25 Mar 2014
Prof. Myles Allen on climate change, flooding, and carbon capture as a ‘silver bullet’
Today we talk with Prof. Myles Allen, head of the Climate Dynamics group at the University of Oxford’s Atmospheric, Oceanic and Planetary Physics Department. He is a prominent and widely published climate scientist. He also wrote a recent article in the Mail on Sunday called Why I think we’re wasting billions on global warming, by top British climate scientist. It began “we have campaigned tirelessly against the folly of Britain’s eco-obsessed energy policy. Now comes a game-changing intervention… from an expert respected by the green fanatics themselves”. What’s going on?
We will come on to that interview later in this piece, but the first thing I wanted to discuss with him was the recent floods the UK has experienced. Allen was recently involved in publishing a paper which looked at the extent to which climate change could be responsible for the 2000 floods.
He told me:
“The 2000 floods were really the first major event that got people talking about the possible role of climate change in these events. But of course it’s always a difficult question to answer because floods have always happened. The UK has always had high rainfall variability and so in some seasons we get more rain than others and as a result we occasionally get floods.
So the question is whether what we’re seeing now is just the normal run of bad luck in British weather, or whether climate change might be playing a role in it. That was the sort of question we set out to answer in the study we published a couple of years ago.
The key point is you can’t say, as a lawyer might put it, that but for climate change this event would not have happened. Because these are all events that might have happened anyway in a hypothetical climate in which we hadn’t increased greenhouse gas levels.
But what we can say is to “what extent has climate change or human influence on the climate made this event more likely to occur, or probable”, and that was what we looked at in that study. We came to the conclusion that on average human influence on the climate through rising greenhouse gas levels had more or less doubled the risk of an event such as occurred in the autumn of 2000.
But there was a big range of uncertainty on that. It might have been more than double, it might have been a good deal less than double. But we were fairly confident that the risk had at least gone up and that was the conclusion we drew. As you can see, it’s a fairly complicated message! A lot of people like us to answer the question “was climate change to blame or not?” The bottom line is it doesn’t make sense, for a random event like a flood, to say climate change was entirely to blame or entirely not to blame. We have to look at how the probabilities may have been changed through our changing climate.
If, with the floods of 2000, climate change doubled the probability of those events happening, and we’re now 14 years further into the warming process, would one therefore be able to infer that the floods we’ve just had were made even more probable by climate change?
Just because one kind of flood has been made more likely by human influence on the climate, it doesn’t mean all kinds of floods have been made more likely. That said, the circumstances we’ve seen this winter are not dissimilar to what we saw in the autumn of 2000, so perhaps human influence has played a role, but we are actually running experiments at the moment to find out, and I don’t know what the outcome of those experiments will be. It’s reasonable to suspect that human influence might have played a role, but until we’ve got the numbers in we shouldn’t really say either way.
Do you still think that staying below 2° is possible and/or feasible?
You’re talking about 2°C, the internationally agreed goal of 2°C above pre-industrial temperature. To remind people that that means really not much more than 1° above today’s climate.
First of all, it would be a very good idea, very desirable for us to do that, primarily because as a climate modeller, I don’t really know what a climate 3 or 4 or 5 degrees warmer than pre-industrial would be like. That might not be the thing you would expect from a climate modeller, but as you will appreciate, the further we go from the kind of conditions which we can test our models on, the more concerned we are about trusting what they tell us. I would be very worried about relying on anybody’s projection of what a world 4° warmer than pre-industrial would be like in detail, and for that reason alone I think limiting warming to 2° would be a very good idea.
So I fully support the goal. You asked whether we think we’ll manage it. I think we could manage it. There’s no question we still could do it. The reality is it’s not too late. But that’s not to say we don’t have a problem or a very substantial challenge in meeting that 2° goal. Just to put it into simple terms for people, global temperatures are largely determined, in the long term, by the total amount of fossil carbon we’ve dumped into the atmosphere.
Back at the beginning of the Industrial Revolution, we had around 3-4 trillion tonnes, that’s 3-4 thousand billion tonnes of fossil carbon sitting underground waiting to be dug up and burned to power the Industrial Revolution. Over the past 250 years, we’ve dug up and burned about half a trillion tonnes. Over the next 35 years, at the current rate, the way things are going, we’ll burn the next half trillion tonnes and the next half trillion tonnes after that will take us over 2°.
That puts the challenge into perspective. We have to somehow work out what we’re going to do with all that fossil carbon underground that would be immensely profitable to dig up and burn if we’re not going to dump it all in the atmosphere very substantially greater than 2°C. That’s the challenge we have to face, we have to bear that in mind when talking about whether we’re going to meet the 2° goal. I think we could do it, but I’m not convinced that the current policy, that the majority of current policies are actually particularly helping towards that goal.
James Hansen has been arrested for trying to stop coal trucks in the US and Kevin Anderson has been quoted as saying that he feels that civil disobedience is one of the only routes to actually dealing with climate change. What’s your take on the balance, as a climate scientist, between stepping across into doing something about it or just documenting the process and gathering the science?
I’m pretty conservative on this one. I think it is our job to do the science as you described. I don’t think where we get our funding from or what our political views are really make much difference to the science we do, and we should always take very careful steps to make sure it doesn’t make much difference to the science we do. When I’m doing climate science I’m working in a community which is working together to understand the system as best we can and that’s very different. I don’t think my political views really come into it at that point.
Just going back to Kevin Anderson for a minute, he was published recently about arguing that his sense is that economic growth and adequate response to climate change are incompatible with each other. What’s your sense of that – is it possible that you can still have a growing economy that is capable of staying below 2°C?
I absolutely do, yes. I respect Kevin’s views on this, but I don’t think there’s any hard evidence that economic growth and climate mitigation are incompatible. I feel as a matter of policy it’s very unhelpful to suggest that there are alternatives, because all of the countries in the world feel that economic growth is their imperative and understandably so, because they have a lot of poor people, a lot of mouths to feed, and if people tell them that doing something about climate change is an alternative to economic growth then many of these countries would, entirely reasonably, say “well let’s concentrate on economic growth first then”. So no, I don’t think there’s any incompatibility between a growing economy and addressing the problem of climate change.
You wrote a recent piece in the Daily Mail, in which you argued that the only route forward to talking climate change was carbon capture and storage but it’s still an experimental technology. Is there a danger with putting all our eggs in one basket in terms of risks, do you think?
In a sense we’ve only got one basket to put the eggs in, if you think about the problem from a perspective of the overall carbon in the ground. We started off with three and a half trillion tonnes of fossil carbon under the ground. We’ve burnt half a trillion tonnes, we’ve got three trillion to go, more or less, and we’re cracking through the remainder. If we want to limit warming to 2°C, we have to limit overall carbon emissions in the atmosphere to less than a trillion tonnes, possibly one and a half trillion but not more than that. That still leaves a couple of trillion tonnes of fossil carbon in the ground, available to be converted into useful energy.
That just really leaves us with three options:
- We burn that carbon, dump the CO2 in the atmosphere and suffer the consequences in terms of climate change
- We introduce a global climate mitigation regime that’s so stringent, so draconian that no-one ever in the world is allowed to dig up that fossil carbon and burn it.
- We sequester the carbon before it enters the atmosphere
That second option is one which I would actually regard as pretty frightening in itself. I find it very hard to believe that we would set up some kind of global carbon governance regime that is that strict. If we can’t do that, then we just have to accept that some of that carbon which cannot be dumped in the atmosphere is going to be.
We’re talking about building an industry from scratch in effect today (carbon capture and storage), comparable to the fossil fuel industry itself, and we need to do that over the next two or three decades, which is why we need to be getting on with it. Without it, we will not solve the problem of climate change because we will continue to use these fossil energy sources.
We might use them slower if we are successful in improving our energy efficiency and so forth, but the key point is that it really doesn’t make any difference using carbon slower if you still burn it all in the end. In the end it’s the total amount of carbon you dump into the atmosphere that matters, not the rate you emit in any particular year.
You’ve been involved in publishing papers on climate change since 1999 and know as much about this as many people, I’m sure. How do you live with it in your daily life? How does knowing what you know about climate change impact on how you live and how you live with that information?
One thing’s for sure, the bulk of my carbon footprint is spent going to IPCC meetings, which is ironic but also highlights the difficulty of relying on personal behaviour to address the problem. Until the problem is addressed at the source, until we essentially engage the fossil fuel industry in solving its own waste disposal problem rather than asking individuals to tighten their belts and reduce their carbon budgets, we’re not really going to make a serious dent in it. While I think, obviously, there’s an excellent case for people diversifying their energy supplies and reducing their energy consumption, there’s an excellent economic case for doing that, an excellent energy security case and so forth. But we also need to be realistic. We need to recognise that we’re not going to solve the problem of climate change until we solve it at source, until the fossil fuel industry essentially is required to take responsibility for the waste products of the products themselves.
For the rest of us, what will characterise living with climate change over the next 20 years, do you think?
The consensus prediction is reasonably clear, that we should be expecting to see a higher frequency of warmer summers and wetter, warmer winters. But there’s obviously a lot of variability around that, and we’re still a long way from seeing, as I said at the beginning, weather events that simply wouldn’t have happened without climate change.
In the UK at least, because there’s a lot of weather variability in this part of the world, I think detecting the effects of climate change on the UK will take a while. In some respects it’s one of the hardest parts of the world to see the impacts of climate change coming through. I think it will be much more obvious, and already is, the impact of climate change on places with less year to year variability such as Africa and Australia for example”.
[Editor’s note] In the interest of balance, I’d like to close this piece with a link to Joe Romm’s fierce response to Allen’s Daily Mail article, and to Allen’s proposal that all other attempts to reduce carbon emissions through demand reduction, renewables and so on are a waste of time, with carbon capture and storage being the only solution. It is an essential companion piece to read alongside this article.