Land carbon sinks lag while rising temperatures spread disease and threaten incomes

The planet’s natural carbon sinks are reaching critical limits, absorbing fewer emissions than expected as decades of climate change have weakened their capacity, a new report warns.

Nature-based carbon removal projects are also under threat; climate change further compromises their long-term reliability and storage capacity, and while large-scale deployment of harvesting is necessary, it could threaten food security and biodiversity.

The report warns that global climate goals could 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 report reveals that weaker land sinks, particularly forests and soils in the Northern Hemisphere, threaten to derail current emissions projections while accelerating global warming.

Even the ocean – another vital sink of carbon and heat – is absorbing less carbon dioxide, while more frequent and intense marine heatwaves ravage coastal ecosystems and livelihoods.

The report highlights that large-scale deployment of natural harvests could come at a cost to food security and biodiversity, as these projects compete with both for land space.

The report highlights that expectations for naturally occurring carbon removal far exceed what current projects and natural sinks can deliver.

Scientists say “novel” or technology-based removals are also needed, alongside deep emissions reductions, to turn the situation around.

The report also finds that voluntary carbon credit markets, in which carbon removal projects can operate, are touted as another potential solution, but suffer from persistent credibility issues and require stricter market benchmarks and standards to ensure integrity.

“We have long relied on forests and soils to quietly clean up our carbon mess, but their capacity is waning,” said Sabine Fuss, head of department at the Potsdam Institute for Climate Impact Research and member of the report’s writing committee.

“This means we may be underestimating the current emissions gap as well as the rate of future warming.”

A joint initiative of Future Earth, the Earth League and the World Climate Research Program, the 10 New Insights report distills the latest advances in climate science over 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 around the world.

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, as the climate system is changing rapidly in many ways.

As the latest round of Nationally Determined Contributions (NDCs) emerges and climate skepticism reaches fever pitch, countries cannot afford to continue planning based on outdated information.

“Climate negotiations must be guided by science, and the 10 new perspectives provide the best summary of the latest updates in climate science,” said Johan Rockström, co-chair of the Earth League and member of the report’s writing committee.

“This information provides irrefutable proof that we are in a state of climate emergency, which means that COP30 must be the COP of implementation: we can no longer afford to make new promises without being kept.

“Policymakers must focus on decisively reducing emissions, protecting and restoring nature, and strengthening the systems that support us.”

Other analyzes in the report examine factors contributing to record heat in 2023 and 2024, with extreme heat putting unprecedented pressure on freshwater resources, human health and livelihoods.

New research synthesized in the report reveals how rising temperatures are lowering groundwater levels, vital for agriculture in many regions.

Climate change is also fueling the spread of mosquito-borne diseases such as dengue fever, as higher temperatures expand the insect’s habitat.

“After witnessing the largest global dengue outbreak on record last year, health systems are under immense pressure. The findings synthesized in the 10 New Insights report are a stark reminder that no one is immune from the impacts of climate change: its consequences are global, interconnected and already upon us,” said Kristie Ebi, professor of global health at the University of Washington and member of the report’s writing committee.

Besides human health, the report also explains how heat stress leads to a sharp decline in labor productivity, impact on income and broader economic instability.

For example, warming of just 1°C is expected to expose more than 800 million people in tropical regions to dangerous levels of heat stress, potentially reducing their working hours by up to 50%.

Ultimately, this year’s report shows that almost all major climate risks stem from a single cause: the failure to reduce emissions at the speed and scale required.

Relying solely on nature and markets will not solve the crisis.

Record temperatures in 2023 and 2024, accelerating ocean warming and increasing pressure on ecosystems and societies are all symptoms of late action.

The message from COP30 is unequivocal: the science is clear, the solutions and limits are known, and now is the time to act.

Complete list of 10 insights:

1. Record warming in 2023/24: Data on the factors behind recent global temperature rises suggest a possible acceleration of global warming.

2. Accelerated ocean warming: Rapid ocean warming and intensifying marine heatwaves harm ecosystems and increase extreme weather risks.

3. Pressure on terrestrial carbon sinks: Global terrestrial 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 destabilizing loop.

5. Declining groundwater levels: Climate change is accelerating groundwater depletion, increasing risks to agriculture and urban settlements.

6. Climate-related dengue outbreaks: Rising temperatures create more favorable conditions for mosquitoes that spread dengue, thereby leading to the geographic spread and intensity of the disease.

7. Impacts on labor productivity: Increased heat stress is expected to reduce working hours and economic output.

8. Increase carbon dioxide removal (CDR): It is essential to expand CDR responsibly, but with a focus on hard-to-reduce emissions and limiting climate overshoot.

9. Carbon market integrity challenges: Strengthening the standards and transparency of voluntary carbon markets is necessary to ensure real mitigation benefits.

10. Effective policy combinations: Carefully designed policy combinations are more effective than isolated measures in achieving deep and lasting emissions reductions.