Earth has ‘now reached 9 climate change tipping points’ as top scientists warn of ‘domino effect’ catastrophe
THE world may have already crossed nine key "tipping points" that will lead to catastrophic climate change, scientists warn.
Passing the alarming milestones means "we are in a state of planetary emergency" that could see humanity wiped from the planet.
So much damage has been done in the nine outlined areas that the effects of global warming could accelerate and create a deadly domino effect, researchers wrote in the journal .
Points of no return picked out by the team include the loss of the Amazon rainforest and the great ice sheets of Antarctica and Greenland – damage from which our planet may never recover.
"A decade ago we identified a suite of potential tipping points in the Earth system," said lead author Professor Tim Lenton, from the University of Exeter.
"Now we see evidence that over half of them have been activated."
The team, made up of top researchers from the UK, Germany, Denmark and Australia, said urgent action was needed to reduce emissions before further milestones are passed.
"The growing threat of rapid, irreversible changes means it is no longer responsible to wait and see," Professor Lenton said.
"The situation is urgent and we need an emergency response."
A tipping point is reached when certain impacts of global warming become unstoppable, such as heavy ice loss in Antarctica.
The nine active tipping points
Here are the key climate landmarks we've already crossed...
- Arctic sea ice
- Greenland ice sheet
- Boreal forests
- Permafrost
- Atlantic Meridional Overturning Circulation
- Amazon rainforest
- Warm-water corals
- West Antarctic Ice Sheet
- Parts of East Antarctica
Among the nine tipping points outlined by scientists were thawing of permafrost in Russia, large-scale die-offs of coral and a slowdown of ocean currents in the Atlantic.
Droughts in the Amazon rainforest and fires in the far north of Canada and Russia were also said to be key crossroads identified a decade ago that are now "active".
Due to the way our planet's ecosystem is connected, as each tipping point is reached, others not currently active are pushed closer to the brink.
"It is not only human pressures on Earth that continue rising to unprecedented levels," said study coauthor Professor Johan Rockström, of the Potsdam Institute in Germany.
"As science advances, we must admit that we have underestimated the risks of unleashing irreversible changes, where the planet self-amplifies global warming."
This cascade of changes sparked by global warming could threaten the existence of human civilisations, according to the researchers.
The collapse of major ice sheets on Greenland and Antarctica alone would drive sea levels up by 10 metres, turfing millions in coastal areas from their homes.
Changes to Atlantic currents have already triggered more frequent and destructive hurricanes across the western world.
Climate change explained
Here are the basic facts...
- Scientists have lots of evidence to show that the Earth’s climate is rapidly changing due to human activity
- Climate change will result in problems like global warming, greater risk of flooding, droughts and regular heatwaves
- Each of the last three decades have been hotter than the previous one and 17 of the 18 warmest years on record have happened during the 21st century
- The Earth only needs to increase by a few degrees for it to spell disaster
- The oceans are already warming, polar ice and glaciers are melting, sea levels are rising and we’re seeing more extreme weather events
- In 2015, almost all of the world's nations signed a deal called the Paris Agreement which set out ways in which they could tackle climate change and try to keep temperatures below 2C
In the past, it was thought that the planet would need to heat up by 5C for Earth's tipping points to be reached.
However, evidence shows we have already started to hit them between 1C and 2C.
Earth has heated by around 1C since pre-industrial temperatures, a figure that is certain to rise in the coming decades.
"Scientifically, this provides strong evidence for declaring a state of planetary emergency," Professor Rockström added.
"We must unleash world action that accelerates the path towards a world that can continue evolving on a stable planet."
Nearly 200 countries signed the 2015 Paris Agreement, pledging to keep global warming below 2C.
However, current national emissions pledges – even if they are met – would lead to 3C of warming.
Experts argued that further international action was needed, as it could slow the impacts of climate change, giving more time for people to adapt.
Professor Lenton added: "We might already have crossed the threshold for a cascade of inter-related tipping points.
"However, the rate at which they progress, and therefore the risk they pose, can be reduced by cutting our emissions."
His team concluded in their paper: "If damaging tipping cascades can occur and a global tipping cannot be ruled out, then this is an existential threat to civilisation."
"A saving grace is that the rate at which damage accumulates from tipping could still be under our control to some extent.
"The stability and resilience of our planet is in peril. International action – not just words – must reflect this."
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In other news, shocking photos this week revealed how Swiss glaciers have nearly disappeared since the 1800s.
Seaside towns were recently urged by experts to "move inland" as climate change meant a retreat was needed.
And, this sea level "doomsday" simulator reveals whether your home could be wiped out by rising oceans.
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