At the conclusion of his Revelle Medal acceptance speech Pieter Tans well captures the ethical need for those who study atmospheric carbon contamination to speak out
As climate scientists we now find ourselves in the situation that our subject is widely understood to be so relevant to society that many powerful interest groups feel threatened. Thus, we are facing a well-organized and well-funded campaign attacking our science and our integrity, spreading confusion and disinformation. This is not surprising, as mitigating climate change goes to the core of our energy supply system and the broader economic system. Human-made climate change demonstrates that we cannot continue business as usual. Should we ignore the deliberate lies and manipulations we face and stick purely with the science, hoping that sound judgment and compassion will eventually prevail? We are scientists, but we are also citizens. It is our civic responsibility to redouble our efforts to convey to the public clearly the urgency and the essence of the climate change problem. The kind of world we leave to our children and grandchildren depends on it. It will have to be a world that has as one of its guiding principles a Sanskrit prayer that was used as a dedication in the above mentioned 1972 book: “Oh Mother Earth, ocean-girdled and mountain-breasted, pardon me for trampling on you.”Earlier at Climate Science Watch and Climate Progress, but IEHO they both buried the lead. This is but the latest instance of a distinguished scientist concluding that he can no longer stay hidden on the sideline but has a moral responsibility to speak out in public. It is a signal failure of the denialists that they have created the backlash. But they can't help themselves, the poor dears. It is also, as Ethon pointed out, a stick in the eye for the Honest Broker.