Hm, I feel like this is way less sinister than it sounds. From what I know of his prior reputation, Will Happer has long made his position on climate change clear, so it's not like he changed his mind when people offered him a big pile of money.
If you already believe something and someone is going to give you money to promote your views, why on earth would you say no?
If you already believe something and someone is going to give you money to promote your views, why on earth would you say no?