- Widespread mortality of warm-water coral reefs under way, as world reaches first tipping point
- With global warming set to breach 1.5°C, world dangerously close to further catastrophic tipping points
- These include melting ice sheets, Amazon rainforest dieback and collapse of vital ocean currents
- Tipping points pose a new type of threat that current international structures and agreements are not designed to counter
- Key to averting catastrophe is to act urgently, by supporting societal transformation and triggering 'positive tipping points' such as the self-propelling rollout of green technologies
The world faces a "new reality" as we have reached the first of many Earth system tipping points that will cause catastrophic harm unless humanity takes urgent action, according to a landmark report released today (13 Oct) by the University of Exeter and international partners.
With ministers gathering today ahead of the COP30 summit, the second Global Tipping Points Report finds that warm-water coral reefs - on which nearly a billion people and a quarter of all marine life depend - are passing their tipping point. Widespread dieback is taking place and - unless global warming is reversed - extensive reefs as we know them will be lost, although small refuges may survive and must be protected.
We are on the brink of more tipping points, with devastating risks for people and nature: the irreversible melting of polar ice sheets, the collapse of key ocean currents and the dieback of the Amazon rainforest - where COP30 will be held.
With global warming set to breach 1.5°C, the report - by 160 scientists at 87 institutions in 23 countries - argues that countries must minimise temperature overshoot to avoid crossing more tipping points. Every fraction of a degree and every year spent above 1.5°C matters.
Action to trigger "positive tipping points" of self-propelling change - such as the rollout of green technologies - now offers the only credible route to a safe, just and sustainable future, the report says.
The researchers are working with Brazil's COP30 Presidency to ensure that tipping points are on the agenda at the summit.
Professor Tim Lenton, from the Global Systems Institute at the University of Exeter, said: "We are rapidly approaching multiple Earth system tipping points that could transform our world, with devastating consequences for people and nature. This demands immediate, unprecedented action from leaders at COP30 and policymakers worldwide.
"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. 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."
Dr Mike Barrett, chief scientific advisor at WWF-UK and co-author of the report, said: "The findings of this report 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. 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.
"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."
The report says that the nature of abrupt and irreversible Earth system tipping points mean that they pose a different type of threat to other environmental challenges, and that current policies and decision-making processes are not adequate to respond. Global action must include accelerating emissions reductions and scaling up carbon removal to minimise temperature overshoot. The expected impacts of tipping processes need to be considered in risk assessments, adaptation policies, loss and damage mechanisms and human rights litigation.
Dr Manjana Milkoreit, from the University of Oslo, said: "Current policy thinking doesn't usually take tipping points into account. 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.
"Preventing tipping points requires 'frontloaded' mitigation pathways that minimise peak global temperature, the duration of the overshoot period above 1.5°C, and the return time below 1.5°C. Sustainable carbon dioxide removal approaches need to be rapidly scaled up to achieve this."
The report's authors are working with Brazil's COP30 Presidency on the "Action Agenda" as a platform for accelerating climate transition plans and triggering self-reinforcing change across different sectors - from agriculture to energy, from forests to cities - towards low-carbon and climate-resilient global transformation.
The President Designate of COP30 in Brazil, Ambassador André Corrêa do Lago, said: "As part of a global mobilisation against climate change - our 'Global Mutirão' - the COP30 Presidency invited community leaders, scholars and scientists to explore the best available science and ancestral wisdom around how our institutions can gain exponentiality in deploying solutions and versatility in responding to the climate crisis, including through agile, iterative and adaptive capabilities. I welcome the Global Tipping Points Report as a positive and timely response to our invitation. The report stands as hopeful and sober evidence that humanity can still choose to change and evolve towards a safe, prosperous and equitable future."
The report highlights progress on positive tipping points - and opportunities for a cascade of positive change:
- Positive tipping points have 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. Coordinated policy action at "super-leverage points" can unleash positive tipping cascades across interacting sectors (e.g. power, transport and heating), bringing forward tipping in all. Once replaced, polluting technologies are unlikely to return because the new options are cheaper and better. Social attitudes are also tipping. Concern about climate change is growing globally - and even small numbers of people can tip the majority.
- More positive tipping points are approaching in sectors including goods transport. COP30's host nation, Brazil, has great potential for producing green steel, green hydrogen, and green ammonia - helping to kickstart these crucial technologies worldwide. Positive tipping points can rapidly restore nature and biodiversity. Ecosystem restoration can tip degraded systems back to health, and shifts to more sustainable patterns of consumption and production can lead to tipping points in food and fibre supply chains that end deforestation and ecosystem conversion.
- We need to identify and trigger many more positive tipping points. Better indicators are needed to understand tipping potential. Once identified, positive tipping is enabled by making the desired innovation the most affordable, accessible and/or attractive option. Governments, businesses, civil society and individuals all have a role to play. People understand the need for change and support the transition to a cleaner, healthier world, provided it is done fairly. Success may depend on following a path of least polarisation. The COP30 Presidency has launched a Global Mutirão (meaning "collective efforts") to encourage climate action worldwide.
The report includes case studies on several Earth system tipping points:
- Globally, warm-water coral reefs are experiencing unprecedented mortality under repeated mass bleaching events. With current global warming at about 1.4°C, reefs are passing their thermal tipping point (central estimate 1.2°C, range 1-1.5°C). Even stabilising warming at 1.5°C, warm-water coral reefs are virtually certain (over 99% probability) to tip. This means coral reefs on any meaningful scale will be lost unless the global temperature returns towards 1°C warming or below, although fragments of reef may be preserved with conservation action that minimise other human stressors such as overfishing and pollution. Regional risk assessments and governance are urgently needed to prepare for the increasing loss of ecosystem services provided by reefs.
- The report finds that the temperature rise that would trigger the widespread dieback of the Amazon rainforest due to a combination of climate change and deforestation is lower than previously thought, with the lower end of the estimated range now at 1.5°C, highlighting the need for urgent action. Over a hundred million people depend on the Amazon and it could also be subject to positive social tipping points: inclusive local governance (including by Indigenous People), recognition of traditional knowledge, and targeted investments in conservation and restoration could boost the resilience of people and nature.
- The Atlantic Meridional Overturning Circulation (AMOC) is at risk of collapse below 2°C of global warming. This would result in much harsher winters in north-west Europe, disrupt the West African and Indian Monsoons, and decrease agricultural yields in much of the world - with major impacts for global food security.
