Here is the Australian National Press Club debate between Christopher Monckton v Richard Denniss on July 19, 2011. I would suggest you skip the Denniss presentation and go directly to Monckton at 12:40 in the video:
The debate is over whether it is prudent to put in place a carbon tax to rein in the use of fossil fuels. The Monckton response is that the cost of reining is far exceeds the benefit. And on top of that, it isn't clear that the science can identify much real warming and Monckton makes that point at 25:00 into the video.