Data-based analysis confirms: Paris Agreement temperature limits increasingly out of reach

According to an international team led by physicists Josef Ludescher from PIK and Armin Bunde from Justus Liebig University Giessen, the 1.5 °C threshold could be crossed as early as 2025, and is very likely to be exceeded by 2040. For the well below 2 °C limit, the researchers estimate a 20% probability of exceeding the threshold as early as 2047 and an 80%  chance of doing so by 2069.

The study, published in Communications Earth & Environment, is based entirely on observational temperature data. It accounts for the climate system’s tendency to remain in unusually warm or cold phases over longer periods. This allowed the team to separate the human-made global warming trend from natural variations in the climate and to calculate probabilities for crossing the Paris thresholds. While climate models simulate the Earth system’s physical processes, this study provides an independent confirmation based on real-world measurements. This alignment highlights the urgent need for overshoot management, the researchers argue - measures to limit temporary overshoot of climate targets and return below critical thresholds as quickly as possible. The 1.5 °C limit is now seen as barely within reach. But the well below 2 °C limit could still be achieved, through deep global emissions cuts and protection of natural carbon sinks.