Transcript of debate on climate change between the Hudson Institute’s Dennis Avery concerning his new book, coauthored with Dr. Fred Singer, and climate change campaigner Mark Linus.

(audio available here: http://www.bbc.co.uk/radio4/today/listenagain/ram/today5_climate_20070118.ram, for those who avoid RealPlayer here's a link to Real Alternative)

BBC Host: A sort of related item now, if we’re talking about our climate: A new book says that global warming isn’t caused by human beings, it’s just that the earth has a natural 1,500 year warming cycle. One of the authors of Unstoppable Global Warming: Every 1,500 years is the agricultural economist Dennis Avery from the Hudson Institute, he’s here. Also on the line is Mark Linus, the writer and climate change campaigner.

Gentlemen, Good morning. Mr. Avery, please explain why you think global warming is not caused by human beings.

Avery: About 20 years ago we brought up the first long ice core from Greenland. And it showed the 100,000 year ice age cycle. But to our great surprise it also showed a moderate 1,500-year cycle that seemed to be linked to the sun. And 4 years later we brought up another longer ice core in the Antarctic and that showed the 1,500-year cycle. And we’ve since found it in 300 peer-reviewed studies of sea-bed sediments, cave stalagmites, pollen fossils all over the world. And yet we don’t talk about this. We assume that any change in temperature is our fault.

Host: Are you saying then that you’re not alone in your views. Because your views do, of course, run counter to the majority of other scientists who do attribute it to our abuse of the environment – CO2 emissions from humanity.

Avery: We cite in the book 100 studies of peer-reviewed science finding the 1,500-year cycle in physical evidence. We could have cited 300, probably 1,500 science authors.

Host: Mark Linus, what do you make of that? Do you think that there could be any, anything to look at here, anything to examine further?

Linus: I strongly doubt it. It’s sort of intriguing to hear Dennis Avery sounding like he’s a paleoclimatologist whose been tramping around the ice cap in Greenland, whereas in fact he’s an agricultural economist based at the Hudson Institute, which is on the far-right of think tanks even by American standards. And, um, so I think what’s going on here is the standard sort of global warming denier attempt to blind us with pseudoscience, if you like. They cherry pick what’s out there in the scientific literature and try and create an argument which simply doesn’t sustain itself. I mean, I would invoke the principal, the scientific principal of Occam’s razor, which is that you don’t need to invoke an alternative explanation when a perfectly satisfactory one exists, and that is that the build-up of greenhouse gases caused by humans is warming the planet outside what has been experienced for, uh, now for tens of thousands of years. And the latest scientific projections – and I mean scientific projections rather than pseudoscientific ones – suggest that the northern polar ice cap might have disappeared as soon as 2040. And that will leave the Arctic ocean ice-free for the first time in 3 million years. So talk of one thousand five hundred year solar cycles is neither here nor there. And it’s not worth looking …

Avery: It’s another scientific principal that if you have an observation it outranks a theory. And you’re working from a theory which has absolutely no demonstrated reality. We have no knowledge that human-emitted CO2 has aggravated the natural 1,500-year climate cycle, which has been documented all over the world and published in most of the major climate journals.

Host: Well, Mr. Linus, how would you respond to that? Is there evidence?

Linus: Well I think the thing to do is if you want to look at this book, do so by all means. But … (interrupted by host)

Host: But is there evidence, though? Because you had a challenge there.

Linus: No, but look, what’s important is to look at …

Avery: He has computer models.

Linus: … look at what the scientific consensus is …

Avery: He has computer models.

Host: Ok, Mr. Avery.

Linus: In three weeks time the intergovernmental panel on climate change will be issuing the first of its major landmark reports for six weeks. So either you can listen to the wild-eyed rantings of right-wing economists who happen to be funded by Exxon-Mobile – and I’m afraid there’s evidence of that, too – or you can listen to the sort of considered opinion of 2,000 of the best climate change experts in the world. It’s up to you.

Host: Do you think, Mr. Linus, that there is room for other views like this though, or are you saying that this should be just dismissed out of hand?

Linus: No, nothing should be dismissed out of hand and that’s not the way science works. Science should be held as a debate. But, uh, the way the skeptics and global warming deniers work is that they simply have to confuse the public. If listeners to this item come out confused and unsure as to whether or not it is important to cut their greenhouse gas …

Avery: Why are you not welcoming the debate?

Linus: … emissions, then Dennis Avery will have done his job

Avery: Why are you not welcoming the debate?

Linus: The reason why …

Host: One at a time, please.

Avery: It’s all ad hominem!

Host: Hold on, let Mark Linus finish his point and then you can come back, Mr. Avery.

Linus: I I I mean, I am very familiar with the scientific literature and you won’t find any of this stuff about one thousand five hundred year solar cycles in it because it simply is not publishable because it would be laughed out of court by any of the reputable scientific journals. So you need to look at the peer-reviewed science and I think that’s where you need to get your evidence from.

Host: Mr. Avery.

Avery: That, sir, is a bald-faced lie. As I told you earlier, in the book I cite 100 different scientific studies, most of them published in the journals Nature or Science or Quaternary Letters Review. And …

Linus: It’s Quaternary Science Review, actually, but go on.

Avery: You’re absolutely correct. I’m sorry I stumbled. But for you to say that there is no science, … uh, it is simply … beggars the imagination.

Host: Alright. We have to leave it there. We’ll let the listeners make up their own minds, although they may be confused after that as Mark Linus said. Dennis Avery, Mark Linus, thank you very much.