The past 11 years have marked an unprecedented streak of extreme global temperatures, with 2025 ranking as the second or third hottest year since modern observations began, according to the World Meteorological Organization’s latest State of the Global Climate 2025 report. The findings, released this week, highlight the relentless pace of climate change, revealing record levels of atmospheric carbon dioxide, ocean heat accumulation, and diminishing polar ice. While 2025’s surface temperatures were marginally lower than the previous year, the report emphasizes that the planet continues a “run of exceptionally high temperatures,” signaling a long-term shift rather than a short-term anomaly. Sea-ice levels in both the Antarctic and Arctic have remained near historic lows, reinforcing concerns about the vulnerability of polar ecosystems and global weather patterns.
Climate scientists warn that these trends indicate the planet is entering a new era of sustained warming. Mandy Freund, a climate researcher at the University of Melbourne, Australia, stresses that “the speed at which temperatures are rising, the ocean is heating up, and glacial ice mass is melting is concerning.” Sarah Perkins-Kirkpatrick, of the Australian National University in Canberra, echoes these concerns, noting that “the past three years have seen a step change in temperature that could only be a result of climate change,” underscoring the persistent nature of this warming trend.
For the first time, the WMO report incorporates a measurement of Earth’s energy imbalance (EEI), an indicator that captures the accumulation of heat in the atmosphere and oceans. EEI, the difference between incoming solar energy and the energy radiated back into space, reached its highest recorded level since observations began in 1960. A positive EEI indicates that more heat is trapped on Earth than is being released, a direct consequence of rising greenhouse-gas concentrations.
Thomas Mortlock, a climate analyst at UNSW Sydney, says the inclusion of EEI is significant because traditional coverage of climate change tends to focus on surface temperatures, which account for only about 1% of excess planetary heat. “More than 91% of all of the excess heat that has been received by the Earth since the 1970s has been absorbed in the oceans,” Mortlock explains. By tracking EEI, scientists gain a more accurate picture of the long-term severity of global warming and the energy being stored within the Earth system, beyond short-term fluctuations caused by phenomena like La Niña events or volcanic eruptions.
The report also highlights record greenhouse-gas concentrations. Atmospheric carbon dioxide reached 423.9 parts per million in 2024—the highest level in two million years—equating to roughly 3,306 gigatons of CO2 held in the atmosphere. Methane and nitrous oxide concentrations also hit record highs, continuing a trend that exceeds natural variability by a wide margin. Ice core records from Antarctica show that over the past 800,000 years, CO2 levels fluctuated between 150 and 300 parts per million, meaning current levels are unprecedented in the geological record. Mortlock notes, “We are now far outside the bounds of natural climate variability,” emphasizing the human-driven nature of recent changes.
The consequences of this warming extend beyond temperature records. Rising heat and altered rainfall patterns have exacerbated the spread of vector-borne diseases. Dengue fever, for example, has emerged as the world’s fastest-growing mosquito-borne viral disease, spreading to regions previously less affected due to warming climates. Perkins-Kirkpatrick notes that adaptation measures are now essential. Communities must prepare for more extreme weather, upgrade infrastructure to withstand heat waves, and strengthen public health systems to manage climate-related health risks.
Ocean warming, another critical indicator, is increasingly alarming. Oceans absorb the vast majority of excess heat, driving changes in currents, weather patterns, and marine ecosystems. Freund warns that even modest increases in ocean temperatures can disrupt fisheries, amplify storms, and accelerate ice sheet melting, which contributes to rising sea levels. “The oceans are storing the heat that we don’t see on land, but the impacts will inevitably reach communities worldwide,” she says.
Scientists emphasize that mitigating further warming requires urgent reductions in greenhouse-gas emissions. While some level of warming is already locked in, slowing future temperature increases will help limit the most severe consequences of climate change. “Reducing emissions today is critical to ensure the warming we cannot reverse does not spiral out of control,” says Perkins-Kirkpatrick.
The WMO report signals an urgent need for both mitigation and adaptation strategies. Urban planners, health authorities, and policymakers must now account for higher baseline temperatures, more frequent extreme weather events, and climate-driven shifts in disease prevalence. International coordination remains crucial, as the energy imbalance and greenhouse-gas accumulation are global phenomena, requiring cross-border solutions and ambitious climate targets.
Experts suggest that public communication about climate change should expand beyond surface temperature records. The inclusion of EEI in the WMO report, covered in part by publications such as Nature, provides a clearer understanding of the full scope of heat accumulation and planetary stress. By framing global warming in terms of energy imbalance, scientists hope to convey both the magnitude and urgency of the crisis.
As the planet experiences what researchers describe as a period of “extraordinary warmth,” the report warns that the coming decades may see even higher baseline temperatures, further ice loss, and amplified impacts on human health and natural systems. The WMO’s findings serve as a stark reminder that the climate crisis is no longer a distant threat but an unfolding reality, demanding immediate and sustained action across all sectors of society.
The world now faces a pivotal moment: the scientific consensus is clear, the data is compelling, and the consequences of inaction are increasingly visible. From rising seas and heatwaves to spreading diseases and disrupted ecosystems, humanity must confront a planet whose energy balance is shifting toward a hotter, more unpredictable future. The WMO report, alongside coverage in journals such as Nature, underscores the urgency of global climate action, highlighting that the window to prevent the most catastrophic outcomes is rapidly closing.
