H/T Messenger for this podcast by Professor Murray Salby of Macquarie University. Salby looks to be pretty mainstream, having published with Susan Solomon and Martin Juckes among others. The message appears to be that much of the rise in atmospheric carbon dioxide may be natural and caused by non-anthropogenic warming.
Andrew Bolt summarises the talk here, noting Salby's comments that anyone who thinks global warming science is settled is "living in Fantasia".