‘Collapse of civilisation is the most likely outcome’: top climate scientists

Australia’s top climate scientist says “we are already deep into the trajectory towards collapse” of civilisation, which may now be inevitable because 9 of the 15 known global climate tipping points that regulate the state of the planet have been activated.

Australian National University emeritus professor Will Steffen (pictured) told Voice of Actionthat there was already a chance we have triggered a “global tipping cascade” that would take us to a less habitable “Hothouse Earth” climate, regardless of whether we reduced emissions.

Steffen says it would take 30 years at best (more likely 40-60 years) to transition to net zero emissions, but when it comes to tipping points such as Arctic sea ice we could have already run out of time. 

Evidence shows we will also lose control of the tipping points for the Amazon rainforest, the West Antarctic ice sheet, and the Greenland ice sheet in much less time than it’s going to take us to get to net zero emissions, Steffen says.

“Given the momentum in both the Earth and human systems, and the growing difference between the ‘reaction time’ needed to steer humanity towards a more sustainable future, and the ‘intervention time’ left to avert a range of catastrophes in both the physical climate system (e.g., melting of Arctic sea ice) and the biosphere (e.g., loss of the Great Barrier Reef), we are already deep into the trajectory towards collapse,” said Steffen.

“That is, the intervention time we have left has, in many cases, shrunk to levels that are shorter than the time it would take to transition to a more sustainable system.

“The fact that many of the features of the Earth System that are being damaged or lost constitute ‘tipping points’ that could well link to form a ‘tipping cascade’ raises the ultimate question: Have we already lost control of the system? Is collapse now inevitable?”

This is not a unique view – leading Stanford University biologists, who were first to reveal that we are already experiencing the sixth mass extinction on Earth, released new research this weekshowing species extinctions are accelerating in an unprecedented manner, which may be a tipping point for the collapse of human civilisation.

Also in the past week research emerged showing the world’s major food baskets will experience more extreme droughts than previously forecast, with southern Australia among the worst hit globally.

Steffen used the metaphor of the Titanic in one of his recent talks to describe how we may cross tipping points faster than the time it would take us to react to get our impact on the climate under control.

“If the Titanic realises that it’s in trouble and it has about 5km that it needs to slow and steer the ship, but it’s only 3km away from the iceberg, it’s already doomed,” he said.

‘This is an existential threat to civilization’

Steffen, along with some of the world’s most eminent climate scientists, laid out our predicament in the starkest possible terms in a piece for the journal Nature at the end of last year.

They found that 9 of the 15 known Earth tipping elements that regulate the state of the planet had been activated, and there was now scientific support for declaring a state of planetary emergency. These tipping points can trigger abrupt carbon release back into the atmosphere, such as the release of carbon dioxide and methane caused by the irreversible thawing of the Arctic permafrost.

“If damaging tipping cascades can occur and a global tipping point cannot be ruled out, then this is an existential threat to civilization,” they wrote.

“No amount of economic cost–benefit analysis is going to help us. We need to change our approach to the climate problem.

“The evidence from tipping points alone suggests that we are in a state of planetary emergency: both the risk and urgency of the situation are acute.”

Steffen is also the lead author of the heavily cited 2018 paper, Trajectories of the Earth System in the Anthropocene, where he found that “even if the Paris Accord target of a 1.5°C to 2°C rise in temperature is met, we cannot exclude the risk that a cascade of feedbacks could push the Earth System irreversibly onto a ‘Hothouse Earth’ pathway.”

Steffen is a global authority on the subject of tipping points, which are prone to sudden shifts if they get pushed hard enough by a changing climate, and could take the trajectory of the system out of human control. Further warming would become self-sustaining due to system feedbacks and their mutual interaction.

Steffen describes it like a row of dominos and his concern is we are already at the point of no return, knocking over the first couple of dominos which could lead to a cascade knocking over the whole row.

“Some of these we think are vulnerable in the temperature range we’re entering into now,” said Steffen.

“If we get those starting to tip we could get the whole row of dominos tipping and take us to a much hotter climate even if we get our emissions down.”

Even the notoriously conservative United Nations Intergovernmental Panel on Climate Change (IPCC) has found that already with the 1.1°C of warming we have had to date, there was a moderate risk of tipping some of these – and the risk increased as the temperatures increased.

Steffen believes we are committed to at least a 1.5°C temperature rise given the momentum in the economic and climate system, but we still have a shot at staying under 2°C with urgent action.

+4°C world would support < 1 billion people

Professor Hans Joachim Schellnhuber, director emeritus and founder of the Potsdam Institute for Climate Impact Research, believes if we go much above 2°C we will quickly get to 4°C anyway because of the tipping points and feedbacks, which would spell the end of human civilisation.

There is a very big risk that we will just end our civilisation”: Professor Schellnhuber

Johan Rockström, the head of one of Europe’s leading research institutes, warned in 2019 that in a 4°C-warmer world it would be “difficult to see how we could accommodate a billion people or even half of that … There will be a rich minority of people who survive with modern lifestyles, no doubt, but it will be a turbulent, conflict-ridden world”.

Schellnhuber, one of the world’s leading authorities on climate change, said that if we continue down the present path “there is a very big risk that we will just end our civilisation. The human species will survive somehow but we will destroy almost everything we have built up over the last two thousand years.”

Schellnhuber said in a recent interview that the IPCC report stating we could stay below 1.5°C of warming was “slightly dishonest” because it relies on immense negative emissions (pulling CO2 out of the air) which was not viable at global scale. He said 1.5°C was no longer achievable but it was still possible to stay under 2°C with massive changes to society.

If we don’t bend the emissions curve down substantially before 2030 then keeping temperatures under 2°C becomes unavoidable. The “carbon law” published in the journal Science in 2017 found that, to hold warming below 2°C, emissions would need to be cut in half between 2020 and 2030.

Steffen told Voice of Action that the three main challenges to humanity – climate change, the degradation of the biosphere and the growing inequalities between and among countries – were “just different facets of the same fundamental problem”.

This problem was the “neoliberal economic system” that spread across the world through globalisation, underpinning “high production high consumption lifestyles” and a “religion built not around eternal life but around eternal growth”.

“It is becoming abundantly clear that (i) this system is incompatible with a well-functioning Earth System at the planetary level; (ii) this system is eroding human- and societal-well being, even in the wealthiest countries, and (iii) collapse is the most likely outcome of the present trajectory of the current system, as prophetically modelled in 1972 in the Limits to Growth work,” Steffen told Voice of Action.

Eternal growth is not possible

The Limits to Growth model released by the Club of Rome in 1972 looked at the interplay between food production, industry, population, non-renewable resources and pollution.

The basic findings were that you can’t grow the system indefinitely as you will cause environmental and resource issues that will ultimately cause the whole global system to collapse (ABC’s This Day Tonight program covered it here). At the time of the model’s release it accurately reproduced the historical data from 1900 to 1970.

2008 study by Graham Turner, then a senior CSIRO research scientist, used three decades of real-world historical data to conclude that the Limits to Growth model’s predictions were coming to pass: “30 years of historical data compare favourably with key features of a business-as-usual [BAU] scenario called the ‘standard run’ scenario, which results in collapse of the global system midway through the 21st century.”

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