The World May Have Already Surpassed the 1.5C Global Warming Limit

The goal of limiting global warming to 1.5 degrees Celsius, as outlined in the Paris Agreement, may already be out of reach, according to two new studies in Nature Climate Change. While past projections estimated that temperatures would cross this threshold in the 2030s, 2024 marked the first full year above 1.5 degrees Celsius, raising concerns that a long-term breach is already underway.

Unlike single-year temperature spikes, the Paris Agreement’s 1.5 degrees Celsius target is based on a 20-year average, making it difficult to determine in real-time whether the threshold has been surpassed. However, climate models used by researchers, including Alex Cannon of Environment and Climate Change Canada and Emanuele Bevacqua of Germany’s Helmholtz Centre, indicate that sustained warming above 1.5 degrees Celsius is now likely—or even virtually certain.

The implications are severe, as every fraction of a degree above 1.5 degrees Celsius increases the risk of extreme weather events, rising sea levels, and ecosystem disruptions. While scientists stress that drastic emissions reductions can still slow further warming, political challenges—including policies that expand fossil fuel use—threaten meaningful action. Small island nations, which face existential risks from rising seas, have long advocated for keeping global temperatures below this threshold.

With carbon emissions at record highs, researchers warn that time is running out to reverse course. While the exact moment of breaching 1.5 degrees Celsius remains unclear, the message from climate scientists is not: urgent action is needed now to mitigate the worst effects of climate change.