10 New Insights In Climate Science 2025/2026

Insights at a Glance

1. Evidence, uncertainty, and questions around record warm years 2023/2024. While the transition to El Niño conditions helped amplify recent temperature records, these climate fluctuations alone are insufficient to explain the anomalies. The notable rise in Earth’s energy imbalance in recent years suggests that global warming may be accelerating. This reinforces the urgency of narrowing the widening gaps in both emissions reductions and adaptation investments. 

2. Accelerating sea surface warming and intensifying marine heatwaves. The unprecedented pace of ocean surface warming and the intensification of marine heatwaves are driving severe ecological losses, eroding coastal livelihoods, and compounding risks from extreme weather, while also weakening the ocean’s role as a carbon sink. The evidence increasingly points to a dual urgency: accelerate adaptation investments and strengthen global mitigation to prevent further ocean and climate destabilisation. 

3. Global land carbon sink under strain. A marked drop in the global land carbon sink in 2023 raises concerns about a more permanent increase in atmospheric carbon transfer from land and a shrinking ‘remaining carbon budget’. In particular, Northern Hemisphere ecosystems, once considered more stable, are increasingly affected by wildfires and permafrost thawing. The possibility that natural sinks are weakening at the current level of warming underscores the urgent need to accelerate both emissions reductions and carbon removal.

 4. Climate change and biodiversity loss amplify each other. Mounting evidence shows that climate change and biodiversity loss reinforce each other, creating a destabilising feedback loop that threatens both carbon storage and ecosystem resilience. Coordinated action across the Rio Conventions offers a pathway to maximise co-benefits and avoid policy fragmentation by prioritising the protection and restoration of biodiverse ecosystems and safeguarding natural carbon sinks. 

5. Climate change is accelerating groundwater depletion. The global pace of groundwater depletion is rising compared to previous decades, with climate change disrupting aquifer recharge and amplifying socioeconomic demands. The environmental and socioeconomic risks include threats to agriculture and food security, as well as land subsidence and seawater intrusion.

6. Observed and projected climate-driven increase in dengue. Dengue has surged to its largest global outbreak on record. Climate-driven shifts in temperature have expanded mosquito habitats and lengthened transmission periods, compounding the effects of urbanisation, global connectivity, and inadequate waste management. Health systems are already strained under current outbreaks, but projections point to steeper increases this century. 

7. Climate change–related labour productivity and income loss. Heat stress driven by climate change threatens global labour productivity and incomes. While direct losses are greatest in developing countries, the economic impacts will be felt globally, amplified through supply chains and international trade. Projected annual gross domestic product losses are substantially lower in low-emission scenarios, underscoring the urgency for more ambitious mitigation action. 

8. Safe scale-up of carbon dioxide removal is needed to tackle hard-to-abate emissions and climate risks. The scale-up of carbon dioxide removal (CDR) is necessary to complement — not substitute — rapid emissions cuts. The development of strong international guidelines and support for research and innovation is essential to close the ‘CDR gap’ and support both near-term targets and longer-term climate stability, while ensuring environmental and social safeguards.

9. Carbon credit markets – integrity challenges and emergent responses. The rapid expansion of carbon credit markets has come with serious integrity challenges due to systematic flaws, with many projects overstating carbon sequestration and lacking additionality. Heavy reliance on low-quality credits risks delaying direct decarbonisation. Recent progress developing stronger benchmarks, transparency, and market standards, alongside a shift toward viewing credits as contributions rather than substitutes for direct emissions reductions, suggest a path towards more credible and constructive markets. 

10. Policy mixes outperform stand-alone measures in advancing emissions reductions. Carefully designed policy mixes, especially those including carbon pricing, tend to deliver greater emissions reductions than individual measures. Policy mixes that include carbon pricing or reduced fossil fuel subsidies are especially effective; however, policy design must be tailored to the country context. Coordinated crosssectoral approaches and harmonised reporting can help maximise learning and impact.