Geoengineering: can man mimic volcanoes?

Interviewer: Sam Walter (Interviewer, Ideas Lab)
Guest: Dr Francis Pope
Recorded: 15/10/2013
Broadcast: 03/03/2014

Intro VO: Welcome to the Ideas Lab Predictor Podcast from the University of Birmingham. In each edition we hear from an expert in a different field, who gives us insider information on key trends, upcoming events, and what they think the near future holds.

Sam: We’re here today with Dr Francis Pope who is a Lecturer and a Birmingham Fellow here at the University of Birmingham. Hello, Francis.  

Francis: Hello, thanks for having me. 

Sam: So, can you tell us a bit more about what you do here at the University of Birmingham?

Francis: OK, so my research is predominantly focused on aerosol microphysics and chemistry. Aerosols are small particles, which reside in the atmosphere. Now what I focus on is two of their applications, one of which I’ll talk about today, which is geo-engineering. The other thing I’m interested in is bio-aerosols but maybe we’ll leave that for another day. 

Sam: So what is geo-engineering?

Francis: OK, so geo-engineering is this idea that to counteracts the negative impacts of climate change. We can do something to the earth’s system to make it cooler or to reduce the radiation, so there’s lots of different options and we should be careful to make a generalisation, or a broad generalisation, between the two different types of geo-engineering to start off with. So there’s something called carbon dioxide removal which as the name suggests, this is processes which pull carbon dioxide out of the atmosphere, so this might be something like planting more trees or sucking CO² into machines which turn it into something solid, something like that. And so that’s the less controversial side. The more controversial side is something called solar radiation management and this, rather than removing the CO², is trying to reduce the temperature by removing some of the radiation coming down and so essentially all these techniques, one way or another, acts like a mirror. So we can think about if we painted the whole world white it would be more reflective and would lose a lot of the radiation back out to space and that would cool it down. Not very practical but you can see where I’m going. And so the particular version of solar radiation management that I’m interested in - and this is because it seems to be the most likely to succeed at this moment in time. Something called the stratospheric conjection of aerosols and this mimics volcanoes in essence, big stratospheric volcanoes. So the last big volcano was Mount Pinatubo in the Philippines in 91 and this injected I think it was about 30 megatons of material into the stratosphere and so again these are these small particles which I talked about earlier and these reflect sunlight and so what you saw after Pinatubo was for about one or two years there was actually a definite degree of cooling. So about half a degree of cooling. So we know from this natural analogue that the technique should work. Now the challenge is can we now make this technique work in the atmosphere. I mean is it feasibly possible? Could we get this much aerosol up there without the use of a volcano? Would it be effective? Would it be safe? Should we do it? And these are the sorts of questions I’m interested in.  

Sam: So there’s been no attempt to do this at all. So far it’s just been recorded from volcano activity. 

Francis: Yeah, absolutely, no attempt to try and do this. I mean there would be a massive outcry if such a thing was attempted. And nor is the technology ready yet to be able to do it and one of the troubles with the earth’s system is kind of it’s one of the essential problems with the environment is that there’s only one earth and so we don’t have a spare earth to practice on, but the trouble is to see if it works you would need a big enough experiment to get a signal above the natural variation in the weather as opposed to climate and so we have to do lots of modelling tests, lots of laboratory tests and maybe in the future once we’re certain that these things work, we might think more about doing a limited field test but I mean that really is in the distance at the moment. 

Sam: So the Intergovernmental Panel on Climate Change have just released an AR5 report - and I don’t know much about this report but why is it significant?

Francis: So this report is the state or the nation address on climate change. There’s hundreds upon hundreds of international scientists reach a consensus on what the state of the science is for climate change at the moment and the state of the science is pretty much as people would have expected, that it is getting warmer, ice caps are melting, the ocean is warming, etc. These sorts of things have been in the news for a couple of years now but maybe one of the more controversial aspects of this report is that it did actually mention geo-engineering for the first time, so it had in its summary - it was only a paragraph in about a twenty page document - but it did mention geo-engineering which I think shows that geo-engineering is now being taken very seriously by governments and scientists alike and certainly there’s no consensus on whether it’s a good thing or a bad thing and there’s certainly a lot of disagreement and people get very excited about this on either side of the argument. But I think it’s occurrence in this report that shows we’re going to be hearing a lot more about geo-engineering over the next few years. 

Sam: So what does that mean for your research? I assume that’s a positive thing isn’t it?

Francis: Yes, I guess people are interested in geo-engineering and so my work, which in particular is on the environmental impacts of geo-engineering, not so much on geo-engineering itself but that will shed more light on my research and potentially more funding will come my way with any luck. So I should clarify from what I’m interested in in my research is the environmental impacts of geo-engineering and in particular stratospheric conjection of aerosols. So, we know that these aerosols will cool the climate, that has been shown nicely through volcanoes and modelling work. I think that’s fairly undoubtable now, but what I’m interested in is what’s the side effects of this process? So will there be other processes which will be changed by injecting these aerosols up there? And remember, we’re not talking about small amounts, we’re talking about a lot of stuff and so it’s already known that ozone destruction can occur upon aerosols and so that’s something that we might expect to happen more if we’re increasing the stratospheric burden of aerosols. So usually the stratosphere’s a fairly pristine place. If there’s no volcanic activity there's not many particles up there. After volcanic eruptions you get a big burst of aerosols but for this geo-engineering scheme, what it means is you’ll constantly have a lot of aerosols up there and in that case, does this mean we’re going to constantly have more ozone destruction? And so the mechanisms responsible for this ozone destruction is something I’m looking into. Something else I’m interested in is - so volcanoes release sulphuric acid, in effect, that’s what comes out of them, they release sulphur dioxide and this becomes oxides and creates particles of sulphuric acid. And so sulphuric acid is the natural chemical but it’s not the nicest chemical by any means, so one open question is, is there something better we could put up there? Is, for example, is there something like a mineral that something like deserts are made out of, could you put silica up there, could you put alumina up there, could you put titania up there? And potentially the good things about these particles is that they actually, pound for pound, reflect more light. So you might be able to get away with putting less up there. Plus you might have less reactivity up there and these are the kind of questions I’m looking at. So I’m looking at the atmospheric chemistry of not only sulphuric acid aerosol but also possible other minerals which could be used instead of the sulphuric acid. 

Sam: So it's a sort of discovery of different things you could send up.

Francis: Yeah, absolutely. 

Sam: So you’ve mentioned ozone depletion. Are there any other negatives to this?

Francis: Yeah and some of them known and some of them not known at the moment. So remember we’re trying to adapt a very complex system. So the earth, you know, there’s multiple feedbacks and it’s incredibly complicated and what we’re doing is a very brute force experiment, we’re putting a lot of things up in the air and so there undoubtedly will be unforeseen circumstances and so one of my jobs is to really try and work out all the possible unforeseen stuff that we can. But undoubtedly some things will slip through and we’ve got to be very careful about the unknown unknowns. Things that we do know which will happen is if we put something up there it will come down eventually, so there will be health effects probably. So, you know, there possibly might be eco-toxicology stuff. So if you push stuff up there it will fall on the ground, it will leech into the rivers etc, so we do have to be wary of creating problems like that. But potentially, or probably undoubtedly, the biggest problem with this is we’re not removing the CO² in the first place. So what we’re doing is, you know, the one analogy is the sticking plaster or maybe more precisely we’re trying to buy a bit of time whilst the world decarbonises its economy, but we’re not removing CO² so things like ocean acidification are still going to be going on. Yes, we might be reducing the temperature by reducing the sunlight but the CO² is still there and so we have to think about not only what’s the implications of having this additional sulphate layer or aerosol layer in the stratosphere but we also have to think of what the implications are of continuing CO² levels in the atmosphere as a whole. 

Sam: So it seems like we’re going to be hearing a lot more about geo-engineering as the time goes on, but that’s all for now so Dr Francis Pope, thank you very much.

Francis: Thank you. 

Outro VO : This podcast and others in the series are available on the Ideas Lab website: There's also information on the free support Ideas Lab has to offer to TV and radio producers, new media producers and journalists. The interviewer and producer for the Ideas Lab Predictor Podcast was Sam Walter.