A pioneering study reveals that global temperatures have already exceeded the 1.5°C warming threshold and could cross the 2°C mark as early as this decade. This alarming conclusion is based on temperature data obtained from marine sponge skeletons, indicating that global climate change is far more advanced than previously thought. Man-made greenhouse gas emissions are the main cause of global warming, and accurate information on its extent is crucial for assessing the likelihood of extreme weather events in the short term, and for measuring progress in reducing emissions. Unlike traditional methods based on sea surface temperature records dating back some 180 years, this research examined 300 years of records preserved in the skeletons of long-lived sea sponges from the Eastern Caribbean, using variations in strontium quantity as an indicator of changes in seawater temperature. The results, published in Nature Climate Change, suggest that the 1.5°C limit set by the 2015 Paris Agreement has already been exceeded, probably reaching at least 1.7°C of warming since pre-industrial times. This discovery is particularly worrying, and calls into question the goal of keeping global warming below 2°C, a target which now looks set to be exceeded well ahead of schedule. The revised estimates indicate that climate change is at a more advanced stage than previously thought, underlining the urgent need for immediate action to reduce greenhouse gas emissions and mitigate the impacts of global warming.
