Source: BBC Radio 4: Today
URL: N/A
Date: 24/11/2016
Event: Sea ice now in Antarctica not "hugely different" to ice in days of Scott
Credit: BBC Radio 4
People:
Justin Webb: We're used to the idea that sea ice in the Arctic has been reduced by global warming, but a study conducted by scientists at Reading University has concluded that the ice around the Antarctic has barely changed in a century. The study's fascinating in part because it used ships' logs - Scott and Shackleton, and the like - to work out what the picture was in the past. Sammie Buzzard is a climate researcher at the University of Reading, and is here in the studio - morning to you.
Sammie Buzzard: Morning.
Justin Webb: That's an extraordinary study - how long did it take, and with what degree of painstaking effort?
Sammie Buzzard: Well, the data for this study actually comes from the ships' logs, from explorers such as Shackleton and Scott - some come from the 1900's and the 1910's.
Justin Webb: So you went through all those logs and you looked at - what, their descriptions of the ice around them?
Sammie Buzzard: Yes, so people on the ships would record everything, from weather conditions, sea states and whether or not there was sea ice, and so all of those logs had to be digitised and then the information about the sea ice was then put into into the study.
Justin Webb: And of course, crucially they were recording, as well, their position, their precise position -
Sammie Buzzard: Yes, exactly -
Justin Webb: So you could then go back -
Sammie Buzzard: - so we knew where the sea ice was, and when.
Justin Webb: And you found what?
Sammie Buzzard: Well, the study concluded that actually the ice today isn't hugely different from the ice back then, and actually sea ice in the Antarctic might be less sensitive to climate change than we maybe thought it was.
Justin Webb: Why would that be?
Sammie Buzzard: Well, it's hard to tell at this time, given that it's quite a new result... Um.
Justin Webb: It's really surprising, is it? I mean, you weren't expecting to find this?
Sammie Buzzard: Well, scientists have been struggling recently to try and explain why the ice has been increasing, because we would expect, in a warming climate, possibly the ice would be decreasing, such as we've seen so quite dramatically in the Arctic. But now we suspect that this might be part more due to natural variability of the ice.
Justin Webb: So what then are your theories about why it is that you'd have an effect seen at one end of the globe, as it were, and not at the other? And what are the potential theories?
Sammie Buzzard: Well, the Antarctic is very different to the Arctic - it's a big landmass, as opposed to an ocean - so we always expect it to change more slowly under climate. But the focus for that end of the Earth, we're more worried about the ice sheet itself, rather than the sea ice surrounding it, because that's the part where, if when that's melting and water gets into the ocean, that contributes to sea level rise.
Justin Webb: Because I just wonder whether some sceptics about climate change, or at least about man-made climate change, might leap on this and say "Hang on a second - here we are, we've got all this extra carbon in the atmosphere, it is possibly having an effect in the Arctic but it obviously isn't having an effect in the Antarctic, which just tells us that everything is more complicated and less easy to be clear about than it was before". Have they got anything like a point, if they say that?
Sammie Buzzard: Well, there are very clearly changes happening in the Arctic to the ice on the land, but the problem with working out things about the sea ice in the Antarctic is that there is so little data - anything pre-satellite, so we really know very little about what happened down there. That's why -
Justin Webb: But you've come up with it, now, you've come up with it.
Sammie Buzzard: Yeah, that's why studies like this are so important, to try and fill in those gaps, so we can start to explain what's happening.
Justin Webb: But what you've started to explain, though, is a pretty extraordinary story, as you were setting out at the beginning, that actually there hasn't been a change. When you say there hasn't been a change, there have been changes, is it right in saying, but those have been troughs, and, and dips, during the course of the century - in other words, are you saying things have remained exactly the same, all that time, or - or what?
Sammie Buzzard: No, they've not remained exactly the same, and we have seen a decline in sea ice, so from the dates of these studies to the present day there has been a 14%, roughly, decrease in sea ice. It's just not on the scale that we're seeing in the Arctic, where we're losing ice at a rate of about 13% per decade.
Justin Webb: Yeah... It's fascinating - what do you do with this information now?
Sammie Buzzard: Well, this information will allow scientists to further improve their climate models, so now we know more about the sea ice for a longer period, it gives us more information to put into those models and validate them and hopefully improve them, and learn a bit more about what's going to happen in the future.
Justin Webb: And presumably it will lead to an increase in the amount of effort given to looking at the Antarctic and looking at what's going on there.
Sammie Buzzard: Yes, hopefully so.
Justin Webb: Because these, these studies that you've done, and particularly the effort of working out exactly where ships were and what they were seeing at the time, as you were saying, hasn't been done before, and presumably now will be very widely shared.
Sammie Buzzard: Well, I hope so. Hopefully there's still a lot of data out there, for example from whaling ships, some of which has been looked at but some of it hasn't. So there's a lot more information to be digitised -
Justin Webb: I see, so there's more to come.
Sammie Buzzard: Yes, hopefully so.
Justin Webb: Fascinating - Sammie Buzzard from the University of Reading, thanks.