Professor Andrew Watson - Stories of Change

Stories of Change Project

Professor Andy Watson interview

Key

RH      = Roger Harrabin, Interviewer

AW      = Professor Andy Watson, Royal Society Research Professor, Exeter University Participant

RH          This is Andy Watson.  Andy, tell me, you’ve seen Nic Lewis, what’s nice about it? I’m thinking in terms of the previous episodes with climate sceptics, ideologically driven?

AW:        Nic Lewis is a little bit different to the climate sceptics that we often end by having dialogue with. He is prepared to put his ideas and his papers into peer-review and that means that instead of having an ideologically driven contest, which you can’t really get to any kind of truth with, he’s joining the scientific debate, so you can talk to this guy, you know what he really thinks ‘cause he’s written it down in detailed papers, so this is quite different to the rather sterile debate with political ideologists.

RH:         A bit of a breath of fresh air from that point of view.

AW:        Yes. And one can engage with him and I don’t think that his study is the best study that’s ever been done on the climate sensitivity but I do understand what he’s done and how he gets to his conclusions.

RH:         Why do you think his numbers are still too low?

AW:        Because what he’s doing is using the observational record and trying to guide simple models with that observational record from the recent past, when CO₂ has been going up. Now that doesn’t take, I think, take into account the fact that there is probably considerably more change to come. In other words some of the feedbacks which tend to make the climate sensitivity higher are relatively slow to come into effect.

RH:         So what you mean is that we have already changed the climate of the future, not just of now, because of the CO₂ that we’ve already put in the atmosphere?

AW:        Yes. We’re committed to a change in the future and there’s a lag between you’re putting the carbon dioxide in the atmosphere and the fullest effects of that change being apparent in the climate, and one can only take into account some of that lag by looking at the observational record up to date.

RH:         Right. So perhaps you can tell me about what the IPCC says and why you think it’s more likely to be that?

AW:        The climate sensitivity as quoted by the IPCC has not changed very much ever since the IPCC started writing reports back in 1991. It remains around 3 degrees centigrade for a doubling of carbon dioxide. That’s the best estimate but with a wide range. It could be conceivably as low as 1.5 degrees, it could be as high as, well  in the fourth report they were quoting up to nearly 6 degrees centigrade, so somewhere in those levels.  Now it’s quite interesting that the lower bound of the IPCC is pretty close to the kind of number that Nic Lewis gives for his best estimate, so in a certain sense they’re not absolutely poles apart.

RH:         The sceptics to an extent have joined the mainstream?

AW:        They’re on the same page, if that page is relatively large, yes, they’re on the same page.

RH:         Is there a risk in focussing our attention on climate sensitivity, the doubling of CO₂, because I don’t know many people who think we’ll actually stop at doubling CO₂. Most people I know in the scientific world think we’ll go much beyond that.

AW:        There is a risk. It simplifies and oversimplifies the debate, because if you concentrate, for example, on the average rise in temperature, that’s not actually very significant. It’s not what causes the climate impacts, which is more the change in extremes, changes in things other than temperature such as precipitation, floods and droughts etc. So yeah, it oversimplifies it. Also, as you say, we don’t expect most people expect that eventually we’re going to go to more than double CO₂.

<End of Interview>