Land and ocean carbon sinks weakening, and other new insights from climate science

The “10 New Insights in Climate Science”, a joint initiative by Future Earth, The Earth League, and the World Climate Research Programme, highlight that weaker land sinks, especially in the Northern Hemisphere, threaten to derail today’s emissions projections while accelerating global warming.

“We’ve long relied on forests and soils to quietly clean up our carbon mess - but their capacity is faltering,” says Sabine Fuss, research department co-head at PIK 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.”

In addition to land sinks, the ocean is soaking up less carbon dioxide. The authors stress that expectations for nature-based removals exceed what current projects and natural sinks can deliver. Though carbon dioxide removals offer a solution to protect and expand carbon sinks, the report cautions that large-scale deployment could come at the cost of food security and biodiversity. Technology-based carbon removals will be required, alongside deep emission cuts, to tackle climate change. Voluntary carbon markets, while offering potential to scale up carbon removal projects, still face major credibility challenges and require stronger benchmarks and standards to ensure integrity.

“COP30 must be the COP of implementation” 

“These insights provide overwhelming evidence that we are in a state of climate urgency. COP30 must be the COP of implementation. We can no longer afford new promises without delivery,” says PIK Director Johan Rockström, co-chair of The Earth League and a member of the report’s editorial board. “The focus for policymakers must be on cutting emissions decisively, protecting and restoring nature, and strengthening the systems that sustain us.”

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.

10. Effective policy mixes: Carefully designed policy mixes are more effective than single
measures in achieving deep and lasting emission cuts.