So says Science. But for the life of me I can’t see why. Hat tip: CB and (!) LM.
Its based on preliminary results from ACEX. Which says… drilling revealed that the latest Paleocene to earliest Eocene boundary interval, well known as the early Eocene Thermal Maximum (EETM), was recovered. During the EETM, the Arctic Ocean was subtropical with warm surface ocean temperatures. I’m not quite sure why this is supposed to be a problem for the modellers though.
Very few people run climate models back then; I don’t suppose the boundary condtions are known very well. So quite why the conclusion has climate modelers stumped I’m unsure. On the contrary, I would have though a bit of new data on what condtions were actually like then might be helpful.