Global climate indicators continue to signal increasing cause for concern. In early 2025, the World Meteorological Organization (WMO) confirmed that 2024 was the warmest year on record, with average temperatures reaching 1.55°C (± 0.13°C) above pre-industrial levels. While this is not yet a breach of the Paris Agreement goal to keep long-term global warming below +1.5°C, it is a stark indication of just how close the world is to getting there. This exceptional warming was accompanied by record-breaking ocean heat content and sea level rise, dramatic glacier mass loss, and the second-lowest Antarctic sea ice extent observed.1, The ongoing rise in global temperatures has fueled more frequent and intense extreme weather, including heatwaves, droughts, wildfires, storms, and floods, causing substantial human and economic losses.
Despite these escalating risks, anthropogenic greenhouse gas (GHG) emissions have continued to increase through 2023 and 2024, further driving the steady rise in atmospheric greenhouse gas concentrations.2, Current global mitigation efforts remain insufficient. If fully implemented, the latest round of Nationally Determined Contributions (NDCs) would cut global emissions by just 5.9% (range: 3.2–8.6%) by 2030 compared to 2019 levels — far short of the 28% reduction needed to keep warming below 2°C, or the 42% necessary for 1.5°C by the end of the century. The urgency to bridge the gaps in both ambition and implementation is heightened in the context of repeated delays by most parties to submit the updated NDCs. By early October 2025, only 62 countries, covering just 31% of all GHG emissions, had submitted updated NDCs. Several major emitters, including China, India, and the European Union are yet to submit theirs. The lack of momentum on ambition and implementation presents one of the most pressing challenges for COP30 in Belém, Brazil.
With the Paris Agreement’s rulebook now largely complete and mounting scientific evidence about the urgency of accelerating climate action, COP30 is widely seen as an “implementation COP”: a pivotal moment in climate diplomacy to interrogate and overcome the persistent barriers holding back real-world progress on mitigation and adaptation. Parties must agree on ways to turn the outcomes of the Global Stocktake (COP28, Dubai), especially the transition away from fossil fuels, into concrete actions for course correction. To this end, discussions about how to reform the COP process for the “post-negotiation phase” will continue to gather momentum. Climate finance remains a contentious unresolved issue, fundamental for enabling collective action. Following the decision of a New Collective Quantified Goal of USD 300 billion/yr (COP29, Baku), widely recognised as inadequate, the Baku-Belém Roadmap was set up to find ways to reach the aspirational goal of USD 1.3 trillion/yr by 2035. While the geopolitical context is particularly challenging, these priorities require reinvigorating multilateralism and multilevel governance.
Science has a critical role in informing governance for the implementation of climate commitments at international, national, and subnational levels. The Intergovernmental Panel on Climate Change (IPCC) is the primary scientific body informing the United Nations Framework Convention on Climate Change (UNFCCC) process. However, given their comprehensiveness and procedural demands, each Assessment Report from the IPCC has a multi-year production cycle. The 10 New Insights in Climate Science initiative is an annual collaborative effort, to curate and synthesise key messages across diverse fields of climate change research, based on the latest relevant peer-reviewed literature. This year, the synthesis is built on the collective effort of over 70 researchers, based on input from more than 150 experts across the world. The ultimate aim is to support the timely uptake of new scientific evidence in policy processes and international governance spaces.
The first four insights of this year’s report revolve around Earth system processes and highlight the concerning possibility that global warming is accelerating. Recent analyses of global climate indicators in 2023 and 2024 point to an elevated Earth energy imbalance (Insight 1), a significant surge in ocean heat uptake and marine heatwaves (Insight 2), and a sharp drop of the global land carbon sink (Insight 3). These geophysical developments underscore the narrowing window available to minimise temperature overshoot and stabilise the climate within the Paris Agreement temperature range. Furthermore, new analyses show biodiversity loss in itself can exacerbate climate change, as it underpins ecosystem functions of carbon uptake and storage (Insight 4). This first cluster of insights reinforce the urgency for ambitious mitigation plans and effective implementation.
Next, three insights focus on impacts of climate change on water security, human health, and livelihoods and productivity: acceleration of groundwater decline (Insight 5), the ongoing and future expansion of dengue (Insight 6), and increasing heat-induced losses in labour productivity and global income (Insight 7). These impacts are already affecting populations in different regions, but risks are significantly larger at higher levels of temperature overshoot. Adaptation efforts must be rapidly scaled up to reduce the increasing socioeconomic consequences. However, there are limits to adaptation, and in the absence of ambitious mitigation, healthcare systems could be overwhelmed and economies severely weakened.
The third and final cluster of insights focuses on key aspects for enhancing mitigation. Two mitigation approaches that have a vital but complementary role to direct GHG emissions reductions are carbon dioxide removal (CDR) and carbon credit markets. Responsibly scaling CDR is a necessity for stabilising the climate, especially in the context of temperature overshoot, but deployment remains far below the levels needed (Insight 8). With voluntary carbon markets (VCM), the pervasiveness of low-quality credits stands out as a key problem, which might contribute to further delaying direct decarbonisation (Insight 9). Closing the ‘CDR gap’ and addressing the systemic integrity flaws in VCMs require comprehensive policy frameworks. Fortunately, there is now a wealth of knowledge on effective climate policies that builds on four decades of policy experimentation and recent systematic reviews. A key lesson is that carefully tailored policy mixes, especially those including carbon pricing, tend to achieve greater and more robust emissions cuts (Insight 10).
We hope that the 10 New Insights in Climate Science 2025/2026 will reach Party and Observer delegations to the UNFCCC, help inform their positions and arguments, and ultimately be reflected in the outcomes of COP30 in Belém, Brazil, and beyond. In particular:
- Strengthening the operationalisation of Global Stocktake outcomes through enhanced NDC transparency and accountability mechanisms that embed science-based emission reduction pathways consistent with the Paris Agreement goals – specifically by establishing standardised progress indicators and reporting frameworks that track countries’ progress transitioning away from fossil fuels.
- Promoting the integration and coordination between the UNFCCC and CBD to strengthen forest conservation and restoration to safeguard biodiversity and land carbon sinks. Specifically, by advancing the operationalisation of the CBD COP16 decision on biodiversity-climate coordination.
- Finalising and formally adopting the list of 100 adaptation indicators proposed under the UAE-Belém Work Programme, providing the necessary political guidance to resolve outstanding divergences regarding shared definitions and overarching conceptual issues regarding the indicators related to ‘means of implementation’.
- Formally recognising distinct roles of CDR in climate mitigation, specifically to counterbalance hard-to-abate residual emissions and, eventually, to enable net-negative emissions. To avoid delaying or deterring direct decarbonisation, separate targets and accounting are required for emissions reductions versus carbon removals to ensure transparent reporting in NDCs and Article 6 transactions.
- Adopting stringent quality standards for both voluntary and compliance mechanisms as part of the operationalisation of high-integrity carbon markets under Article 6. This requires robust measurement, reporting, and verification systems; and safeguards for permanence of stored carbon and for risks of reversibility; and testing of additionality and prevention of double-counting.
- Establishing an official knowledge-sharing platform that systematically consolidates and synthesises evidence on effective climate mitigation policies and policy combinations.
The science underpinning each of the insights presented in this report is described in more detail and with all the supporting references in:
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