The planet's natural carbon sinks are reaching critical limits, absorbing fewer emissions than expected as decades of climate change has weakened their capacity, a new report warns.
Nature-based carbon removal projects are also at risk; climate change is further undermining their long-term reliability and storage capacity, and though large-scale deployment of removals is necessary, it could threaten food security and biodiversity.
The report warns that global climate targets may now face major setbacks.
Launched today ahead of COP30 by more than 70 scientists from 21 countries, the annual 10 New Insights in Climate Science (10 New Insights) report reveals that weaker land sinks - especially forests and soils in the Northern Hemisphere - threaten to derail today's emissions projections while accelerating global warming.
Even the ocean - another vital sink for carbon and heat - is soaking up less carbon dioxide, while more frequent and intense marine heatwaves ravage ecosystems and coastal livelihoods.
The report highlights that large-scale deployment of nature-based removals could come at a cost to food security and biodiversity, as these projects compete with both for land space.
The report underscores that expectations for nature-based carbon removal far exceed what current projects and natural sinks can deliver.
According to scientists "novel", or tech-based, removals are required as well alongside deep emission cuts to right the course.
The report also finds that voluntary carbon credit markets, in which carbon removal projects can operate, are touted as another potential solution, but endure ongoing credibility issues and require stronger benchmarks and market standards to ensure integrity.
"We've long relied on forests and soils to quietly clean up our carbon mess - but their capacity is faltering," said Sabine Fuss, department leader at the Potsdam Institute for Climate Impact Research and member of the report's editorial board.
"That means we may be underestimating the current emissions gap as well as the pace of future warming."
A joint initiative of Future Earth, The Earth League, and the World Climate Research Programme, the 10 New Insights report distils the latest advances in climate science from the past 18 months into 10 concise insights, serving as a trusted resource for policymakers.
It comes as negotiators prepare for COP30, a pivotal moment 10 years after the Paris Agreement and amid a new wave of updated climate targets from countries worldwide.
Professor Peter Cox, Director of the Global Systems Institute at the University of Exeter, said: "It was a challenge to identify just 10 new insights because the climate system is changing rapidly in so many ways. In short, human impact on the climate system has never been clearer, and the need for collaborative international action has never been more acute."
As the latest round of Nationally Determined Contributions (NDCs) emerges, and climate scepticism peaks, countries cannot afford to continue planning on outdated information.
"The climate negotiations must be guided by science, and the 10 New Insights provide the best summary of the latest updates in climate science.," said Johan Rockström, co-chair of The Earth League and a member of the report's editorial board.
"These insights provide overwhelming evidence that we are in a state of climate urgency, which means that COP30 must be the COP of implementation - we can no longer afford new promises without delivery.
"The focus for policymakers must be on cutting emissions decisively, protecting and restoring nature, and strengthening the systems that sustain us."
The report's other insights examine the factors contributing to the record warmth of 2023 and 2024, with extreme heat placing unprecedented pressure on freshwater resources, human health and livelihoods.
New research synthesised in the report reveals how rising temperatures are lowering groundwater levels, vital in many regions for agriculture.
Climate change is also fuelling the spread of mosquito-borne diseases such as dengue fever, as higher temperatures expand the insect's habitat.
"After witnessing the largest global outbreak of dengue on record last year, health systems are under immense strain. The findings synthesised in the 10 New Insights report are a stark reminder that no one is immune to the impacts of climate change - its consequences are global, interconnected, and already at our doorstep," said Kristie Ebi, a global health professor at the University of Washington and a member of the report's editorial board.
In addition to human health, the report also explains how heat stress is driving a sharp decline in labour productivity, impacting incomes and leading to wider economic instability.
For example, just 1°C of warming is expected to expose more than 800 million people in tropical regions to unsafe levels of heat stress, potentially reducing their working hours by as much as 50%.
Ultimately, this year's report shows that nearly every major climate risk stems from one root cause - the failure to cut emissions at the speed and scale required.
Relying on nature and markets alone will not solve the crisis.
Record-breaking temperatures in 2023 and 2024, accelerating ocean warming, and the growing strain on ecosystems and societies are all symptoms of delayed action.
The message for COP30 is unequivocal: the science is clear, the solutions and limitations are known, and now is the time to deliver.
Full list of 10 insights:
1. Record warming 2023/24: Evidence on the drivers behind recent global temperature jumps suggests a possible acceleration of global warming.
2. Accelerated ocean warming: Rapid ocean warming and intensifying marine heatwaves are harming ecosystems and increasing extreme weather risks.
3. Strain on land carbon sinks: Global land carbon sinks are showing signs of stress as the planet continues to warm.
4. Climate-biodiversity feedback: Biodiversity loss and climate change reinforce each other in a destabilising loop.
5. Declining groundwater levels: Climate change is accelerating groundwater depletion, increasing risks to agriculture and urban settlements.
6. Climate-driven dengue outbreaks: Rising temperatures are creating more favourable conditions for the mosquitoes that spread dengue, driving the disease's geographical spread and intensity.
7. Impacts on labour productivity: Increasing heat stress is projected to reduce working hours and economic output.
8. Scaling carbon dioxide removal (CDR): Scaling CDR responsibly is essential, but with a focus on hard-to-abate emissions and limiting climate overshoot.
9. Carbon market integrity challenges: Strengthening standards and transparency in voluntary carbon markets is needed to ensure real mitigation benefits.
