Earth nears catastrophic climate tipping points, say scientists

Climate change has pushed the world into a precarious position concerning numerous planetary 'tipping points,' according to an extensive scientific evaluation completed by over 200 researchers.

According to the authors of the Global Tipping Points report, crossing these thresholds could result in permanent alterations to vital natural systems that are essential for human well-being. They urge humanity to confront the dangers head-on and intensify efforts to avert them.

The tipping points that could be imminent include the collapse of ice sheets in Greenland and the West Antarctic, widespread thawing of permafrost, the death of coral reefs and the failure of an oceanic current in the North Atlantic, said the Guardian.

The report paints a vivid picture of potential consequences. It evaluates evidence concerning the potential triggers and probability of 26 climate tipping points – thresholds whose crossing could lead to potentially irreversible changes to Earth's system.

"Humanity faces threats of an unprecedented magnitude from these tipping points," warns Tim Lenton, a climate scientist at the University of Exeter, who led the report with support from the Bezos Earth Fund, a philanthropic organisation founded by Amazon’s Jeff Bezos.

“Tipping points in the Earth system pose threats of a magnitude never faced by humanity,” he said. “They can trigger devastating domino effects, including the loss of whole ecosystems and capacity to grow staple crops, with societal impacts including mass displacement, political instability and financial collapse.”

The report was unveiled at COP28 in Dubai as government officials conduct their first formal evaluation of progress under the landmark 2015 Paris agreement aimed at mitigating climate change.

On December 5, scientists had announced, also at COP28, that global fossil-fuel emissions for 2023 are on course to reach a record high of approximately 37bn tonnes of CO2, 1.1% more than in 2022.

Climate Action Tracker, a scientific consortium monitoring climate policies, estimated that nations' current commitments to reduce emissions, as mandated by the Paris agreement, could still result in global temperatures rising to 2.5 °C above pre-industrial levels by 2100.

The report warns that with just 1.5 °C of warming above pre-industrial levels, northern forests, mangroves and coastal ecosystems are all at risk. The Amazon rainforest may undergo significant transformation into savannah with as little as 2 °C of warming, disrupting life across South America and releasing more carbon into the atmosphere.

The consideration of tipping points underscores the need for immediate action, emphasised Manjana Milkoreit, a political scientist at the University of Oslo and a report co-author. While the Intergovernmental Panel on Climate Change has assessed various scenarios aimed at achieving the 1.5 °C target, most allow for temporary overshooting of that threshold before CO2 removal efforts later this century bring temperatures down. Such overshooting scenarios heighten the risk of tipping points that could render climate restoration impossible, said Milkoreit.

This means that humanity's decisions over the next decade or two could have repercussions lasting thousands of years, said Milkoreit. "Our current governance systems are ill-suited to a challenge of this nature."

However, for some researchers, at issue is whether highlighting tipping points brings about social and political change. "I'm sceptical," Michael Oppenheimer, a climate scientist at Princeton University told Nature.

He believes that the increasing frequency of extreme weather events and other climate impacts is more likely to sway public opinion and spur action than warnings of potential climate disasters. Moreover, if governments took adequate measures to safeguard their citizens from known climate impacts, he argues, "they wouldn't need to worry about tipping points".

The report does also offer hope by listing potential positive tipping points in social, political and economic systems that, if crossed, could yield significant benefits for the climate. Scientists point to one such tipping point already in progress as the declining cost of wind and solar power drives more investments away from fossil fuels and towards clean energy.

What is evident is that the incremental policies pursued by governments thus far fall short, said Lenton. "We must identify and trigger positive tipping points that accelerate progress along an alternative path."