Check this out: Patrick Moore

"Patrick Moore is one of the early members of Greenpeace. He left in the 1980s after he felt the organization had lost its way. In the last few years, he has come out in favor of GMOs and changed his stance on such issues as nuclear power.
As proof the environmental movement is more like a cult rather than an unemotional, rational thinking movement, his former ideological comrades and their fellow travelers take every opportunity to try and discredit him and his reformed views. He left the fold and started thinking independently, which is heresy to the cult." - The Progressive Contrarian