Who exactly is Michael Shellenberger and what is his game? It's pretty clear that he is not a trained scientist or a journalist. What qualifies him to speak for

Who exactly is Michael Shellenberger and what is his game? It's pretty clear that he is not a trained scientist or a journalist. What qualifies him to speak for those of us who are concerned about climate change and issue an apology on our behalf? Seems rather grandiose to me. I'm thinking pundit with political ambitions.