Radical
The AMOC’s collapse would plunge north-western Europe into a “little ice age,” the scientists said.
They described how winter sea ice would cover the North Sea, temperatures could dip to as low as minus 30C in Edinburgh and London would experience three frozen months a year, contrasting with extreme heatwaves in summer.
Breaching these tipping points will have a catastrophic impact on billions of people across the world who rely on their ecosystems for food and livelihoods, cause extreme damage to biodiversity, decrease agricultural yields in much of the world and lead to incalculable costs to local and national economies.
To prevent this, countries must limit the extent to which warming overshoots 1.5C in the next few years, the report said, adding that every degree and year spent above this threshold matters.
Prof Lenton, from the Global Systems Institute at the University of Exeter, said: “In the two years since the first Global Tipping Points Report, there has been a radical global acceleration in some areas, including the uptake of solar power and electric vehicles.
Damage
“But we need to do more – and move faster – to seize positive tipping point opportunities.
“By doing so, we can drastically cut greenhouse gas emissions and tip the world away from catastrophic tipping points and towards a thriving, sustainable future.”
The report also warned that current policies and decision-making processes do not take tipping points into account and will not address the scale of the abrupt and irreversible impacts that come when they are breached.
Beyond action to cut emissions and remove carbon from the atmosphere, the experts said that the impacts caused by tipping processes must also be considered in risk assessments, adaptation policies, loss and damage mechanisms and human rights litigation.
Gravity
Dr Manjana Milkoreit, from the University of Oslo, said: “Tipping points present distinct governance challenges compared to other aspects of climate change or environmental decline, requiring both governance innovations and reforms of existing institutions.”
The report comes as ministers meet on Monday in Brazil for discussions before the UN climate conference, Cop30, which is being held in the Amazonian city of Belem next month.
Dr Mike Barrett, chief scientific adviser at WWF-UK and co-author of the report, said: “As we head into the Cop30 climate negotiations it’s vital that all parties grasp the gravity of the situation and the extent of what we all stand to lose if the climate and nature crises are not addressed.
“The solutions are within our reach. Countries must show the political bravery and leadership to work together and achieve them.”
This Author
Rebecca Speare-Cole is the PA sustainability reporter.