Each year, The Earth League, Future Earth, and the World Climate Research Program invite leading scientists from around the world to evaluate the most pressing findings in climate change research. Their assessments are summarized into 10 concise insights, offering a critical synthesis to guide policy and societal responses during this decisive decade. This article highlights the key findings of the 10 New Insights in Climate Science for 2025/2026.
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Global climate indicators continue to demonstrate escalating risks. The World Meteorological Organization reported global average temperatures reaching 1.55 °C above pre-industrial levels, approaching the Paris Agreement threshold of 1.5 °C. This record warming coincided with unprecedented ocean heat content, sea level rise, glacier mass loss, and extreme weather events, highlighting the intensifying human and economic impacts.
Current mitigation efforts remain insufficient, and the accelerating pace of climate change underscores the urgent need for science-driven guidance, making these 10 insights a timely and essential resource for informing policy and societal responses.
2025/2026's 10 New Insights in Climate Science
1. Record Temperatures and Scientific Uncertainties of 2023/2025
Global surface temperatures in 2023 and 2024 surpassed previous records, reflecting an exceptional warming signal. While the transition from La Niña to El Niño contributed to elevated temperatures, the magnitude and persistence of the heat anomaly exceeded expectations based on long-term trends and typical interannual variability.
This period also coincided with a pronounced increase in Earth’s energy imbalance, driven by rising greenhouse gas concentrations and reduced planetary reflectivity due to declining cloud cover and ice, with 15-20 % of the absorbed heat warming the atmosphere and land, while the majority accumulated in the oceans.
A key factor of this has been the decline in sulphate aerosol pollution, including an 80 % reduction in sulfur emissions from international shipping since 2020, which decreased cloud reflectivity and contributed to surface warming, particularly over mid-latitude Northern Hemisphere oceans.
Continued reductions in anthropogenic aerosol emissions over land, particularly in East Asia, have further intensified warming since 2010, underscoring the combined impact of greenhouse gas emissions and aerosol changes on recent extreme temperature anomalies.
Significant uncertainties remain regarding the drivers of record heat, as aerosol-cloud interactions and cloud feedback are complex to represent accurately in global models. However, the potential acceleration of global warming underscores the urgency of strengthening Nationally Determined Contributions (NDCs), expanding deployment of carbon dioxide removal, and accelerating transformation across energy systems.
2. Ocean Warming and Marine Ecosystem Disruption
Global ocean surface temperatures rose at unprecedented rates between April 2023 and June 2024, breaking monthly records for 13 consecutive months. During this period, temperatures reached 0.6 °C above the 1981-2019 average and 0.9 °C above pre-industrial levels, exceeding 2015-2016 records by 0.25 °C.
Marine heatwaves intensified in frequency, duration, and intensity, with annual heatwave days increasing by 54 % and subsurface events warming 0.1-1° C per decade, outpacing mean ocean warming.
These events amplified land heatwaves, intensified hurricanes, and resulted in substantial economic losses, including USD 7.5-8.5 billion following Cyclone Gabrielle and USD 1.4 billion due to the closure of the Peruvian anchovy fishery.
Heatwaves also reduced oceanic carbon uptake by an estimated 8 % and drove widespread declines in macroalgae, seagrass, and corals, culminating in the fourth global mass coral bleaching event in 2024.
The escalating ecological and economic impacts of marine heatwaves underscore the need for climate-resilient marine policies, early warning systems, and multilateral cooperation to support coral restoration, adaptive fisheries, and coastal protection.
Addressing these challenges also requires accelerated global mitigation efforts, including the rapid phase-out of fossil fuels, the expansion of renewable energy, improved energy efficiency, and enhanced carbon dioxide removal.
3. Global Carbon Sink Under Strain
Terrestrial ecosystems exhibited a marked reduction in carbon uptake in 2023, as drought, heatwaves, wildfire activity, and permafrost thawing weakened processes that previously stabilized the land carbon sink.
The sink declined to 2.3 ± 1 GtC per year, far below the strong 2022 value and the recent decadal average, indicating that both short-term climate variability and long-term warming are undermining carbon storage.
Tropical regions experienced a 58 % drop in uptake, while high-latitude systems recorded losses driven by unprecedented Canadian boreal wildfires that emitted 0.65 ± 0.08 GtC in 2023. Northern ecosystems show declining stability, with biomass trends reversing after 2016 due to insect outbreaks, drought, and heat-related mortality.
The permafrost zone, although still a net CO2 sink overall, now has roughly one-third of its area acting as a carbon source, with the tundra biome exhibiting a shift away from net carbon uptake. Accounting for all greenhouse gases and disturbance-related emissions, the permafrost region may already be a net source of approximately 0.14 GtC per year.
Uncertainties remain regarding ecosystem recovery, as current vegetation models underestimate post-disturbance regrowth, limiting the accuracy of future carbon-cycle projections.
4. Climate Change and Biodiversity Loss
Climate change is accelerating global biodiversity, which in turn weakens the biological processes that regulate carbon storage. This creates a detrimental, reinforcing feedback loop that intensifies global warming.
For example, plant diversity is central to carbon retention, but its reduction could generate emissions ranging from 7 to 146 GtC over the coming decades, representing a substantial risk to limiting warming to 1.5 °C or 2 °C. Conversely, diversity conservation could abate emissions by approximately 2 to 3 GtC per year. This dynamic extends to agroecosystems, where increased plant diversity enhances soil carbon retention, particularly in arid biomes.
Trophic interactions significantly modulate carbon dynamics; for instance, anthropogenic defaunation in tropical forests has reduced ecosystem carbon storage by up to 26 %, demonstrating how biodiversity loss propagates across trophic levels to alter both above- and below-ground carbon cycling.
To address these interconnected crises, achieving the targets of the Kunming-Montreal Global Biodiversity Framework offers a clear pathway to mitigate carbon losses through ecosystem maintenance and restoration. This requires harmonizing climate, biodiversity, and land degradation conventions to prevent policy fragmentation and demands that financial mechanisms prioritize native, multi-species restoration over monocultures.
Integrating biodiversity integrity indicators with national carbon accounting, underpinned by ecological science and Indigenous knowledge systems, will enhance monitoring and verification of the ecological processes that sustain carbon stocks.
5. Accelerating Groundwater Depletion and Climate Change Impacts
Global groundwater depletion is intensifying, driven by the combined effects of climate change and rising socio-economic demands. Since 1960, global groundwater withdrawals have tripled from approximately 312 km³ per year to over 1000 km³ per year, predominantly for irrigation.
GRACE satellite data (2002-2024) confirm this unsustainable trend, revealing pronounced depletion rates in critical agricultural regions, including Northwestern India (0.66 cm/yr) and the Central Valley (0.44 cm/yr).
Climate change is also altering groundwater recharge by shifting snowmelt timing, reducing infiltration, and intensifying drought and extreme rainfall events. If not stopped, this could lead to land subsidence, threatening both urban and agricultural infrastructure, as well as saltwater intrusion into coastal aquifers.
Therefore, addressing groundwater sustainability requires immediate, integrated, and multi-level governance that harmonizes escalating human water demands with robust transboundary water cooperation and regional adaptation frameworks.
6. Climate-Driven Acceleration of Global Dengue Transmission
Rising temperatures are accelerating dengue transmission by enhancing mosquito development rates, increasing viral replication, and expanding the geographic range of Aedes aegypti and Aedes albopictus.
Warmer conditions lengthen transmission seasons and allow these vectors to establish in regions previously unsuitable, contributing to a 10.7 % and 46.3 % expansion in climatically suitable areas for the two species between 1951 and 2023.
This shift coincided with a record 14.2 million global dengue cases in 2024 and an estimated 100-400 million infections annually, where secondary infections carry a heightened risk of severe disease.
Regional impacts highlight the scale of this trend, with over 13 million cases in the Americas in 2024, a ninefold increase in cases in Africa between 2019 and 2023, and local transmission emerging in temperate parts of Europe.
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Addressing this rapid global expansion of dengue requires integrating health into climate action, supported by international collaboration, financing, and intersectoral coordination through national adaptation plans.
In addition, proactive measures, including enhanced surveillance, early-warning systems, integrated vector management, improved water and waste management, and targeted vaccination, can also reduce transmission, limit outbreaks, and protect vulnerable populations from the growing climate-driven dengue risk.
7. Climate Change-Related Labor Productivity and Income Loss
Heat stress is one of the most direct and well-documented mechanisms through which climate change affects economic activity. It reduces labor capacity by limiting safe working hours, impairs physical and cognitive performance, and increases the risk of heat-related illness and mortality, thereby directly lowering productivity and income.
In the coming years, an additional 1 °C of global warming is projected to expose over 800 million people in tropical regions to unsafe heat levels, potentially reducing working hours by up to 50 %.
While direct effects are apparent in developing countries, global supply chains amplify economic consequences, with annual GDP reductions estimated at 0.1-0.8 % under low-emissions scenarios and 1.4-4.5 % under high-emissions scenarios.
The magnitude of projected heat-related economic losses underscores the urgent need for ambitious climate mitigation and policy measures. Adaptation strategies should prioritize investments in cooling infrastructure, regulated work schedules during extreme heat, and sector-specific occupational heat-stress plans.
Integrating labor considerations into national frameworks, such as the Just Transition Work Program, could also enhance workforce resilience, safeguard incomes, and support equitable adaptation to climate-induced heat stress.
8. Safe Scale-Up of CO2 Removal to Address Hard-to-Abate Emissions
Carbon Dioxide Removal (CDR) is essential to complement deep emissions reductions and achieve Paris Agreement targets, primarily by offsetting residual emissions from hard-to-abate sectors such as international aviation and heavy industry.
CDR employs conventional approaches, including afforestation, alongside novel methods such as Bioenergy with Carbon Capture and Storage (BECCS), Direct Air Capture with Carbon Storage (DACCS), enhanced weathering, and biochar.
However, nature-based removals are constrained by slow carbon uptake, risks of reversal, and land scarcity, while novel methods remain limited in scale and require substantial energy and material inputs.
As a result, global net land-use emissions (~4.4 Gt CO2 per year) continue to exceed removals (~2 Gt CO2 per year), creating a significant “CDR gap” and highlighting the urgency for safe, large-scale deployment to stabilize temperatures and mitigate climate overshoot.
Scaling CDR must be paired with deep emissions reductions, robust safeguards, and transparent policies to prevent greenwashing and ensure it supplements, not replaces, direct mitigation. Policies should provide guidance on integrating CDR into NDCs and emissions trading schemes, distinguishing between permanent and temporary storage.
Moreover, governments should consider CDR procurement as a public good to accelerate readiness, close the CDR gap, and incentivize private-sector deployment across diverse pathways.
9. Carbon Credit Markets: Integrity Challenges and Emerging Responses
Voluntary carbon markets have expanded rapidly, yet concerns persist about the quality and credibility of credits. Evidence indicates that many emissions-avoidance projects lack additionality, and nature-based removals often overestimate sequestration, limiting their reliability as substitutes for fossil-fuel reductions. Most corporate buyers rely on low-cost, low-quality credits, creating a “delay effect” that diverts attention from direct decarbonization.
Credit issuance, generated through activities such as forest management and renewable energy deployment, rose from 200 million in 2020 to 350 million in 2021 but declined to 290 million in 2024 due to quality concerns, with analyses suggesting that less than 16 % of credits represent genuine emissions reduction.
Nature-based removal projects, including afforestation, face constraints from slow absorption rates, reversal risks, and overestimation of sequestration, demonstrating that current market structures cannot reliably substitute for direct reductions in fossil fuel emissions.
Therefore, strengthening market integrity is essential, including adopting robust governance frameworks, standardized quality benchmarks, and transparent rating systems.
Credits should be treated as supplementary mitigation measures rather than replacements for direct decarbonization, with regulatory oversight and adherence to international standards, such as those outlined in Article 6.4 of the Paris Agreement, to ensure transparency, accountability, and a measurable climate impact.
10. Policy Mixes Outperform Stand-Alone Measures in Emissions Reductions
Evidence shows that carefully designed policy mixes outperform stand-alone measures, as they address multiple objectives beyond emissions reductions, including cost-effectiveness, equity, innovation, energy security, and political feasibility.
Combining instruments such as carbon pricing with reduced fossil fuel subsidies generally produces larger reductions than relying solely on non-price measures.
For instance, simulations in France demonstrate that pairing gas boiler bans with subsidy schemes will increase the likelihood of achieving carbon neutrality, lower system costs, and support equity objectives.
However, effective policy mixes require robust governance, cross-jurisdictional coordination, iterative learning, and transparent monitoring to manage overlaps, rebound effects, and unintended trade-offs.
Policymakers should integrate political feasibility, public opinion, equity, and justice to enable the successful implementation and durability of ambitious, multi-objective policy mixes.
Ultimately, adopting integrated, well-governed policy mixes ensures that climate objectives are achieved efficiently while balancing social, economic, and environmental outcomes across sectors and regions.
Conclusion
The 10 New Insights in Climate Science for 2025/2026 highlight the accelerating pace and broad impacts of climate change across environmental, economic, and social systems. This provides essential guidance for policymakers, researchers, and stakeholders to advance resilience and achieve the goals of the Paris Agreement.
References and Further Reading
Future Earth, The Earth League, WCRP (2025). 10 New Insights in Climate Science 2025/2026. https://10insightsclimate.science/
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