There's a style of debating where you split into two teams to argue for and against a proposition and it doesn't really matter what you believe, the winners are the ones making the best argument. For instance the Cambridge Union https://cus.org/members/debating/what-debating

Your friends points sound like he's making arguments against warming because that's the team he's on as it were. There's a bit of a human tendency to split into warring teams rather than all pull together. Blame evolution perhaps.