In May the Sierra Club opted to install a community organizer as her president, from Politico :
The Sierra Club, the nation’s biggest environmental group, is out to prove that the green movement isn’t just for well-to-do white people.
The 123-year-old organization just elected its first black president. Its board condemned racial profiling in Ferguson, Missouri. Environmental justice has become one of its core campaigns.
That’s a major shift for a political and social movement long viewed as the domain of affluent white activists, and it’s been decades in the making.
Aaron Mair, who became the first black president of the Sierra Club’s board of directors earlier this month, said the group is dedicated to becoming more inclusive.
Sierra Club may have thought they were solving their perceived diversity problem. Maybe they did, but in the process they created a competency problem by installing a nitwit as their president. When matched up against trial lawyers, community organizers don’t tend to do well, video:
Summary of the exchange, Breitbart 
I find it amusing that Mr. Mair declares that the preponderance of evidence supports the theory of anthropogenic global warming(AGW). Therefore the question of AGW is closed. It appears that Mr. Mair failed to study any real science. Preponderance of the evidence means more evidence for than against, but not conclusive. So the Sierra Club’s is that whilet the evidence for AGW is not conclusive, yet the theory of AGW must be accepted. Wow.
When can we expect Mr. Mair’s resignation from the Sierra Club?