Source: BBC Radio 5 Live: Radio 5 Live Drive
URL: N/A
Date: 19/05/2014
Event: Andrew Shepherd on Antarctic ice loss study - "everybody should be concerned"
Credit: BBC Radio 5 Live
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Caroline Barker: Next, one of the most shared stories on the BBC website at the moment - Antarctica is now losing ice at a rate of 160 billion tonnes a year to the ocean. That's twice as much as when it was last surveyed, over five years ago. The new assessment comes from data from the European Space Agency, the loss enough to push up global sea levels by almost half a millimetre per year. Professor Andrew Shepherd's from the School of Earth and Environment at the University of Leeds, and led the research - thank you for joining us, Professor.
Andrew Shepherd: That's fine, thank you for calling.
Caroline Barker: So why's this figure doubled in such a short space of time, then?
Andrew Shepherd: Well, it's a couple of reasons. We've used a satellite that was especially designed to look at Antarctica, whereas in the past we used satellites that were really designed to look at the oceans, and this satellite can now see parts of the continent that we couldn't see before. And we now find that those areas are actually losing ice, and so that adds to what we knew about, but also we also see that the rate at which ice is being lost has increased as well.
Caroline Barker: So are we actually saying that things have dramatically sped up that much, or just that we've got better data?
Andrew Shepherd: It's a combination of the two things, but the person that's interested in sea-level rise, it doesn't really matter what the reason is - we now have a better handle on it and it's twice as big as we thought it was.
Caroline Barker: Is there anything we can do to stop this retreat?
Andrew Shepherd: I think if you read the papers that were out - the studies that were out last week - I think people tend to think now that we're in a phase where this retreat is going to carry on, irrespective of what happens in front of it, and that's in the oceans. What we really need to know, as climate scientists, and actually as members of the public, what we want to know is how quickly it will happen, not really whether or not it will happen.
Caroline Barker: Can we do that? Can we predict accurately what happens in the future?
Andrew Shepherd: Well, um, the best thing we can do is use climate models, and the climate models we use are only as good as the information that we give them, and so, in this particular example, we're looking at Antarctica, the information those models had a week ago, before our study was released, was wrong, and so we would expect the people that run those models to use the latest information, and revise their predictions. And, as I said, the latest information is that Antarctica's losing twice as much ice as we thought it was.
Caroline Barker: How worried are you?
Andrew Shepherd: As a scientist, I think I'm intrigued and I want to understand why ice has been lost faster than we thought it was, and what the implications are for the future. As a member of the public - because I'm that, as well - I am concerned and everybody should be concerned, because this is a signal that's happening and it's been increasing over the past 20 or so years now, and - most of my lifetime - and we should be concerned about what might happen in the next 20 years and the 20 years after that.
Peter Allen: Yeah, um, it's Peter Allen here, Andrew - sorry to interrupt. But, I mean, it is a vast reservoir of ice, Antarctica - how much, at present levels, how much will water levels, sea levels rise, as a result of the kind of melting that's going on at the moment?
Andrew Shepherd: This study that we released shows that today Antarctica is causing sea levels to rise by half a millimetre per year. If we contrast that with the last study, five years ago, Antarctica was causing sea levels to rise by a quarter of a millimetre per year. Well, these numbers don't seem a lot but most people can double numbers every five years, and if you did that - and that's not what we do, as climate scientists - but if you did that, that would lead to quite an alarming sea-level rise in the next century, so we have to do better than that. We use climate models to make a physical prediction, and it's less than that, but Antarctica, West Antarctica is part of it, could cause sea level to rise by over a metre.
Peter Allen: Right. Thank you, that's Professor Andrew Shepherd - there's a lot more in Antarctica as well, but if it does finally melt, it will probably be a bit late for us to worry about.