As the world grapples with accelerating planetary warming, a landmark annual study from more than 70 leading climate experts — including lead contributors to the United Nations Intergovernmental Panel on Climate Change (IPCC) — has delivered a stark dual warning: 2025 has already hit near-miss 1.5°C warming thresholds, and decades of robust global climate tracking is at greater risk of collapse than at any point in modern history. Published in *Earth System Science Data* between the IPCC’s 2023 assessment and its next report due in 2028–2029, the annual *Indicators of Global Climate Change* report paints a clear, alarming picture of a planet out of balance, and systemic failures that could leave policymakers blind to accelerating climate breakdown.
The study confirms that 2025 global average temperatures hit 1.39°C above pre-industrial levels, with 1.37°C of that warming directly driven by human greenhouse gas emissions. On current trajectories, the scientists project that human-caused warming will cross the critical 1.5°C threshold as early as 2030 — a guardrail the 2015 Paris Climate Agreement set to avoid the most catastrophic, irreversible impacts of climate change. Piers Forster, lead author of the study and professor of physical climate change at the UK’s University of Leeds, explained that the planet is now suffering from a record-breaking “Earth energy imbalance,” a measure of the gap between solar energy entering the atmosphere and energy radiated back out to space. “Without human influence, it should be close to zero, but it has been growing since the 1970s and is now at a record high, doubling in recent decades,” Forster noted.
This accelerated warming stems from two overlapping factors: greenhouse gas emissions hitting an all-time annual high, and reduced global aerosol pollution that has eliminated the temporary cooling effect these light-reflecting particles provided. While the rate of emissions growth has slowed, the study finds the remaining carbon budget — the total volume of CO2 that can still be emitted to keep warming below 1.5°C — will be fully exhausted in approximately three years. “Given that greenhouse gas emissions are still on the rise, keeping global warming below this 1.5°C threshold now seems unachievable,” said Aurelien Ribes, a climate scientist at the French meteorological service.
Other key climate indicators tell an equally troubling story. Global sea levels have risen 23 centimeters since 1901, and the rate of increase has accelerated to 3.84 millimeters per year, driven by melting land-based ice and thermal expansion as oceans absorb excess heat. The report added a new metric this year to track ocean stress: the number of annual marine heatwave days, which has tripled since 1991 and hit an average of 65 days in 2025.
Peter Thorne, co-author of the study, professor of physical geography at Ireland’s Maynooth University, and deputy chair of the UN-backed Global Climate Observing System (GCOS), compared climate monitoring to tracking vital signs for a gravely ill patient. “These indicators represent an essential monitoring of the vitals of a patient exhibiting ever increasingly troubling symptoms,” Thorne said. Yet unlike any prior period in his career, Thorne warned that the entire global observation network that underpins these critical readings is facing systemic collapse: “They all rest upon a suite of global observation capabilities which are, for the first time in my lifetime, systematically either actively degrading or at risk.”
The report attributes this unprecedented threat to shifting political priorities and funding cuts across multiple nations, amplified by geopolitical conflicts, post-energy crisis budget constraints, and the resurgence of climate-skeptic political leadership in major economies. It specifically highlights cuts enacted by the second Trump administration in the United States, which ordered the removal of hundreds of deep-sea monitoring instruments that are critical to measuring how oceans absorb excess heat, shape weather patterns, and drive global ocean circulation. Samantha Burgess, climate strategic lead at the European Centre for Medium–Range Weather Forecasts (ECMWF), emphasized the irreplaceable value of these in-situ measurements: “We really need these in-situ observations to continue monitoring the climate.”
Funding threats extend far beyond the U.S., the report confirms. Funding for the UN’s World Meteorological Organization has declined in recent years, and the coordinating GCOS program itself faces sustained funding uncertainty. Ground and atmospheric monitoring networks are shrinking across Africa, the western Pacific, and South America, and the UK recently cut all funding for a research plane that carries out critical atmospheric observation. “So it’s not just one nation, unfortunately,” Burgess noted.
Launched in 2023 to fill the data gap between the IPCC’s decadal assessments, the annual Indicators report is designed to give policymakers up-to-date, robust data to guide climate action. But experts warn that if current funding and policy trends continue, even that critical annual update will be at risk — leaving the world flying blind as climate change accelerates.