The scientists are too optimistic, frankly. Nobody predicted air and sea surface temperatures to decouple from historical means in 2024 and reach a sustained increase of over +1.5C from historical baselines, but it happened. I think that says we've got no fucking idea how fast this is going to go now that it's going or how far.
Those 6% who think we will contain heating to 1.5C are already provably wrong and yet are still saying it. One out of every 20 climate scientists is so utterly blinkered that they can't look at the current actual data and go "shit guess I was wrong about everything." That doesn't speak well of the average either.