Bloomberg - (archived: https://archive.ph/ZGUqM ) It’s ‘Virtually Certain’ the World Has Already Breached 1.5C

Two new studies reveal that last year’s record heat is a sign that burning fossil fuels has already pushed the climate past a key threshold.

By Kendra Pierre-Louis
February 10, 2025 at 4:00 PM UTC

The world may have already missed its chance to limit global warming to 1.5C, according to two new studies in Nature Climate Change.

The Paris Agreement was inked in 2015, with 196 countries agreeing to rein in greenhouse gas emissions to keep the global average temperature increase to “well below” 2C and ideally cap it at 1.5C compared to pre-industrial times. The new analyses show the world will surpass the latter, underscoring the urgent need to cut carbon emissions.

“Every increment of warming above 1.5 degrees Celsius means worse extremes,” said Alex Cannon, a research scientist with Environment and Climate Change Canada, and author of one of the studies. “If we continue warming the atmosphere, consequences will be greater.”

In 2024, global temperatures reached 1.5C for the entire year, the first time it’s happened in recorded history. It was a stark departure from previous projections: The Intergovernmental Panel on Climate Change report published just a year earlier suggested that temperatures would reach 1.5°C in the early 2030s if emissions weren’t cut. The breach left scientists wondering, “is this a sign? Are these short-term exceedances above that level indicative of us actually reaching that target sooner than we expected?” said Cannon.

The reason for those questions is because the Paris Agreement’s 1.5C threshold isn’t focused on daily or even yearly temperatures. Instead, it’s based on a 20-year retrospective average, which means the world won’t know it’s hit 1.5C until after the fact. The two new studies attempt to get around that by using climate models to look ahead based on current data to see if we’ve already entered a 20-year period above 1.5C.

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