‘It's going to be a very, very heated debate’: geoengineering researcher Dr Robert Bellamy

Climate change is inevitable, and is already happening – but could it be controlled?

READ FULL STORY: Engineering the climate

From spraying reflective particles into the upper atmosphere to installing giant mirrors in space, exponents of geoengineering technologies hope they could limit the increase in global temperatures by reflecting sunlight back out into space.  

Such ambitious and unprecedented systems, if they are ever tested or deployed, will need strict regulation. Dr Robert Bellamy, senior lecturer in climate and society at the University of Manchester, is looking at how such research could be governed as part of the EU and UK-funded Co-Create project.

We spoke to him about the growing interest in geoengineering, the risks and opportunities – and what he thinks the future could hold.

Why do you think there is growing interest in deploying geoengineering tests?

We had some research programmes in the early 2010s. I was part of a few of those, and I think it’s fair to say that after that round of research funding, people started becoming quite sceptical about whether or not we'd be able to do geoengineering for various reasons, so it fell off the radar a bit.

Now it's coming back again, and my sense is that it's for the same reasons. People are again getting frustrated over the lack of emissions reductions and the threat of climate tipping points. It's different this time because there are some experiments taking place.

Without new geoengineering technologies and systems, are we on track to meet the international climate goals?

At a global level – no, I suppose is the answer. Based on current climate policies, I think we're headed for 2.7ºC, is what I saw last. So we're definitely headed for exceeding the 2ºC target, and the ambitions or aspirations to reach 1.5ºC are  vanishingly improbable.

But on the plus side, the 2.7ºC is actually a vast improvement on where we were a few years prior, when we were more seriously talking about getting to three, four or five degrees.

So there has been progress developing climate policies, but we're still not on track to meet those goals.

Do climate tipping points mean we need to move quickly?

That's one of the big motivations for geoengineering, potentially. When you think about the climate emergency it implies something that's going to be quite fast and quite large scale and drastic, and tipping points best fulfil that description.

When people talk about geoengineering, nine times out of 10 they're talking about stratospheric aerosol injection specifically. But there are a whole bunch of other techniques under that bracket, like marine cloud brightening, or space mirrors, or urban albedo modification, or crop albedo modification, or cirrus cloud thinning. There's a whole list, some of which are faster than others.

If you wanted to reduce the Earth's temperature very, very quickly, then something like stratospheric aerosol injection is probably one of the few things you could do, like potentially quite short notice, to reduce the Earth's global temperature.

Would solving the engineering challenges involved be feasible?

The general consensus is yes, it should be quite easy to do, although again it depends on how you're delivering it. One of the most popular proposals is that you would send up a fleet of aeroplanes, which we obviously already have. You might need to modify them a little bit to accept the payload, but that's fairly standard.

Then you've got things that are a bit less standard, like balloons. So for example, the Spice (Stratospheric Particle Injection for Climate Engineering) project was going to test a delivery mechanism for this balloon system where you'd have a high altitude balloon that would go up to the stratosphere, 20km. And it'd have a tethered pipe to the ground, you'd pump up your sulphur through that, then the balloon would release it at the top.

As far as I understand, that is a bit more complicated because we haven't really done that, and there's big questions around how the pipe would respond to wind conditions and other things. And that's what the Spice project was going to be doing, testing whether that would work. So there is still work to be done there.

Then at the other end of the scale, you’ve got things like space elevators – which are obviously a massive engineering challenge that will probably never happen.

Installing large mirrors in space also sounds like it would involve solving major challenges…

There's different options for that. There's placing mirrors in Earth orbit, like a fleet of small mirrors, or a big mirror. You could have dust clouds. Or you could have rings, like Saturn’s, placed around the Earth. There's a whole bunch of quite interesting ideas.

But historically, certainly back in the 2000s and early 2010s when we first started talking about this stuff, people were very sceptical about it. And I think there's good reason to still be sceptical about it – but there have also been some very interesting developments in the ‘new space race’ recently, which I think maybe offers some cause for improved optimism.

A lot of people have been talking about reusable rockets, which will help bring down costs, and then there's the possibility of in situ fabrication. You could manufacture the materials either in orbit, or on the Moon or on an asteroid or something, instead of having to bring the materials up and down from Earth.

So there are some new ideas that are starting to come onto the scene that might make it a bit more plausible.

What are some of the main potential risks involved in geoengineering in general?

Termination shock is the big concern, that if we ever wanted to do this and we weren't reducing our emissions in the background – and then for whatever reason the geoengineering stops – then we'd get a big spike in temperature.

Changes to global circulation patterns have been seen in climate modelling work that  tried to look at what would happen if we use these technologies, and all the knock-on effects that might have on agriculture, for example.

Or the geopolitical risks as well, you start getting into those – what happens if one country starts to do this, and other countries aren't onboard with it, or if one country suffers a drought one year, next door to a country that has been doing this? It introduces issues of compensation and potential conflicts. It's a bit of a minefield, in terms of risks.

Is the Co-Create project considering those risks, and how the systems could be regulated?

We'll be thinking about all of those risks and challenges that the different technologies pose, and what that means for governance. How do we control all those things? In our project, we're particularly concerned with research and experimentation, as opposed to eventual deployment – although there is an argument that it's not so easy to distinguish between research and deployment in certain cases.

Would geoengineering deployment need backing from a large intergovernmental agency, such as the UN, to succeed?

A lot of people would agree that you need some multilateral arrangement. You could get a scenario where individual countries just go and do it. But I think most people would say it's desirable to seek a multilateral agreement on how these things should be used.

Is it possible that a country acting on its own could use geoengineering to regulate its own average temperature, and not elsewhere?

It depends on the technique, but I'd say it's probably very difficult, if not impossible, to keep it confined to a single country. With these tests that have been going on around the Great Barrier Reef, that's being done with the intention of reducing the coral bleaching and temperatures in that localised region.

But when you're doing things in the atmosphere, that inherently has transboundary risks, passing from one airspace into another.

Is there a risk of more pollution from stratospheric aerosol injection?

There is a pollution element to it. One of the risks of doing stratospheric aerosol injection is possible depletion of ozone, which is another global environmental problem we have, of course.

We’re also putting out a lot of particulate matter through fossil fuel combustion. And actually one thing we've noticed recently is that with the decreasing use of coal, the particulate matter from coal combustion actually cools the planet a little bit – it's ironic, because you're taking away the pollution aspect and it ends up warming the planet a little bit, even though you're also getting rid of the carbon dioxide that's being released.

How do you feel about the future – do you think we will need these new technologies and systems?

Wow. I think we should be researching them and I think we need to develop a governance system for that research, and certainly to anticipate any potential deployment. Do we need them? I don't think so yet.

But it will come down to a matter of opinion. At the end of the day, at what point does climate change become an issue that requires an intervention of that scale?

Could Western governments start seriously considering it if their citizens face more extreme weather and food shortages?

Yeah, that would be one answer, for sure. You could also argue that we already have those kinds of climatic problems, and indeed we had those problems before anthropogenic climate change. On that basis you could justify doing geoengineering already.

It's going to be a very, very heated debate – it already is a very heated debate.

And one that the engineering community needs to be involved in

Absolutely. They are the heart of this in many ways – developing the delivery mechanisms, the technical equipment that would be used to deliver these things.

But I suppose that the key thing to remember here is that these technologies, if we ever develop them, won't just be bits of kit. They’ll be what we call socio-technical systems. They won't work without procedures, without policies, without governance. It's key for us to have an interdisciplinary endeavour. Engineers need to be having conversations with social scientists, and vice versa, across the disciplinary spectrum.