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29 Oct, 2021 06:27

No ice may be left by 2100 – glaciologist

Rising sea levels, cities covered with smog, hurricanes, and storms wreaking havoc – climate change is an issue of our own making that could soon be felt in every corner of the planet. Can we reverse it? Or is it too late? We asked Professor Martin Siegert, glaciologist and co-director of the Grantham Institute for Climate Change at Imperial College London.

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Sophie Shevardnadze: Martin Siegert, welcome to the show. It's really great to have you with us. So Martin, most of us agree that the climate is indeed changing, and it isn't a hoax and that things are going to get worse with time. So how much do we have left before apocalyptic scenarios? Like the ones we're seeing in ‘The Day After Tomorrow’ movie?

Martin Siegert: Well, so there are some nightmare stories that are out. I think we have to look at the evidence of climate change and recognise that the whole issue of climate change is scientifically extremely sound, so that we know climate change is happening, we know that we are responsible for it, for the emissions of greenhouse gases into the atmosphere. And we know that we can do something about it. The question that we have is, how much time do we have? It's a very good question. It’s going to be more than just a few minutes to answer that. So we might want to unpack that question a little bit to give it a full answer. We can certainly look into the past to understand how climate change has happened in the past. And that gives us a context for the changes that we're seeing now. And then we have to discuss what we can do about it. And there are many things that we can do. They're quite complicated, they're quite varied. But we need to take action right now.

SS: Just a guess or not a guess: how much do we have left if nothing is done until everything goes really bad?

MS: So we look at the amount of carbon dioxide in the atmosphere that we have today. And it's about 410 parts per million. Now that's quite high greenhouse gases. Carbon dioxide is a greenhouse gas, and we know that it's warming the planet. It's gone up to that level from the Industrial Revolution in about 1850 when the carbon dioxide concentration was 280 parts per million. So it's gone up over 100, within about 100 years. Then the global warming has been about one-degree centigrade in that time. So there is a one-to-one association with the level of carbon dioxide and the warming that we've seen since we started burning fossil fuels. Now, you have to go back a long way in the past the last time that the Earth had 400 parts per million of carbon dioxide. In fact, you have to go back about 5 million years, geologically, there was a time called the Pliocene. And in the Pliocene, the global temperature was about four degrees warmer than it is today. And the sea levels globally were about 20 to zero meters higher than they are today. So if carbon dioxide is the temperature control on the planet and it's reasonable to expect that it is, we've got a lot of changes coming our way in the coming decades and centuries. That then the question is, what do we do about it? And of course, what we need to do is to stop emitting fossil fuel carbon emissions – We need to do it quickly...

SS: Completely? Are we talking about reduction or complete – ?

MS: Well, so the first step is to reduce it, but ultimately, it is to take it away entirely. The Intergovernmental Panel on Climate Change has a plan to limit global warming to another half a degree centigrade. That's, that's what's called the 1.5 degree report. So we're already one degree warmer than we should be and there's some things that we're locked into that we can't change. But there is a plan to limit global warming to another half a degree centigrade. But what it means is that we have to deliver a net-zero global economy, in terms of carbon emissions by 2050, by the middle of this century, that's 30 years time. And that was really a lot of things were discussed in Paris at the famous Climate Summit, and are being returned to annually to think about progress that's being made. Essentially what we have to do is to cut emissions by about 40% by 2030 and then to zero by 2050.

SS: So if things don't go the way you are saying where every big country agrees to reduce carbon emission by 2050, you know, your colleague Thomas Crowther actually said that Moscow's weather is going to be like Detroit and London will resemble Barcelona while Madrid's climate will be more like Marrakesh’s. And if things do go like this, does that mean that cities like Tripoli, or Mecca or Phoenix will basically become inhabitable due to unbearable heat? I want you to say things like this out loud because I don't really think that people realise, all of them, how serious this issue is.

MS: For sure. So so each part of the planet is experiencing unusual conditions right now. In the United Kingdom, we've experienced a lot of flooding recently, we've had droughts in recent years, we've had a lot of storms in recent years. And each of them are highly unusual, they can be regarded as sort of one-in-100-year type events. And they're occurring more regularly, they're becoming more like one-in-10-year events. And an increase in extreme weather is something that is predicted with global warming. We've seen wildfires in Australia, in California, in the Arctic, in many places, we've got droughts in many places, extreme heat in some places, and catastrophic rainfall. These are things which we would expect under climate change scenarios and, unfortunately, it's starting to play out. And I think that's an important thing to recognise, because we talk about government action on climate change. And actually, governments can only do so much to cause the changes that are needed. It needs people to take responsibility for their own carbon emissions. And it needs businesses to recognise that the future, their future, in the next 30 years is going to be very different to their past. And actually, that's quite exciting from a business perspective because there's lots of opportunities for new ways of thinking and working in the coming decades, and business should be embracing this change.

SS: So I'm just thinking if we don't take responsibility will snow become some sort of like exotic thing, not just for people from Saudi Arabia, but even like, for northern parts of Russia, and United States and Canada?

MS: Yeah, it kind of sounds a bit flippant when we start to talk about weather. But actually, these things are quite serious. So when we're talking about snow, essentially what we've got with snow is a very large accumulation of water stores frozen on the surface of the planet that then melts out, and that the planet surface is kind of used to operating in a certain way. And when we change it, change the snow cover, actually we affect the way that the planet's surface can accommodate that type of behaviour. So it is actually quite serious when we're talking about the changes in snow. When we're talking about changes in frozen water. Also, what we're talking about, and especially in the Arctic Russia is changes to the permafrost – that permanently frozen ground in Siberia and other places, which is starting to melt out. And that melt out is having significant consequences for infrastructure, for roads and buildings that are laid down on what they think is solid frozen ground that’s turning out not to be. And also the release of methane stored beneath the permafrost sealed away from the atmosphere by the permafrost. But as the permafrost melts away that methane can get into the atmosphere.

SS: So let's talk a bit more about that because I came across this thing in Nature magazine, which said that, on the other hand, severely cold winters will be one of the harshest effects of global warming. And that kind of made no sense to me. Can you explain this paradox?

MS: Yeah, absolutely. So in the United Kingdom a couple of years ago, we had something that we called ‘The Beast from the East’, you probably didn't hear about it. But it was a very significant shock.

SS: That’s usually how they call my country. 

MS: It was a shock. It was a lot of cold weather that hit the United Kingdom around about February a couple of years ago. And the reason for that is that we usually get weather systems from the North Atlantic, and those are quite stormy, they've got a lot of water in them. So our winters are usually quite mild and wet and windy. But what happens sometimes is the storm tracks go to the north of Britain across the Norwegian Greenland sea and into the Arctic. Now in the Arctic, there's a high pressure zone, which forbids those storms from going further north. And so because they are forbidden from going further north, we get them in Western Europe. But last couple of years ago, what happened in the Arctic with that high pressure zone didn't form in the way that it should have done. And so the storms went far further north, they went into Svalbard and into the Norwegian Arctic, causing those places, which should be in permanent darkness in February should be minus 15, minus 25 degrees centigrade. And it was raining, they were having plus zero degrees of weather in those conditions. So what happened to that high-pressure Arctic weather, it drifted further south, and it went across Europe, and the easterly wind picked up across very cold continental Europe and came further west toward the United Kingdom. So as a consequence of changes in the Arctic, the Arctic essentially received the weather that the United Kingdom would have otherwise got, and we received the Arctic weather. So these are alterations to the atmospheric system, that is a consequence of large scale global warming, and we're just going to have to get used to seeing more of that type of thing unless you do something about it.

SS: So when you mentioned in a previous question about the Arctic slowly melting, this is also one of the consequences that we could face in terms of climate change if nothing is done. And that would be a huge challenge for our flora and fauna. What plants and what animal species do you think will be gone first, first of all, if we don't do anything?

MS: Well, we know that we've lost a lot of species already. So there's not as if it's something that's new to us. There are pressures on the land, not just in terms of climate change, but also the way that we use land and the tearing down of forests as well has huge effects for biodiversity. There are stresses on pollinators, on bees and insects as well as there are on large mammals as well as across the animal kingdom. There is pressure on many things. And as we get global warming, what we also see is a drift in plants, because they are able to start living in places where they haven't traditionally been in before. Now usually when climate change happens, say, between an ice age and coming out of an ice age, the last ice age was 20,000 years ago, and we came out of an ice age by 10,000 years ago. So we had 10,000 years to warm the planet up. And that's quite a long time. And there was a lot of migration of plants and animals. And again, it took about 10,000 years. So it was a lengthy amount of time to accommodate that. Well, the equivalent changes of a glacial-interglacial cycle, 10,000 years normally, in terms of carbon dioxide concentration, which is 100 parts per million, we're doing that in about 100 years. So the rate of change in our planet as a consequence of burning fossil fuel, and measured increases in the concentration of greenhouse gases is far quicker, near to two orders of magnitude quicker than the planet is normally able to accommodate it. And so when plants start moving, is the land able to accommodate that rapid shift? It's not like when you're planting a tree in the soil, it's the microbiology, the small microbes in the soil that really allows the trees to thrive. And although trees might be able to migrate quite quickly, it's a really unknown question about whether the microbial communities which are so important to the development of plants, whether they are able to shift at the same pace as well. So we're performing in a very unusual experiment on our planet, changing it more rapidly than it's ever been changed before with profound consequences to the way that plants and animals and ourselves live on it.

SS: So these days, we can predict where and when a hurricane or a tsunami is going to hit several days in advance, mostly. But they still bring such destruction and so many deaths. Now, you and your colleagues keep saying that climate change is going to make the weather unpredictable and completely erratic. Are we going to be able to predict any kind of natural disaster at all here?

MS: Well, in terms of weather, we're able to predict extreme events several days before they can hit. So I happened to be in Texas, when Hurricane Harvey hit landfall at Corpus Christi in southern Texas, and a huge wave of water, a spiral arm of the hurricane system landed over Houston (I was in Houston at the time) and deposited a huge amount of rain. Now, about four or five days before that actually happened there was an extreme weather warning for both places and the whole of Texas, and it was predicted remarkably well by the numerical models that were employed to do just that. And that's actually quite a good thing to observe. Because we understand the physics of the atmosphere really well. And we have a lot of data on the ocean where hurricanes acquire their heat that feed into the models, so that we’re quite confident that we're able to predict how these systems are going to affect us. So when you think about it, we have 4-5 days of warning. Now, you might argue that the way that we react in those 4-5 days needs to be improved because a lot of people were severely affected by that storm and other storms around the world. But our ability to forecast extreme events is getting better, not worse.

SS: Scientists have recently found in the Antarctic the prints of leaves that grow only in warm regions like plane trees and beeches. Does that mean that in ancient times the climate in the Antarctic was similar to the Mediterranean?

MS: Well, we can take a history through geology, if you like. So, essentially, from about 55 million years ago, when the level of carbon dioxide concentration was 1000 parts per million, at that time, there was no ice in Antarctica at all, and the global temperature was about 8 to 12 degrees warmer on average. And in the polar regions, it was double that, so over 16 to 20 degrees centigrade in the polar regions. And there was no ice on Antarctica at all, it was covered by trees. Quite a beautiful place, right? But since 55 million years ago, essentially the level of carbon dioxide in the atmosphere has been coming down and down, gradually getting lower. And it's becoming colder as a consequence of that. At about 14 million years ago, Antarctica separated from South America and got encapsulated by a very strong ocean current that wraps itself around the continent and isolates it climatically from the rest of the world putting it into the really deep freeze. And since 14 million years ago, essentially, we've had a persistent deep, thick ice cover over Antarctica. Now, the reason that we talk about geological time and the reason it is important to us, is because as I said, previously, the last time we had 400 parts per million of carbon dioxide was 5 million years ago. If we keep emitting fossil fuels in the way that we're currently doing it, by the end of this century, by 2100, the level of carbon dioxide in the atmosphere will be 1000 parts per million. We wouldn't have seen that level of carbon dioxide for 55 million years, and when that last happened, there was no ice on the planet; and as you said, Antarctica had plants and trees living on it. So the consequences will be a sea level globally of about 60 meters higher than it is today and very warm conditions. Now it might take several centuries or millennia to get to that point. But the lesson from the geology is quite straightforward. When you get 1000 parts per million of carbon dioxide, the world changes unrecognisably from what it is today.

SS: So the world, like you say, used to be pitted into East and West camps, but really it could be seen as divided between the South and the North, right? Northern countries fare much better and they are more developed, technologically advanced, richer, and they used to own the South too. So with climate change hitting the South first of all will that sort of division never be breached? Will the South just be thrown back hundreds of years by natural disasters never to recover?

MS: Well, I think, global warming is just going to affect us all. There is a concern that it's the poorest countries that might suffer the most, largely because some of them are living at quite low levels close to the sea, and they will experience land loss and population migration. But also because they're so poor, they don't have mitigation and adaptation strategies available to them in a way that some developed countries might be able to do. So there is a notion of climate justice: the poorest countries in the world didn't cause this problem but they’re on the front line of receiving the effects. But I wouldn't say it's a North-and-South thing. Global warming will affect the entire planet in different ways. For example, when the ice sheets start to melt, when the Greenland ice sheet melts, and when the Antarctic ice sheet melts, and we're seeing the start of that right now, sea level goes up all over the world, potentially by meters.

SS: So by 2050, when you said we should completely put the carbon emission to zero, more than half of the world’s predicted population will lack drinking water. How are we going to deal with that? Will science find a way, or are we headed towards water wars?

MS: You're absolutely right. So we have a lot of stresses on the planet right now. They're all caused by us, all caused by humans, but in different ways. So we look at global warming. And that affects things like extreme heat, and flash floods, and potentially our ability to grow crops. When we’re looking at the availability of water, that is impacted by climate change, but also the overuse of fresh water on the planet right now. For example, we are depleting groundwater – water stored beneath the surface of the planet, that takes centuries, sometimes thousands of years to build up. And we're depleting them in decades. If we run out of that groundwater in some places, it's going to take a very long time for it to be refilled. So there's a lot of water on the planet. And we need better ways to manage that water. And that will be through reservoirs, it will be through using less water, and possibly we can desalinate water as well, especially if we have efficient ways to do that, coupled with electricity generated through solar panels. So there are lots of ways in which we can look after the water on the planet. But we need to do a much better job than we're doing at the moment.

SS: Many ecologists and people who know the subject, including yourself, are basically saying that we have the next decade or so to do something about climate change. And this would, realistically speaking, require a complete transformation of our mentality; because you're right, it's not the governments only, it’s the people and businesses. It's our basic ways of life. And you know, old habits die hard, right? From what I see, we're usually reluctant to abandon comfort and habits for something we won’t feel or see right away. And you're saying it may take a couple of centuries until all ice melts, and sea levels rise to 60 meters high from now. So can we really change within the next 10 or 15 years now that we've been destroying and depleting planet Earth over the last 150?

MS: Absolutely, yeah, we really can. And so let's look at the way that we live right now. And think about the developed countries that we're all part of, and think about the way that we live our lives. And some of the things that we take for granted. And you think about warming of our homes, and food and all these sort of things. But think about it a slightly different way. Think about the quality of the air that we're breathing, especially in cities, London, in particular. Now, the air quality is illegal, especially in the wintertime. And that's no good for our health. Now, we have a right to be breathing clean air. And so with a low carbon transformation and the development of renewable energies and clean energies, that won't happen, we'll clean up the air in our cities, the cities will be nicer places to live. And when we talk about using less energy. It might mean insulating your homes better. It might mean taking the thermostat down a notch or two, so it's not boiling hot in your homes, but it's just a little bit cooler. But then you get cheaper energy bills as well. And I'd say to people when they're nervous about this transition, who doesn't want to have clean air? The damage that it's doing to your health and your children's health is profound. And who doesn't want to have cheaper energy bills? So the future, this transition that we absolutely need to undertake we shouldn't be fearful of. It will be different, but there are many positive effects to this, and in particular, importantly, to our own health.

SS: All right, Martin, thank you so much for this insight. We were talking to Professor Martin Siegert, glaciologist and co-director of the Grantham Institute for Climate Change in Imperial College London discussing global warming at what we have to get ready for in case we fail to deal with it. That's it for this edition of Sophie&Co. I'll see you next time.