When a mainstream climate scientist comes up with some findings that go against the narrative of impending catastrophe they usually feel obliged (or are obliged by others) to take steps to distance themselves from the implications - hiding them, issuing declarations of orthodoxy, or saying something rude about dissenters.
We saw something of this in Bjorn Stevens' recent paper on aerosol forcing, with the implications for climate sensitivity left to one side. Yesterday, however, Stevens went futher and issued a declaration of his absolute global warming faith.
Many scientists (myself included) believe that a warming of more than 2ºC from a doubling of the concentration of atmospheric carbon dioxide is consistent with both my new study and our best understanding. Some insight into our reasoning can be found in a number of excellent blogs reporting on a workshop on Earth’s Climate Sensitivities, which I co-organized just last week, e.g., http://www.realclimate.org/index.php/archives/2015/04/reflections-on-ringberg
So contrary to some reports that have appeared in the media, anthropogenic climate change is not called into question by my study. I continue to believe that warming of Earth’s surface temperatures from rising concentrations of greenhouse gases carries risks that society must take seriously, even if we are lucky and (as my work seems to suggest) the most catastrophic warming scenarios are a bit less likely.
The full statement is here.