Earth enters ‘new reality’ as coral reefs reach first climate tipping point

The world faces a “new reality” as we reach the first of many Earth system tipping points that will cause catastrophic damage unless humanity takes urgent action, according to a report published by the University of Exeter and international partners.

Ahead of the COP30 summit, ministers gathered and the second Global Tipping Points report found 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 occurs and, unless global warming the situation is reversed: vast reefs as we know them will be lost, although small refuges may survive and should be protected.

We are on the cusp of new tipping points with devastating risks to people and nature: the irreversible melting of polar ice sheets, the collapse of major ocean currents and the extinction of the Amazon rainforest, where COP30 will be held.

With global warming set to exceed 1.5C, the report, prepared by 160 scientists from 87 institutions in 23 countries, argues that countries must minimize temperature rises to avoid crossing new tipping points. Every fraction of a degree and every year spent above 1.5°C matters.

The report says that actions aimed at creating “positive tipping points” of self-propelled change, such as the adoption of green technologies, now offer the only credible path to a secure, equitable and sustainable future.

Researchers are working with Brazil's COP30 presidency to ensure watershed moments are included on the summit's agenda.

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 reshape our world with devastating consequences for people and nature. This requires immediate, unprecedented action from COP30 leaders and policymakers around the world.

“In the two years since the first Global Tipping Points report was published, some areas have seen dramatic global acceleration, including the adoption of solar energy and electric vehicles. But we need to do more—and move faster—to seize the positive opportunities of the inflection point. By doing so, we can dramatically reduce greenhouse gas emissions and move the world away from catastrophic tipping points and towards prosperity. sustainable future“

Dr Mike Barrett, chief scientific adviser to WWF UK and co-author of the report, said: “The findings of this report are incredibly worrying. That warm-water coral reefs are passing their temperature tipping point is a tragedy for nature and the people who rely on them for food and income.

“This grim situation should be a wake-up call: unless we act decisively now, we will also lose the Amazon rainforest, ice sheets and vital ocean currents. In this scenario, we would be looking at a truly catastrophic outcome for all of humanity.

“On the way to COP30 climate talksIt is vital that all parties understand the gravity of the situation and the scale of what we all stand to lose if the climate and nature crises are not addressed. Solutions are within our reach. Countries must show political courage and leadership to work together to achieve these goals.”

The nature of abrupt and irreversible Earth system tipping points means they pose a different type of threat to other countries, the report says. environmental problemsand that current policy and decision-making processes are inadequate to respond. Global action must include accelerating emissions reductions and increasing carbon removal to minimize temperature rises.

The expected consequences of reversal processes need to be considered in risk assessments, adaptation policies, loss and damage mechanisms, and human rights litigation.

Dr Manyana Milkoreit, from the University of Oslo, said: “Modern political thinking usually does not take tipping points into account. Tipping points present unique governance challenges compared to other aspects of climate change or environmental degradation, requiring both governance innovation and reform of existing institutions.

“Averting tipping points requires pre-designed mitigation pathways that minimize peak global temperatures, duration of exceedance above 1.5°C, and duration of return below 1.5°C. To achieve this goal, approaches to sustainable carbon removal must be rapidly scaled up.”

The report's authors are working with Brazil's COP30 Presidency on an Agenda for Action as a platform for accelerating climate change plans and driving self-reinforcing changes across sectors – from agriculture to energy, forests to cities – to achieve low carbon and climate resilient global transformation.

COP30 President-designate in Brazil, Ambassador André Corrêa do Lago, said: “As part of the global mobilization against climate change – our “Global Mutirao” – the COP30 President invited community leaders, scientists and scholars to explore the best available science and ancient wisdom on how our institutions can gain exponential capacity in deploying solutions and versatility in response to the climate crisis, including through flexible, iterative and adaptive capabilities. I welcome the Global Tipping Points report as a positive and timely response to our invitation.

“The report is encouraging and sobering evidence that humanity can still choose to change and evolve towards a secure, prosperous and just future.”

The report highlights progress towards positive inflection points and opportunities for a cascade of positive change:

• Positive turning points have already been passed. in solar photovoltaic and wind energy globally, as well as in the adoption of electric vehicles, battery storage and heat pumps in leading markets. These transitions can still be accelerated. Coordinated policy actions at “super-leverage points” could trigger a cascade of positive tips across all interacting sectors (e.g., energy, transportation, and heating), resulting in increased tips across all sectors. Once replaced, polluting technologies are unlikely to return because new options are cheaper and better. Social relationships are also changing. Concern about climate change is growing around the world, and even a small number of people can tip the majority.
• More positive turning points are approaching in sectors including freight transport. As a COP30 host country, Brazil has enormous potential to produce green steel, green hydrogen and green ammonia, helping to jump-start these critical technologies around the world. Positive tipping points can quickly restore nature and biodiversity. Restoring ecosystems can restore degraded systems to health, and shifting to more sustainable consumption and production patterns can create inflection points in food and fiber supply chains that end deforestation and ecosystem transformation.
• We need to identify and catalyze many more positive inflection points.. More accurate indicators are needed to understand tipping potential. Once identified, positive tipping becomes possible as the desired innovation becomes the most accessible, affordable, 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, as long as it is done fairly. Success may depend on following the path of least polarization. The COP30 Presidency launched Global Mutirão (meaning “collective effort”) to encourage action on climate change around the world.

The report includes case studies of several Earth system tipping points:

• Worldwide, warm-water coral reefs are experiencing unprecedented mortality with repeated mass bleaching events. With current global warming of about 1.4°C, reefs are passing a tipping point (central estimate 1.2°C, range 1-1.5°C). Even if warming stabilizes at 1.5°C, warm-water coral reefs are almost certain (more than 99% likely) to capsize. It means coral reefs on any meaningful scale will be lost unless global temperatures return to warming of 1°C or less, although reef fragments can be preserved through conservation actions that minimize other human stressors such as overfishing and pollution. Regional risk assessments and management are urgently needed to prepare for the increasing loss of ecosystem services provided by reefs.
• The report found that rising temperatures that will trigger widespread extinction of the Amazon rainforest. due to a combination of climate change and deforestation, is lower than previously estimated: the lower end of the estimated range is now 1.5°C, highlighting the need urgent measures. Over one hundred million people depend on the Amazon, and it can also have positive social impacts. turning points: Inclusive local governance (including by indigenous peoples), recognition of traditional knowledge and targeted investments in conservation and restoration can improve the resilience of people and nature.
• The Atlantic Meridional Overturning Circulation (AMOC) is at risk of collapse below 2°C global warming. This will lead to much harsher winters in north-west Europe, disrupt the West African and Indian monsoons and reduce crop yields across much of the world, with major impacts on global food security.

Professor Lenton concluded: “Only through a combination of decisive policy and civil society action can the world change its trajectory from facing the existential risks of an Earth system tipping point to seizing the positive opportunities of a tipping point.”