Bill McGuire: Greenland's ice sheet might freeze UK

| 5th November 2019
Bill McGuire interview
When we melt ice sheets or raise sea-levels the change in pressure and weight on the Earth’s crust can trigger violent responses that very few will see coming.

So, there is hope that things… alright… they are going to be catastrophic but they might not be cataclysmic. Is that hope, I don’t know?

Professor Bill McGuire has a long history of researching and publishing peer-reviewed scientific papers on how the solid Earth responds to changes and how those responses affect civilisation.

His findings are often as awe-inspiring as they are frightening but as we move into the real-time scenario of extreme climate change impacts, his words now resonate more than ever before.

Nick Breeze (NB): Can you tell me a bit about your new book  - Knock Three Times - 28 Modern Folk Tales For A World In Trouble - and why it is a departure from your previous work?

Bill McGuire (BM): I have a history of writing academic books and then I moved on to popular science but I have taken a new path now; I am writing speculative fiction. 

Today's book has one of my stories in it. It is actually an edited volume that myself and a colleague, Andrew Simms of the New Weather Institute and Green New Deal, but it is a collection of 28 modern folk tales.

These stories are written by artists, and writers and scientists and business people, medics and they are trying to provide some hope… a hopeful message for people in a world that seems to be going to hell in a handcart.

NB: That’s a good choice of words. I think Professor Kevin Anderson used that at the COP a couple of years back when he was asked to give his appraisal of the situation.

BM: Well, I feel exactly the same way.

NB: You say hope in a troubled world but I have your last book here, ‘Waking The Giant’ and, I must say, it doesn’t make me feel terribly hopeful!

BM: Well, we always need hope because otherwise, we might as well give up now. If you take climate breakdown and global heating there is no doubt the situation is critical.

I don’t think you’ll find a single climate scientist, that if you talk to them in private, who will say that we are going to keep the global average temperature rise below even 2ºC.

So climate change is going to be catastrophic and all-pervasive. The less we do then the worse it is going to be still. So we have to act, we have to take serious action, otherwise, it is going to get worse and worse, even beyond catastrophic, if that is possible. 

But we need some hope to be able to do that, otherwise, everyone just gives up and we do nothing.

NB: We have a lot of context because we have 25 years of climate negotiations that have actually yielded nothing. People have become quite concerned now and that has happened quite quickly I think. But still, there is no real plan to move forward that is being adopted?

BM: I have certainly thought for some time that we will not see serious action on global heating until the effects start to become more and more apparent and I think in the last few years they are starting to become very apparent.

If you live in California at the moment, or Australia, or you experience the stronger hurricanes that we are seeing now, which we predicted, people are beginning to be aware and measures are starting to be taken.

I am not a natural optimist but I have some hope that within ten years we will see emissions plateau out and start to come down. That is too late to avoid catastrophic climate change but it is better than seeing them ramping up year on year on year, which they have been doing ever since the industrial revolution.

So, there is hope that things… alright… they are going to be catastrophic but they might not be cataclysmic. Is that hope, I don’t know?

NB: It is a kind of hope… I might switch from tea to gin! One of the things that really interested me in Waking The Giant was the historical precedent for freshwater tipping into the north Atlantic from melting ice sheets and which is analogous today with the run-off from Greenland and the so-called cold-blob in the north Atlantic.

BM: If you look at the temperature map of the whole planet, it is warming up. It is all reds and yellows, except this big blue blob in the North Atlantic just below Greenland. This is run-off freshwater from the melting ice sheet that is pouring into the north Atlantic It seems already to be having an impact on the gulf stream and associated currents which keep eastern North America, Europe and the UK warm. 

In the past, this kind of freshening of the North Atlantic has led to a shut down of those currents and it was thought that it took decades to happen, then it looked like it took years, then months, and, today we estimate it may actually have happened over a matter of weeks.

So we can see that the gulf stream and associated currents are already slowing dramatically. They are the slowest they have been for 50-100 years or so. It is supposedly unlikely that this mechanism will shut off but that is just guesswork. It could shut off and if it does it could happen almost overnight.

That would bring winter temperatures down in Europe and the UK to minus twenty-five and summer temperatures won’t get above about ten degrees centigrade.

NB: How far would that extend down to, in terms of Europe?

BM: The models I have seen show it is relatively restricted. It affects eastern North America and mainly the North-Eastern part. Then in Europe, it is the UK and Norway who are particularly badly hit and then on to western Europe.

The rest of the planet just goes on warming. Eventually, that cold would be overcome, if nothing was happening in terms of emissions reduction, even without the currents bringing up warmth from the tropics it would still warm up.

NB: So temperatures would override that eventually?

BM: Yes, eventually that would happen but in the meantime, we would be suffering in the opposite way. Cold rather than heat.

NB: The main focus in Waking The Giant is about saying that climate change has seismic and volcanic impacts. The world we live in today has been defined by these previous impacts from the last great changes. We are going through a great change now… can you take over from here

BM: Yes. People have a tendency to think that climate change is about the atmosphere, and maybe the oceans as well, but it is all-pervasive. It involves the solid Earth as well. Some people might think this surprising; how can climate change cause changes in the solid Earth? 

Particularly where you have thick ice sheets. If that ice, one or two kilometres thick, melts then the Earth’s crust starts to bounce back up again because the weight of the ice is [currently] keeping the crust way down.

If you have faults underneath that ice sheet that have not been able to move for hundreds of thousands of years because of the weight of the ice and, as it melts and is removed, those faults will rupture and generate earthquakes.

We saw at the end of the last ice age when the Scandinavian ice sheet melted, massive magnitude eight earthquakes, which you expect to get around the Pacific rim. You don’t expect to get them in Lapland!

We could see the same thing happening when Greenland melts. I have colleagues who work on the Greenland area and they say we could see a seismic response from Greenland within decades.  This is due to the whole north Atlantic region now coming up as a result of melting the Greenland ice sheet.

If you removed all the ice off of Greenland at the moment, the whole centre of it is below sea-level and that's coming up already. It will release the weight load [currently] on any faults underneath and if those start rupturing, not many people live in Greenland, but if those earthquakes trigger submarine landslides, there is lots of sediment around Greenland, they will generate tsunamis across the north Atlantic. We saw this eight thousand years ago when Scandinavia came up.

There are all these different knock-on mechanisms which can go, from ice-melting to tsunamis.

NB: This all seems very intangible to most people. I noticed walking through the vineyards in Champagne, which is over 300 kilometres inland, that there are fossilised seashells in the soil and that we are actually walking on an ancient seabed. But it feels too distant to comprehend.

BM: Well there is a problem with climate change in that sense. If people are not sure about what is going on with climate change the answer tends to be something like ‘oh well, our climate has always changed’. Well yes, it has but not like this - not as fast as this and not because of human-induced carbon dioxide emissions. 

I think people are getting a better idea of global heating and climate breakdown because of the impact on extreme events and extreme weather. People are starting to see things that they weren’t seeing before. 

I mean, the wildfires in California and Australia… this isn’t normal and people there will tell you this. Whole towns being obliterated.

NB: It is the interconnectedness isn’t it? If you are talking about agriculture, you have wine in California and you could live without wine but it is peoples livelihoods, it is an industry and all these things have knock-on effects starting from employment and jobs. If people can’t work they have to move and when they move they are not welcome where they move to, and so on and so forth, all the way to human conflict, which is itself a feedback.

BM: Even in the UK, people can see now that there is flooding every winter, all the time. Every week we have flooding and these are not one in a hundred-year floods, these are one in one-year floods.

One of the things we predicted is that there will not be more hurricanes but that they will become more and more powerful. If you take the one that hit the Bahamas, there has not been a sustained battering of a place for so long by one storm in modern history.

NB: We think of Europe and we think of it as such a quaint and benign place and yet in Waking The Giant you mention that Basel was once (1356 AD) at the centre of a huge earthquake and was destroyed. If we go further south to somewhere like Sicily where you have Etna, you have Vesuvius in Naples, or Stromboli where I visited a few weeks ago, are these at all a threat to us as the climate changes?

BM: Well I mentioned that the solid Earth can be affected when you take a great chunk of ice off the crust. All that water when you melt ice goes into the oceans. So at the end of the last ice age, all of the 52million cubic kilometres of water was taken off the ice sheets and dumped into the oceans.

That raised sea-levels by 130metres and this bent the margins of the ocean basins by bunging all that water in there. We published a paper in Nature in the late ’90s showing that there is a correlation between how quickly sea-level goes up and volcanic activity around the Mediterranean. 

So a big change in sea-level bends the margins around the coastlines and helps to squeeze magma out. A rise of two or three metres by the end of the century, which we could easily have, might set off volcanic eruptions in a shorter period of time than we would otherwise see.

NB: But isn’t this the point, that if you raise sea-level by two metres, you are going to cause so much social chaos that, if at the same time you have all these other impacts going on, it will put you on the back foot reacting to additional problems, like the collapse of agriculture for example?

BM: Yes, in its own right more earthquakes or volcanic eruptions might not be catastrophic but it is just one more thing on top of everything else.

This Author

Nick Breeze is a climate change writer and interviewer and also writes a great deal about wine. He is an organiser of the Cambridge Climate Lecture Series and Secret Sommelier

Bill McGuire is the author of Waking The Giant - How a changing climate triggers earthquakes, tsunamis and volcanoes’. His most recent work is within a collection of short stories called Knock Three Times - 28 Modern Folk Tales For A World In Trouble.

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