Melting Antarctic and wildlife decline

"If Antarctica did melt, what would that do to sea levels around the world?" Chris Smith talks climate science with Ella Gilbert from the British Antarctic Survey, with further reflections from space scientist Katie Mack and space journalist Richard Hollingham...

Chris - It's also been a big week for climate change this week. Ella Gilbert's a climate scientist, she's at the British Antarctic Survey. Ella, thanks for coming on the program. Lots of headlines this week! This is off the back of the report from the Zoological Society of London's biannual Living Planet Report with the World Wildlife Federation: they say, on average, global populations of mammals, birds, fish, amphibians, and reptiles have plunged by 68% between 1970 and 2016. Two years ago that figure was only 60%. We've got the stories about record levels of melting ice from Antarctica; new models about how warm water is being forced into Antarctica to melt the ice there at an alarming rate. If Antarctica did melt, what would that do to sea level rise around the world?

Ella - If the entirety of the Antarctic ice sheet was to melt, it would raise global sea levels by an astonishing 58 meters. Now that's not likely to happen anytime soon, but it's a really vast amount of water that would completely inundate, essentially make coastal areas around the world virtually uninhabitable.

Chris - Yes, I did read somewhere that many of the major cities, because they're all situated on rivers and rivers by definition tend to be in quite low places, most of the world's major cities that we all cherish would be at significant risk. What sort of timescale would that risk come over though? When are these cities likely to become vulnerable?

Ella - Most major cities tend to be at quite low level, which means that any degree of sea level rise is likely to have an impact. It doesn't necessarily require 58 meters of sea level rise to start seeing the effects of climate change and sea level rise. We're already seeing them. Within the next century, within the next few centuries, we're likely to start seeing quite intense effects of sea level rise. And of course that's exacerbated by intensifying extreme weather events, and storm surges, flooding, that kind of thing. And obviously there's the uncertainty associated with what future trajectory our climate takes, whether we start mitigating climate change sooner rather than later, and what we actually do to combat it.

Chris - There was a paper in Nature Climate Change just recently: they found that the rate at which the polar ice caps - including the Antarctic - are melting, actually are following our line of worst trajectory prediction. In other words, we said "worst case scenario, best case scenario, we expect to be somewhere between those two margins," and actually it looks like, the rates we're measuring, we're on the worst case scenario; which doesn't really bode well.

Ella - No. I read that paper the other day and yeah, it's quite clear and stark in its conclusions. It shows that the rate of observed sea level rise is on track to completely... I mean, it's virtually indistinguishable, the line between the worst case scenario and observed sea level rise, essentially. So that isn't good news. And that's largely because of surface melting in Greenland, which is mostly caused by temperature rise and the kind of heat waves and extreme weather we've seen there in recent decades; and then also by what we call dynamical change in Antarctica, which is basically bits breaking off and glaciers speeding up.

Chris - Richard, getting into space has played a huge role in our being able to make the sorts of measurements that the Ella is relying on when she's doing her research. People actually weighing Antarctica from space using satellites.

Richard - Absolutely. Earth observation, as it's called, which are these satellites that observe the earth, which essentially... they started off as spy satellites, but now are just crucial for our understanding of weather, of climate, of the makeup of the earth, of the amount of ice on the earth. And CryoSat for instance, the satellite from the European Space Agency, is measuring ice coverage continuously using radar across the globe. So we have a pretty good idea now of what's happening. And you just look at, as we were saying, these horrifying headlines: wildlife in catastrophic decline, the fires in California, what they're calling the Doomsday Glacier in Antarctica; and I guess I wonder there how you stop from being overwhelmed, and how we can... can't be positive about this, but there must be positive action we can be taking based on the science?

Ella - Yeah, that's a question I often get actually. I find that I've become relatively desensitised to these sorts of terrifying headlines, having engaged with them for very many years. I think you have to focus on the positives, like you were saying, thinking about the good things that have happened to you in the day; possibly thinking about the small wins that we do see, the things that are less bad than we expected, or the solutions that people are coming up with. I do take lots of encouragement from the really cool net zero technologies that are being developed, and the projects that you see that are using innovative solutions to actually combat climate change, and the sorts of huge changes, and the rise of popular awareness and passion for climate mitigation: for instance, the citizens' assembly on climate change, or the proliferation of protest against climate change. Everyone is talking about it and that can only be a good thing.

Richard - It's interesting you mention that citizens' assembly because that was ordinary people - if you want to put that in inverted commas - but people from across the country coming up with, "well, the policies that the politicians put into effect, what policies should those be?" And I think politicians have been quite surprised that they're really quite emphatic that we need to do something about it, and it needs to be led by governments; not just the government, but governments around the world.

Ella - Yeah, it's really amazing to see that people are actually taking democracy on climate policy into their hands and that it needs tackling on a vast scale, it needs to be national level and it needs to be international level; which is something that I suppose has been talked about for a long time, but to have the mandate from people who, like you say in quotes, are "ordinary", is really strengthening.

Chris - Katie, what's the mood like in the US? Because of course your country has been hit by a lot of the consequences of these things, with intensifying hurricanes, there's been quite a lot of storm activity, and then of course the wildfires that we've seen raging on the west side of America; has that shifted people's thinking?

Katie - I think there is a general shift where more people are understanding that these kinds of big events are connected to climate change, and more common because of climate change; and I think that that is getting into the popular consciousness. Unfortunately on the federal government level climate protections are just decreasing in the last few years, and there's backward action at the moment from the top, but I do think that there is more of an awareness. And one of the things that I was wondering about, Ella, if you wanted to comment on this: there's been quite a lot of interesting innovation in remote connection, remote conferences - I've attended a few remote conferences and some of them have been really very good - and a lot more remote work and so on. Do you think that the developments that have been happening because of the pandemic, and more of this remote work, more of these remote meetings; do you think that will substantially cut down on people flying all over the world within academia, and other industries, to meet with each other? Or do you think this is just a temporary blip and it's everybody's going to hop in airplanes again as soon as they can?

Ella - That's a super interesting question. I was actually speaking on a panel where this came up before, and...

Chris - You didn't fly to that panel did you Ella? Just asking…

Ella - It was on Zoom! Yeah, lots of organisations I think are trying to decarbonise; and that inevitably includes cutting down on flying, and carbon expenses, and getting to conferences, which are of course a vital part of academia and knowledge sharing; but can, as we've seen, be done remotely in a really successful and effective way. So I think it's been a kick up the backside for a lot of organisations. The proof of concept is there, we can see that these vast conferences, with normally 20,000 attendees or something in that vicinity, can be done online, and that people still engage with them. Of course there's going to be tweaks to be done, but I think the fact that we've successfully managed to do it so quickly just demonstrates how easy it will be, and I do think that it's going to be something that we see more of in the future.