The IPCC hasn't said it in an official report. But Jim Hansen has said: "Barack Obama has only four years to save the world. That is the stark assessment of Na

The IPCC hasn't said it in an official report. But Jim Hansen has said: "Barack Obama has only four years to save the world. That is the stark assessment of Nasa scientist and leading climate expert Jim Hansen who last week warned only urgent action by the new president could halt the devastating climate change that now threatens Earth. Crucially, that action will have to be taken within Obama's first administration, he added." https://www.theguardian.com/environment/2009/jan/18/jim-hansen-obama https://www.theguardian.com/environment/2009/jan/18/jim-hans... The IPCC chairman, Rajendra Pachauri, an engineer and economist from India, acknowledged the new trajectory. "If there's no action before 2012, that's too late," Pachauri said. "What we do in the next two to three years will determine our future. This is the defining moment." from: https://www.nytimes.com/2007/11/18/world/europe/18iht-climate.2.8378031.html?pagewanted=all https://www.nytimes.com/2007/11/18/world/europe/18iht-climat... There are a few lists around the place of people saying similar things. Those are just I could find easily without too much bother. Edited to put the Hansen statement in.