So the first set of them were greenhouse gas concentration pathways, so modeling included feedbacks like ice-albedo, but not ones which resulted in additional fossil fuel use.
Current approaches are shared socioeconomic pathways rather than representative concentration pathways.
Still not perfect because people won’t actually follow any such path exactly; it’s a lot harder to predict human behavior than physics
So the first set of them were greenhouse gas concentration pathways, so modeling included feedbacks like ice-albedo, but not ones which resulted in additional fossil fuel use.
Current approaches are shared socioeconomic pathways rather than representative concentration pathways.
Still not perfect because people won’t actually follow any such path exactly; it’s a lot harder to predict human behavior than physics