Can Jeff Sessions Be a Climate Denier and Lawfully Serve as Attorney General?

President-elect Trump has nominated Senator Jeff Sessions to be the nation's top lawyer — the attorney general of the United States. The Senate confirmation hearings for Sessions begin today. Hopefully someone will ask Sessions whether he can reconcile his denial of climate science with his obligations under the Rules of Professional Conduct governing all attorneys, even the top one. 
Much has been written about Sessions's checkered past — the racially insensitive statements that derailed his 1986 nomination to a federal judgeship, his hostility to immigrants' rights, and his blanket denial of climate science. The Sierra Club stands in solidarity with the vast number of people who legitimately feel threatened by a Sessions appointment. As a leading NGO fighting the threat of climate catastrophe, we find ourselves particularly chagrined by Sessions's refusal to acknowledge the facts of climate science. We question whether Sessions can serve as attorney feneral while continuing to misrepresent the facts. We don't think he can.
The American Bar Association has promulgated a set of Model Rules of Professional Conduct that govern attorney behavior with clients, tribunals, and third parties. These rules are followed by the various state bar overseers and dictate how lawyers must carry out their professional duties. One central theme in the model rules is the principle of candor and truthfulness.  For example, Model Rule 3.1 states that "A lawyer shall not bring or defend a proceeding, or assert or controvert an issue therein, unless there is a basis in law and fact for doing so that is not frivolous." Similarly, Model Rule 3.3 states that "A lawyer shall not knowingly make a false statement of fact or law to a tribunal."
Sessions has been cited in various contexts as denying that carbon dioxide is a pollutant or that temperature increases have occurred as predicted by the science.  If he becomes the nation's top litigator, can he continue to make these outlandish claims and still comply with his professional obligations? We don't think so. Imagine, for example, that the Trump administration or industry attempts to reverse the "endangerment finding" — the EPA decision that established the threat posed by greenhouse gas pollution. Imagine Sessions or one of his deputies arguing that the science does not support the finding. Would that not be a false or frivolous statement, in violation of the professional rules?
As a practicing litigator and strong proponent of the First Amendment, I am aware of the tension between creative advocacy and misinformation. In my view, Sessions's brand of climate denial falls squarely on the latter side — it is an extension of the misinformation propagated by the fossil fuel industries. And while the Koch brothers and their ilk may get away with such propaganda, the U.S. attorney general cannot. He must be truthful and fair, and must not misrepresent climate science to the courts or the public.