In a new report, 160 scientists from 23 countries explain how humanity faces a “new reality” due to the “unprecedented mortality” of warm-water coral reefs – on which nearly a billion people and a quarter of all marine life depend.
With current global warming at around 1.4°C above pre-industrial levels, these reefs have now passed their thermal tipping point amid repeated mass bleaching events.
This means they will be lost on any meaningful scale unless the global temperature returns towards 1°C of warming or below, although fragments may be preserved with conservation efforts that minimise other human stressors such as overfishing and pollution.
The scientists also warn that the world is on the brink of further tipping points, including the irreversible melting of polar ice sheets, the collapse of key ocean currents and the dieback of the Amazon rainforest – where this year’s COP30 climate summit will be held.
Dr Mike Barrett, chief scientific advisor at WWF-UK and co-author of the report, said that the findings are “incredibly alarming”. “That warm-water coral reefs are passing their thermal tipping point is a tragedy for nature and the people that rely on them for food and income,” he continued.
“This grim situation must be a wake-up call that unless we act decisively now, we will also lose the Amazon rainforest, the ice sheets and vital ocean currents. In that scenario we would be looking at a truly catastrophic outcome for all humanity.”
The report’s authors say that triggering “positive tipping points” of “self-propelling change” – such as the rollout of green technologies – is the “only credible route to a safe, just and sustainable future”.
There are some reasons for optimism, with these positive tipping points having already been crossed in solar PV and wind power globally, and in the adoption of electric vehicles, battery storage and heat pumps in leading markets.
These transitions can still be accelerated, with coordinated policy action at “super-leverage points” potentially unleashing positive tipping cascades across interacting sectors such as power, transport and heating.
Once replaced, polluting technologies are unlikely to return because the new options are cheaper and better, according to the scientists, with growing global concern about climate change helping to support the transition.
Furthermore, positive tipping points are approaching in other sectors. For example, Brazil has great potential to produce green steel, green hydrogen, and green ammonia – helping to kickstart these technologies worldwide.
The scientists highlight the need to identify and trigger many more positive tipping points, and say better indicators are needed to understand tipping potential. They add that “success may depend on following a path of least polarisation”.
Professor Tim Lenton, from the Global Systems Institute at the University of Exeter, said: “There has been a radical global acceleration in some areas, including the uptake of solar power and electric vehicles. But we need to do more – and move faster – to seize positive tipping point opportunities.
“Only with a combination of decisive policy and civil society action can the world tip its trajectory from facing existential Earth system tipping point risks to seizing positive tipping point opportunities.”
Image credit: Shutterstock
Chris Seekings is the Deputy Editor of ISEP’s Transform magazine, which is published biomonthly for ISEP members. Chris’s role involves writing sustainability-related news, features and interviews, as well as helping to plan and manage the magazine’s other day-to-day activities.
