Scientists disagree about whether humans are warming the planet

What actually happened

Watch the language harden across the reports, because that is the story. In 1995 the IPCC said the balance of evidence suggests a discernible human influence. In 2001, likely. In 2007, very likely. In 2013, extremely likely. In 2021, unequivocal, stated as fact rather than probability.

The scientific consensus was never as split as classrooms implied. Naomi Oreskes' 2004 survey of the peer-reviewed literature found no papers disputing anthropogenic warming; Cook and colleagues in 2013 found 97 percent agreement among abstracts stating a position; a 2021 update put it above 99 percent. The public sense of an open debate was manufactured, and the documentary record of that campaign is now itself a subject of historical research, including Oreskes and Conway's Merchants of Doubt.

What is genuinely uncertain, and should be taught as uncertain, is sensitivity at the tails, regional effects, ice sheet dynamics, and tipping point thresholds. Those are live and hard. Whether the warming is human-caused is not among them, and has not been for a long time, whatever your Earth science teacher's textbook said.