Here are three sources of commentary that show why the paper is definitely not the end of concern about climate change.
* James Annan, whose own work also argues against the possibility of really high climate sensitivity, still suspects that the sensitivity indicated by this paper may be an underestimate.
* Skeptical Science has an excellent article on the paper, and notes (as have some others around the place) that the "glass half empty" way of looking at it is that even if it shows lower temperature sensitivity, it can be taken to mean that modest changes in CO2 seem to be capable of making dramatic climate changes on land:
...Schmittner et al. have assumed that the difference between a glacial maximum and interglacial temperature is a mere 2.6°C. The global average surface temperature has already warmed 0.8°C over the past century. During the LGM, the surface was covered with huge ice sheets, plant life was different, and sea levels were 120 meters lower. As Schmittner notes:
* One of the co-authors gives a detailed interview at Planet 3, and if very specific about saying that they do not feel they have "proved" that really high climate sensitivity outcomes are not possible."Very small changes in temperature cause huge changes in certain regions, so even if we get a smaller temperature rise than we expected, the knock-on effects would still be severe."