Earth is on the verge of catastrophic climate tipping points, crossing which humanity would face an existential threat of a magnitude “never before faced”, a report compiled by over 200 scientists warned.
Tipping points are small changes that can bring about drastic effects, and researchers warn of five such changes with the potential to cause abrupt and irreversible impacts on the planet.
The tipping points flagged in the report include imminent changes to the Greenland and West Antarctic ice sheets, coral reef die-offs due to warming oceans, water circulation changes in the North Atlantic, as well as melting in permafrost regions.
The five tipping points are imminently at risk of being crossed due to current levels of global warming with three more under threat in the 2030s as the world exceeds 1.5°C global warming, scientists say.
These tipping points pose a threat of “magnitude never before faced by humanity,” they warn, adding that “the world is on a disastrous trajectory”.
The most immediate dangers, scientists say, are to coral reefs across the world threatened by current levels of ocean warming as well as the melting of ice caps in Greenland and Antarctica that could raise sea levels globally.
Researchers also cautioned that with just 2°C of warming above pre-industrial levels, the Amazon rainforest could be replaced by a savannah-type ecosystem, leading to more carbon being pumped into the atmosphere.
The collapse of the Atlantic Ocean’s circulation system along with global warming can cause half of the global area for growing wheat and maize to be lost, scientists warn.
Even crossing one of the dangerous tipping points could trigger others, “causing a domino effect” of accelerating an unmanageable change to the planet’s life-support systems, they said.
Researchers call for rapid transformation of societies across the globe to reduce carbon emissions such as exponential increases in renewable electricity, the global reach of environmental justice movements, and the accelerating rollout of electric vehicles.
While the Intergovernmental Panel on Climate Change has offered different scenarios to curtail global temperatures to within 1.5°C above pre-industrial levels, almost all of these appear to overshoot that level briefly before dropping later this century.
This indicates at least some of the tipping points may be breached, leading to irreversible climate effects.
“This means that societies must urgently be made more resilient to minimise the vast and unequal harms,” the report noted.
“Critically, more resilient societies are also needed to ensure that collective focus on triggering positive tipping point opportunities can be sustained even through a negative tipping event,” scientists said.
To curb the effects of these catastrophic tipping points, researchers say fossil fuel emissions should be phased out worldwide before 2050.
Scientists also call on the UN secretary-general to convene a global summit to formalise the agenda to manage these tipping points.
“As a matter of urgency, tipping point threats should also feature on the agenda of key international fora, including the 2024 meeting of the G20 in Brazil,” they say.