faced with a similar changing environment.

They showed that humanity could go through a soft landing, a gradual die off, or full blown collapse.

Experts said a die-off, in which as much as seven in ten of a planet’s inhabitants were wiped out before stabilising, was by far the most common outcome.

A soft landing was the most positive outcome, and occurred when a civilisation adapted to its changing planet without a mass extinction.

During a full blown collapse, the planet was too sensitive to recover from damage caused by its inhabitants, leading to a rapid annihilation of all intelligent life.

There’s bad news for Earth. Even when planets switched to renewable fuels to save themselves from extinction, the damage done was sometimes still enough to wipe out the inhabitants, according to the models.

Scientists said the simulations show that if you ‘push a planet too hard’ before changing how you treat it, it ‘won’t return to where it began’.

This graph shows a modelled population (x-axis) in balance with its use of resources, which directly affects the planetary environment (y-axis). The red dots show where the civilisation is stable with its environment. Outside of this damage is done to one or the other

The team, led by scientists at the University of Rochester in New York, used models for population growth on Earth to mark out how alien planets may have grown.

Using statistical models they mapped out possible histories of alien worlds, the civilisations they grow, and the climate change that follows.

They called these societies ‘Exo-civilizations’ and say that learning from their mistakes could help us prepare for the effects of climate change.

Writing in the Atlantic, coauthor Professor Adam Frank said: ‘Given that more than 10 billion trillion planets likely exist in the cosmos, unless nature is perversely biased against civilisations like ours, we’re not the first one to appear.

‘That means each exo-civilization that evolved from its planet’s biosphere had a history: A story of emergence, rising capacities, and then maybe a slow fade or rapid collapse.

‘And just as most species that have ever lived on Earth are now extinct, so too most civilizations that emerged (if they emerged) may have long since ended.

This image shows a modelled population in which it uses its resources poorly leading to a highly unstable environment. As conditions on the planet collapse, the civilisations in these scenarios are quickly wiped out leading to a 'full-blown' collapse

This image shows a modelled population in which it uses its resources poorly leading to a highly unstable environment. As conditions on the planet collapse, the civilisations in these scenarios are quickly wiped out leading to a ‘full-blown’ collapse

WHAT DO SCIENTISTS THINK ARE THE THREE POSSIBLE FATES FOR OUR PLANET?

To find out the possible fate for humanity, scientists have created a series of advanced computer models to simulate the interactions between energy-intensive civilisations – like ours – and their planets.

Scientists ran a series of simulations to find how these civilisations fared. 

Unfortunately, of the three fates observed, none were positive.

University of Rochester Professor of Physics and Astronomy Alan Frank, who co-authored the study, said the simulations revealed ‘a radical truth about the challenge we face as we push the Earth into its human-dominated era.’

Outcome 1: The Die Off

This was by far the most common outcome observed by researchers. 

As the civilisation on the simulated planet used energy, its population grew.

However, as the civilisation continued to burn through its resources, it pushed the planet away from the conditions the population had been accustomed to.

Civilian numbers continued to grow, spiraling past the planet’s limit.

These worlds would then suffer a devastating drop in the number of people until a sustainable planetary civilisation was achieved once more. 

In many of the models, researchers observed as much as 70 per cent of the population perish before a steady state was reached again.  

Outcome 2: The Soft Landing 

This was the most positive outcome of the three observed outcomes.

As before, the civilisation on the Earth-like planet used its resources and started to expand in numbers.

But this time, the growing population and the planet maintained a smooth transition to a new, balanced equilibrium.

Although the civilisation changed the planet, it did so without triggering a mass extinction, like those observed in the first outcome.

Outcome 3: Full-Blown Collapse

Like the simulations that ended in mass extinction, in this final outcome observed in the computer models, population number skyrocketed.

However, these worlds were too sensitive to change and were unable to cope with a rapidly expanding, resource-hungry civilisation.

The planets soon deteriorated, ‘like a houseplant that withers when it’s moved,’ Dr Frank explains.

As conditions on the planet collapsed, the civilisations in these scenarios were quickly wiped out.

Researchers programmed the civilisations to switch from high-impact energy sources to low-impact ones, to find out whether this would change their fate.

Populations that relied solely on high-impact resources were immediately wiped-out, while those that made the switch to low-impact alternatives would fall, then stabilise. Albeit temporarily.

Unfortunately, it was never enough to delay the inevitable, with the simulated civilisation always eventually rushing downward to extinction.

‘So we’re exploring what may have happened to others to gain insights into what might happen to us.’

The team’s calculations combined population statistics from Earth’s species with generic physics and chemistry that make up climates on other planets.

They applied the laws of these climates to a scenario in which an industrial civilisation arrived on a planet and began consuming its resources.

As the society consumed resources for energy, it grew because its capacity to feed more people expanded, allowing it to use up more resources.

Eventually this loop has feedback effects on the planet that damage it and begin to make it uninhabitable.

This mirrors humanity’s relationship with Earth following the industrial revolution, during which we began to burn fossil fuels for energy, Professor Frank said. 

As part of the simulations, researchers imagined the civilisation had two types of energy source: One with a high impact on the planet, like fossil fuels, and one with a low impact, like solar power.

In some of the models the researchers allowed the civilisation to switch to low-impact resources as the health of the planet plummeted.

The models revealed three distinct types of civilisational histories that reveal what could happen on Earth if population and climate trends continue.

Unfortunately, of the three fates observed, none were positive.

The most common outcome observed by the team was known as ‘the Die Off’. 

As the civilisation on the simulated planets used energy, its population exploded, but its use of resources pushed the planet away from the conditions the society had become accustomed to.

During a full blown collapse, the planet was too sensitive to recover from damage caused by its inhabitants, leading to a rapid annihilation of all intelligent life (stock image)

During a full blown collapse, the planet was too sensitive to recover from damage caused by its inhabitants, leading to a rapid annihilation of all intelligent life (stock image)

As the population continued to expand the planet became uninhabitable, forcing a devastating drop in the number of civilians until a sustainable planetary civilisation was achieved once more.

In many of the models, researchers observed that as many as 70 per cent of the population perished before a steady state was reached again.

The second outcome viewed by the team was the soft landing – the most positive outcome of the three observed.  

This time, the growing population and the planet maintained a smooth transition to a new, balanced equilibrium, partly through low-impact resources.

Although the civilisation changed the planet, it did so without triggering a mass extinction, like those observed in the first outcome.

Outcome number three was a full-blown collapse, which also started with a skyrocketing population. 

However, these worlds were too sensitive to change and were unable to cope with a rapidly expanding, resource-hungry civilisation. 

As conditions on the worlds collapsed around them, the civilisations in these scenarios were rapidly wiped out.

Even when planets switched to renewable fuels to save themselves from extinction, the damage done was sometimes still enough to wipe out the inhabitants (stock image)

Even when planets switched to renewable fuels to save themselves from extinction, the damage done was sometimes still enough to wipe out the inhabitants (stock image)

Researchers programmed the civilisations to switch from high-impact energy sources to low-impact ones, to find out whether this would change their fate.

While populations that relied solely on high-impact resources were immediately wiped-out, those that made the switch to low-impact alternatives would fall, then stabilise.

Unfortunately, it was not always enough to stop an extinction event, with some simulated civilisation still rushing downward to extinction eventually.

Professor Frank said the models showed that switching to renewable sources may not help Earth if humanity irreparably damages it before shifting to green energy.

He said: ‘The collapses that occurred even when the civilisation did the smart thing demonstrated an essential point about the modelling process.

‘Because the equations capture some of the real world’s complexity, they can surprise you.

‘In some of the “delayed collapse” histories, the planet’s own internal machinery was the culprit. Push a planet too hard, and it won’t return to where it began.’



Read more at DailyMail.co.uk


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