The urgency of climate action has grown as global warming edges closer to limits set by international agreements. A new study provides a clear and reliable record of rising global temperatures, underscoring how close the world is to crossing the Paris Agreement’s lower safety limit. This record highlights the need for straightforward definitions that make it easier to track progress toward international climate goals.
Professor Gottfried Kirchengast and Moritz Pichler from the University of Graz created a new record of global surface temperatures stretching from the mid-1800s to today, with projections that look ahead into the next decade. Their work, published in Communications Earth & Environment, offers an updated picture of climate change, showing that the latest yearly average temperatures have already climbed beyond the lower guardrail set by the Paris Agreement when compared to pre-industrial times. Although the long-term global warming expressed by the average over two decades remains just under this line, the study concludes that it will likely be crossed before this decade ends.
Professor Kirchengast and Pichler developed what they call the “ClimTrace global surface temperature record,” a carefully assembled dataset designed to follow the methods used by the Intergovernmental Panel on Climate Change, the United Nations’ main scientific body on climate issues, while making the results easier to understand. By adjusting how land and ocean measurements are combined, they found clear evidence of faster warming in recent decades. Professor Kirchengast explained, “The twenty-year average still stayed below the lower Paris limit but is set to cross this threshold within just a few years.”
This record provides not just numbers, but also context for how climate limits are defined and measured. For example, while the most recent annual average already shows that warming has moved beyond the lower Paris target, the longer-term average across multiple years shows that sustained warming at this level is still just around the corner. These insights are vital because international climate policy relies on long-term averages rather than single hot years.
The study also suggests a clearer way to describe progress toward the Paris Agreement. It introduces four categories: the one and a half degree target, meaning still in line with the main Paris goal, well below two degrees, meaning slightly above the lower guardrail but with a sufficiently limited overshoot in order to enable a return to below this guardrail clearly before 2100, risky below two degrees, meaning getting close to two, and exceedance of two degrees, meaning beyond two. The researchers argue this simple system will make it easier for decision-makers, legal experts, and the public to judge whether the world is keeping its commitments.
Beyond technical improvements, the work carries important implications for global action. The clarity it provides can support the United Nations’ global stocktake process, which is the formal review of worldwide climate progress, and serve as a reference for climate-related laws and court cases. Professor Kirchengast noted, “Such clear quantification can help spur climate action in the policy and legal domains and further standardization can help to also underpin the Paris Agreement’s global stocktake process.”
The larger message is sobering: unless greenhouse gas emissions, meaning gases like carbon dioxide and methane that trap heat in the atmosphere, are rapidly reduced, the world will soon move past the safer Paris limit and enter more dangerous territory. Projections suggest that within little more than a decade, without stronger action, global warming could move firmly into the range considered risky, with longer-term scenarios pointing toward even greater exceedance later in the century.
Adding to this urgency, the University of Graz team has now released their first forecast for the current year before it has ended. Their calculations show that 2025 will already be extremely close to the lower Paris limit, reinforcing how little time remains to prevent further warming. Looking ahead, they project that the world is almost certain to cross the one and a half degree threshold before 2030 unless emissions are cut drastically. This marks a turning point, as the focus shifts not only to historical records but also to forward-looking forecasts that confirm just how narrow the remaining window of opportunity has become.
© Uni Graz/Wegener Center
Professor Kirchengast added, “Clear quantification of the Paris goals can help spur climate action in the policy and legal domains. Our results show that this is more urgent than ever.”
Journal Reference
Kirchengast G., Pichler M. “A traceable global warming record and clarity for the 1.5 °C and well-below-2 °C goals.” Communications Earth & Environment, 2025. DOI: https://doi.org/10.1038/s43247-025-02368-0
Backinfos for feature article on the paper https://www.nature.com/articles/s43247-025-02368-0
About the Authors
Professor Gottfried Kirchengast is Lead Scientist and Professor of Geophysics (Alfred Wegener’s Chair) at the University of Graz, Honorary Professor at the National Space Science Center (NSSC) of the Chinese Academy of Sciences, and Member of the Austrian Academy of Sciences. In 2023 he received, after a range of other prizes and awards, the Badge of Honor of the State of Styria for Science, Research and the Arts, the highest state recognition for lifetime achievements in science for society. He is Founding Director of the Wegener Center for Climate and Global Change of the University of Graz, Founding Speaker of its Field of Excellence Climate Change as well as Speaker for its Earth Observation and Climate Strategies, and Representative of Science in the Austrian National Climate Committee, among many other lead functions. He (co-)authored more than 400 publications, supervised more than 40 PhD students, and made as well as continues to make pioneering research and international leadership contributions in the fields of Earth observation and climate science.
Moritz Pichler holds a Master of Science in Physics with a specialisation in atmospheric physics and climate change. Since 2023, he has been a researcher and PhD student in the Graz Climate Change Indicators Team at the Wegener Center for Climate and Global Change of the University of Graz, where his work focuses on quantifying the physical links between greenhouse gas emissions and global warming. Recently, he has been preoccupied with the deceptively simple yet surprisingly complex question of what “surface temperature” actually means.
