ABC: MARK COLVIN: Two of the world’s most influential climate sceptics appear to have had a change of heart. The Danish academic Bjorn Lomborg wrote a book in 2001 called The Skeptical Environmentalist which said climate change wasn’t that serious and we couldn’t and shouldn’t do much about it. But now he says it’s undoubtedly one of the chief concerns facing the world today. Michael Hanlon the formerly ultra-sceptic science editor of Britain’s two-million-copies-a-day Daily Mail has also …