An Expert View on Carbon Capture And Storage

My name's Myles Allen and I'm a professor of Geosystem Science at the University of Oxford and I'm going to explain to you why you shouldn't panic about climate change. That doesn't mean that global warming has stopped - far from it. In fact, the climate is changing pretty much exactly as we predicted it would change, back in the 1990s. Even if the climate turns out to respond right at the low end of the current range of uncertainty, we're still looking at dangerous climate change, well over 2 degrees of warming by the end of this century, if current emission trends continue. So no matter what happens, if we're going to avoid dangerous climate change, we need to reduce greenhouse gas emissions. So the big question is: How? How do we solve the problem... ...and which are the most important greenhouse gases? Carbon dioxide is not the most powerful greenhouse gas molecule for molecule, but it matters because we emit an enormous amount of it. In fact, since the beginning of the Industrial Revolution, about 250 years ago, we've released about 500 billion tonnes of carbon from fossil sources and from deforestation, into the atmosphere, and about half of that, so about 250 billion tons of carbon, is still in the atmosphere, still continuing to affect the climate. This is why carbon dioxide is so important, because it hangs around for such a long time. Let's talk about the implications of this longevity of fossil carbon with a little demonstration here. OK, so here's a very simple model of the global carbon cycle. Each of these cans represents half a trillion tons of fossil carbon. So back before the Industrial Revolution we had 4 trillion tons of fossil carbon underground in the form of coal, oil and natural gas. Over the past 250 years we've extracted, and dumped into the atmosphere, about half a trillion tons of fossil carbon and as soon as we start adding more carbon by burning fossil fuels, we pour this out of our chimneys, into the atmosphere, and it immediately starts exchanging with other parts of the carbon cycle, the oceans and the biosphere - that's animals and plants. But crucially, if we stop pouring into the atmosphere, then levels don't go down again, they stay more or less where they are. We've just reached the end of our first half trillion tons of fossil carbon. Now, we took 250 years to release the first half trillion tons of fossil carbon into the atmosphere. If current emission trends continue, we'll release the second half trillion tons in under 40 years. So, by the 2040s, we will be releasing the trillionth ton of carbon. Now the reason this matters is there's a very simple relationship between the total amount of carbon we dump into the atmosphere and the eventual warming we experience. Each of these cans is worth about a degree of global warming. As we pour the next half trillion tons, we are pushing up the temperature we will eventually have to face. And that temperature will continue to rise as long as we're continuing to pour carbon dioxide into the atmosphere. The only way of stopping climate change is by stopping the flow of fossil carbon into the atmosphere. So how are we going to avoid making this gadget overflow? How are we going to avoid releasing... ...more than a trillion tons of fossil carbon... ...and pushing global temperatures over 2 degrees? What really matters, for the future of the planet, is what's going to happen to the second, third and fourth trillion tons of fossil carbon underground. Thinking about the problem in this way, and recognising the importance of the accumulation of carbon in the atmosphere makes it very clear which are the pivotal technologies for addressing the problem of climate change. It is completely inconceivable that we will introduce a carbon tax that's high enough, or an emission control regime that's so strong that this fossil carbon will be left underground forever. This stuff is too useful, it's too valuable, it's going to get used, we have to recognise that reality. So the crucial question is: Are we going to work out, in time, how to use it without dumping... ...the fossil carbon into the atmosphere? The technology I'm talking about is called carbon capture and storage. This is the technology which allows us to generate energy from fossil carbon, capture the carbon dioxide so generated, and pump it back down underground so it doesn't affect the climate. Now this has been used on a small scale, on a relatively small scale, for decades. But crucially, we have no idea what's going to happen when we start using carbon capture at the scale of billions of tons of fossil carbon. We're only going to know if we can do that, we're only going to reassure the public that we can do so safely if we start work now. It's an extraordinary challenge, but the fossil fuel industry has stepped up to some pretty extraordinary challenges in the past. We can't rely on emission trading systems and carbon taxes to drive the development of carbon capture and storage. Until carbon capture is made compulsory, made a condition of extracting fossil carbon out of the ground, we won't be building the technologies we need to avoid dangerous climate change.