With great sadness, we share the news of the passing of our friend and colleague, Dr. Will Steffen. A leading thinker and steadfast advocate for climate action, Will is remembered by those close to him for his kindness, generosity, and courage. He was a true pioneer for climate action and earth system science and was dedicated to helping the world understand climate change. Will’s legacy will live on in the work of his family, friends, and colleagues. In Will’s honor, we are republishing our 2020 interview.
Common Home Conversations: Will Steffen
Interview Transcript
Transcribed by Otter AI
Kimberly White
Hello, and welcome to Common Home Conversations. Today we are joined by renowned climate change expert and earth system scientist, Will Steffen. Will is an Emeritus Professor with the Fenner School of Environment and Society at Australian National University. He also serves as a Councillor with the Climate Council of Australia and as Co-Chair of the Scientific Committee of the Common Home of Humanity. Thank you for joining us today!
Will Steffen
My pleasure.
Kimberly White
So Will, what does it mean to be an Earth System scientist? What are you currently focusing on?
Will Steffen
Well, an earth system scientist is someone who studies our home planet but studies that as a single, integrated system. And that’s a relatively new area of science because the natural sciences, in general, like to look at pieces of a system, pull them out and study them in great detail. Whether it’s pieces of an ecosystem or part of the climate system, you might be studying what’s happening to the ice sheets or what’s happening to ocean circulation and so on. And so that’s the way natural scientists have worked for decades and centuries. But in fact, a new area of science called complex system science has been developing, trying to put the pieces back together and understand how systems work as complete systems. And they have things like emergent properties, things that you can’t understand just by looking at the pieces of the system in isolation.
So now we’re applying this sort of thinking to the earth as a whole. And we call it the Earth system because, in fact, it has properties that are characteristic of the earth as a whole. And it has processes that change these properties. Now, in a practical sense, that means that as we look at the earth system today, it’s changing very rapidly. It’s moving away from an 11,700-year, very stable state, which we call the Holocene, or the geologists call the Holocene, and it’s moving away from that at a very rapid rate because of human pressures. So we’re trying to understand what it is that is driving these enormous changes. And there are many interesting ideas here.
One of the most important ones are tipping points, which are parts of the system. When you push them, they appear to be resistant to change; when you push them just a little bit too far, they can flip or move into another state. Some of these are linked to form what we call tipping cascades. So this really is, if you like, the engine that’s driving changes to the earth system. So we need to understand low, gradual changes. But we also really need to understand how these tipping points may lead to more rapid change and changes that will be very hard to reverse. So just in summary, what Earth system scientists try to do is we’re trying to understand our planet as a single complex system, one that has its own properties at the planetary scale, and one which is being pushed very hard by human activities. So basically, that’s what we’re trying to do.
Kimberly White
That is very impressive- it sounds like a fascinating field of study. I know that there are some in the scientific community that have stated we have entered the Anthropocene due to the building pressures from humankind, and you mentioned tipping cascade points. Can you elaborate further on this?
Will Steffen
Yeah, I can give a common analogy in everyday life if, say, someone goes out on a lake with a kayak and is paddling around, you can jiggle that kayak a little bit, then it returns and it’s upright, you can paddle alone. But if you tip it too far, it flips all the way over, and you’re underwater, and you’ve got a scramble to get back to the surface. And that’s a tipping point, almost literally; you’ve tipped it past the point of no return, and the kayak flips. So that’s a very simple analogy toward parts of the earth system, which simulate similar behavior.
A good example of that might be the sea ice that is floating over the Arctic Ocean. So how does that work? Well, in the Northern Hemisphere, in the summertime, there’s a lot of sunlight over the Arctic Ocean. But if it’s covered with ice, that white ice reflects the sunlight, affects virtually all of it, and helps keep it cool. But as the earth is warming and summertime sea ice is shrinking, it doesn’t cover as much of the Arctic Ocean. So as it shrinks, it uncovers darker ocean water that absorbs more sunlight, obviously, than the ice does. And it adds to the regional warming over the North Pole. And, of course, as the North Pole warms more, the ice shrinks more. And as the ice shrinks more, it warms more. So you see what we call a feedback loop.
So a lot of these tipping elements have these feedback loops. And the point here, what’s the tipping point? The point is once the ice shrinks far enough, you cannot stop the process. In other words, that feedback loop will take it all the way to an ice-free Arctic, no matter what we as humans do. So that’s a good easy way to understand an example of what a tipping point actually is. There are other ones associated with ice, too. If you look at the Greenland ice sheet, that’s that big massive mound of ice that sits on top of the island of Greenland, that’s starting to melt, and it’s melting at an increasing rate. And one of the important processes there is that as it melts, it gets lower. And as it gets lower, it moves into a warmer climate, which makes it melt more, and then it moves even lower. And you can see again you have an internal feedback that this is going to cause the ice sheet to diminish very rapidly no matter what we do.
I’ll give you one more example of an individual, a tipping point, one that isn’t associated with ice, and that’s the Amazon rainforest. That’s that big rainforest, beautiful forest in the Amazon basin, the biggest tropical forest on the planet, but that is now being threatened by two interacting processes. One is direct human deforestation. And that’s obviously involved with politics. It’s involved with globalization, big investment companies investing in deforestation and conversion to soya or beef, and so on. And what that does is it reduces the recycling of water in that system. So basically, as the name indicates, it’s a rainforest. So it needs a lot of rain to be a healthy forest. This rain comes from two sources. One is evaporation from the forest itself; it’s got its own recycling system. So roughly half its rainfall is actually generated by the forest itself. The other half comes in from the Atlantic Ocean, so it’s moist climate weather systems rather than come in and drop rainfall. So it’s about 50/50. So as we deforest more of that tropical forest, we are reducing the amount of internal recycling of water via the evaporation from the forest. At the same time, the Atlantic circulation is changing because of climate change. And that’s reducing the rainfall coming in from the ocean. So the Amazon forest is hitting a double whammy. So it’s going to hit a point where it doesn’t get enough rain, and it starts burning more often, and that reduces the internal cycling even more. And it becomes a self-reinforcing feedback again, this idea of a feedback that will convert the forest or most of it into what we call a Savanna, a sort of woodland grassland, a much drier system.
So there are three examples of what tipping points are and what internal feedbacks are. Now, the word cascade comes in here too. And that’s because a lot of these individual tipping points or tipping elements are actually linked. The ones I mentioned are actually good examples of that. Because as you lose more Arctic sea ice, it causes regional warming, and regional warming increases the loss of ice in Greenland. What happens to that ice that’s melting on Greenland? Well, it flows into the North Atlantic Ocean. And it’s cold, and it’s fresh water. So it sits on the surface of the North Atlantic, and that actually slows down the North Atlantic circulation, which in turn reduces the rainfall over the Amazon. So the fact that we are losing sea ice over the Arctic is influencing what happens in the Amazon. So I could go on and on; we’ve met quite a few of these tipping points. They operate in most parts of the planet, and many of them are linked. So the interesting thing is when you start looking at these linkages, you can see that you could get up a global tipping cascade initiated sometime in the future, which basically would take the earth system out of human control or influence, and it would move to a different state, probably a much hotter state than we’re anticipating and one with very different rainfall regimes. So this is why tipping points, feedback processes, and tipping cascades are really central concepts that we need to understand how the earth system operates and how it’s changing.
Kimberly White
It really is quite concerning that we have already met several of these tipping points and are on the path to meeting more. Rampant deforestation is a problem we see globally, but especially, as you mention, in the Amazon. Last year, it was estimated that the Amazon rainforest lost an area the size of a football field every minute. There have been some recent studies that have shown that deforestation is leading to more disease outbreaks in humans. This brings me to my next question. One of the main topics of 2020 has obviously been the COVID-19 pandemic. The wildlife trade has been linked to the ongoing coronavirus pandemic as well as several other major pandemics and epidemics in past years, including SARS, MERS, and Ebola. The trade has also aided in the transmission of pathogens that cause bird flu, swine flu, and more. Are there connections between COVID-19, climate change, and environmental disruption?
Will Steffen
There has been some work on this, and it’s more broadly called the connection between biosphere degradation, which is another word for environmental change or disruption, and the so-called zoonotic diseases, diseases that jump from animals into humans. And, of course, this is what’s happened with COVID-19. And for some of the other diseases, as you mentioned, the link there is that as we continue to degrade the biosphere, that is, deforested areas, disrupt ecosystems, and so on. It increases the probability of these diseases jumping into humans because humans are now coming into much closer contact at the deforestation fronts, with these ecosystems which are being disrupted. That’s research in its early stage. And I think we need to do more of that to try to pin down exactly what the connection might be. I think the connection with climate change isn’t as direct as that was, as it is with environmental degradation. That’s the more direct link. But in terms of complex systems, climate change can actually exacerbate also environmental degradation or disruption. And in that regard, it could also be a contributing factor by increasing droughts, increasing fires, and so on. So again, this is a really good example; I think of a very complex set of interactions that eventually link very dangerous diseases to humans. But ultimately, it’s pretty clear that if we have a stable climate and healthy, intact biospheres, we actually do reduce the risk of these so-called zoonotic diseases like COVID-19. So yes, there is a link. I think it’s a fairly complex link, and it’s one that we actually need to study a lot more before we understand it in great detail.
Kimberly White
So essentially, everything is connected. You’re based in Australia, which has been sort of a ground zero for climate change. As much of the world has seen, Australia experienced devastating bushfires in the past year. Climate change has also significantly impacted the Great Barrier Reef, where there has been massive coral bleaching. Can you tell us more about some of the adverse effects of climate change that you see in Australia?
Will Steffen
Yeah, we’ve had a pretty horrible summer, so our summer 2019-2020 summer, our summers go over two calendar years from December through February. But what we saw is an enormous increase in both the area burned and the intensity of these fires. Our eucalypt forests are fire-prone anyway; fire is a natural part of those ecosystems. On an average year, about two percent of the Eastern Australian forests burn; this past season, 21 percent, a tenfold increase, burned. The season started much earlier. So it was actually starting in August and September up in Queensland, which is just as when winter is ending, and then it moved down the coast as the summertime conditions came into play in New South Wales and then down in Victoria. But they burned for many months. The intensity was enormous. They caused their own fire weather. We had firestorms and tornadoes caused by the fires themselves. They were so disruptive and so damaging that one of the aircraft that is used for fighting fires, in fact, unfortunately, it was some Californian firefighters who came across to help us, but they weren’t familiar with the intensity of the fires that are generated over here. And unfortunately, they got caught in a tornado, and it took their C-130 down, crashed, and killed all three of them. Overall, fatalities were between 450 and 500 people killed. Much of that was by smoke inhalation, and about 35 to 40 were directly burned to death. Three billion animals, kangaroos, koalas, and other marsupials were burnt to death. Pretty horrible way to go. And a lot of there was a lot of psychological damage done to humans both from the fires themselves from having to evacuate several communities along the coast. We’re actually isolated and pinned against the ocean by the fires, and they had to be rescued by the Navy. There was no way they could get out.
Here in Canberra, which is the capital city, we’re a city of about half a million people. We aren’t on the coast; we’re embedded in forests up inland. And we had a very dangerous situation. We had a big fire front coming in from the south, and it came within about ten kilometers of the southern suburbs, and we were put on alert to evacuate the city. Three major roads come out of Canberra, but two of those were already cut by other fires. So we were facing the potential disaster of not being able to evacuate our city with enormous fire coming in. Fortunately, the wind shifted last minute, and we were spared. But this sort of traumatic event was played over and over again right along eastern Australia. The estimates by the medical people or health experts were that well over half of the entire Australian population was affected negatively by the fires either psychologically or directly physically. So it was a massive event that we weren’t prepared for in any way.
Now, you might ask, what’s the connection between climate change? And there are some pretty strong connections. We just had a couple of extremely hot years; the hottest year on record, 2019, was well above average-temperatures. And at the same time, many of the areas in which these forests grow had been subjected to several years of very dry conditions, well below average rainfall, and severe drought. So basically, these forests were just set up as a tinderbox, a massive 3000-kilometer-long tinderbox. And when it took off, there was no stopping it. Some colleagues of mine who are professional firefighters said they’ve never seen anything like these conditions that they had no way of controlling. They just had to turn and run for their lives as well. So it’s by far the most traumatic and dramatic catastrophe that we have seen here in many, many decades.
But the interesting thing you mentioned was the Great Barrier Reef. We were so focused on the fires and surviving the fires and coping with them that sort of in the background, sort of quietly, the worst mass bleaching event that the Great Barrier Reef has ever experienced was occurring at the same time. So the Great Barrier Reef is the largest marine organism or ecosystem on the planet. It stretches for 2,300 kilometers along the coast of Queensland and up toward New Guinea. This was the first time that all 2,300 kilometers had been bleached. We had severe bleaching events before. In fact, in the last five years, this was the third extreme, severe mass bleaching event. The upshot of this is over half of the Great Barrier Reef is now dead. So 50 percent or more of the hard corals are actually killed and not just bleached; they can’t recover. And so the reef is in a very bad condition at the moment. And unfortunately, sea surface temperatures are predicted to continue to rise for at least a couple of decades that’s built into the climate system. So the prognosis is not very good at all.
I think what we’re trying to do down here is to hopefully stabilize the climate within the Paris target range. Hopefully, we will retain some remnant reef; some small fraction of the reefs will still come through that, and then we can try to regrow and recover as we stabilize the climate. But just in summary, the summer of 2019/2020 was something that was way outside anything we had experienced in decades, or perhaps ever here, in terms of the ferocity of the fires, the damage that they did, the enormous areas that were burned and the same time off the coast in the water. Enormous bleaching event on the Great Barrier Reef. So if we ever needed a wake-up call that the earth system was getting out of control, this was it.
Kimberly White
Absolutely heartbreaking- I cannot even begin to imagine the scene there in Australia. I saw some of the media coverage showing firefighters out there bravely risking their lives as well as the aftermath, showing the impacts on wildlife and the environment. So Earth System science seems to create a new way of thinking about ourselves and our relationship with our planet and how it is all connected, which kind of ties into what we were talking about. Do you think that this requires a fresh legal approach that is scientifically friendly and has a better capacity to explain this highly connected way of functioning?
Will Steffen
Yes, I think that’s a very good point. And what are the problems we’re facing in dealing with climate change and dealing with biosphere degradation, like what’s happening in the Amazon, or in other parts of the world where it’s direct deforestation and degradation of ecosystems, that shows you that we have a huge legal void in how we manage ourselves and our relationship to the earth system? And, of course, our legal systems are built on the nation-state idea that’s been around for 200 or 300 years. And we have extremely weak global governance. We have the United Nations; they try to do the best they can. But it’s still dominated by nation-states and their own self-interest. Now, that might work when we humans were a small world on a big planet. In other words, when there were many fewer of us, we didn’t have the powerful technologies we do today and so on. We could live within the limits of the earth system, and we did for hundreds of thousands of years. But now, in 2020, it’s a massively different situation. Now we are a big world on a small planet, and that changes the game entirely. We completely lack the legal instruments and legal framework we need in this new situation of the 21st century.
So basically, Earth System Science, I think it’s the scientific underpinning that’s required to build a new legal framework. Because Earth System Science says that we are on one planet, which has one single life support system. So it’s always very important to say Earth system in the singular, not Earth systems, but Earth system. So that really then translates into our common home; it is our home. There’s no way we’re all going to move to Mars or somewhere else. This is it. So we have to learn to live within the characteristics and limits of our planet as a single system. So the idea of the common home is the very first step to getting governance that is consistent with our system science, with what the earth system is actually telling us. It means we actually have to recognize that legally; it doesn’t yet exist legally; nation-states do. Australia exists as a nation-state, so does the United States, and there are about 200 of us around the planet that exist as nation-states. And we somehow try to muddle through governing the earth system. We have some regulations about what can be done in oceans, but then nation-states claim oceans, ocean economic zones. So we claim parts of the earth system and then fight over who has the right to fish in those or whatever. So it’s a very incomplete, incompetent system from an earth system perspective.
So the first thing we have to do is recognize the earth system as our common home. So we have to legally recognize a system, an intangible system. So we recognize territories; we recognize the continent of Australia. North America has three countries- the United States, Canada, and Mexico. They’re defined. There is a border where Mexico ends and the United States begins, and so on. So it’s divided up. But you can’t do that with a system. You can’t divide up ocean circulation, or atmospheric circulation, or the movement of carbon. That doesn’t work. So we need to think of the software. Now obviously, that’s hard for people to get their heads around. But legal people say we actually have precedents. We can actually do this. For example, we recognize copyright. So I’ve got lots of books here. I’m talking to you; I have a bookshelf up here; there is a physical book, it’s made of paper, and it’s got print, it’s got ink on it, that is the physical book. But in fact, the real value of that book is the ideas that are in that book, and that’s intangible. And I only get that through my own brain and interpreting patterns on pieces of paper. So the same thing with the earth system; there is a physical ocean, and there are physical bits of land, but in fact, it’s the system. It’s the circulation. It’s these tipping points. It’s the long-term changes, the long-term patterns of stability, that actually make the planet habitable for humans and the rest of life.
So I think it’s an extremely important legal step that we have to do to say, alright, this is our home planet; it has to be recognized legally as a system that we all depend on. And it’s in our common interest to keep this system in a well-functioning state. So I think that really is the challenge in front of us now in terms of the legal challenge of recognizing the earth system.
Kimberly White
Absolutely. And climate change doesn’t recognize borders. It doesn’t matter if you are in the United States, Canada, or Australia- it is happening now, it is happening everywhere, and it is happening at an alarming rate. For the sake of our global community, we need to do better. You’re a part of an organization that is really working to make a difference in this. You are on the Scientific Committee at the Common Home of Humanity. Can you tell us more about this organization and how it can better address climate solutions?
Will Steffen
Well, the Common Home of Humanity is an organization that’s designed to recognize the earth system as a single integrated system and push very hard for legal status. So, in other words, a global legal pact that recognizes the earth system, the software of the planet, and I think, to make that work in a legal sense, we need to have scientific backup. Because this is a new concept to a lot of people, it’s a new concept, particularly to people who are not natural scientists who are in the legal profession, politicians, economists, or other people in other spheres of academia or in politics, policy, and so on.
There needs to be a solid scientific background that, first of all, understands the earth as a single system, but really importantly, understands how this system operates. Because it’s not an even system. For example, the Amazon rainforest is extremely important for how the entire global system works. So who’s responsible? It sits in nine or ten South American countries, with much of it in Brazil. So to understand how important that is, you actually need to understand the science of how that system actually operates, that rain forest system, how it metabolizes carbon, how it affects the climate, how it is affected by the climate. And this is what a common home is about, is that if we deforest the Amazon, it’s actually going to affect rainfall over Australia, it’s going to affect temperature over China. And we know this from global circulation models. This is what’s going to happen. So it’s in Australians’ interest to have a well-functioning Amazon, just as much as it’s in Chinese interest to have a well-functioning Amazon. And also, of course, for Brazilians and South Americans. So, to understand that and understand that we need a legal regime that recognizes this, you need the scientific underpinning as well.
So I think this is a really, really good example of how the natural sciences can work with the legal profession, and ultimately, hopefully with economists, political scientists, and so on, to recognize our common home and then build. Hopefully, we get legal recognition of the earth system as a system and then build on that in terms of policies in terms of economic instruments that can help us reestablish the Amazon forest, regenerate forests and ecosystems elsewhere, and protect ocean circulation. The basis for all of this has to be that we legally recognize our whole planet as our single common home.
Kimberly White
We are all global citizens, so these shared assets really concern everyone. As a scientist, what actions do you think must be taken right now to overcome the obstacles that have prevented us from reaching a global agreement?
Will Steffen
I think there are a number of things that have to be done. Straight away, I think we need to get recognition of the common home legally. The best way to do that, I still think, is through the United Nations system. It’s going to take some effort, but I think just opening up the conversation is going to be really, really important. Perhaps the steps on that way, we need to develop some sort of legal recognition, for example, of the Amazon forest, and ways of managing it. So we need to, for example, interact with the finance sector. And I do some of that myself as an expert working under the Common Home of Humanity banner. We’ve talked to some of the big finance companies which are funding a lot of the deforestation, and a lot of them don’t recognize the implications of what they’re doing. They simply look at it economically, as alright, is this a good investment? Will it return money for our investors and so on? But when they’re made aware of what’s happening, not only just in Brazil but how this is influencing how the entire earth system works, that’s something entirely new.
So I think what we need to do now to overcome those obstacles is we have to have a multi-pronged approach. We have to work hard on the legal aspect that needs to go ahead through the UN system and so on, but at the same time, we need to engage critical players in how the earth system is being degraded, the finance sector, the fishing industry, things like that. These initiatives are happening; we are starting to engage with these sectors. And so, obviously, the fossil fuel sector is a very big one. It also tends to be a very resistant one compared to, say, the finance sector or the fishing sector, which are actually more open to talking about this. Perhaps because they’re more closely related to the implications of damage to the systems they depend on. Fishing is a good example. Again, this is a global commons. The fish don’t recognize zones that humans have artificially put up in the sea waters. So we need to manage as a common collective good, the fish in the ocean. And enlightened fishing companies are now starting to realize that they actually have to work together and not compete to actually protect the fisheries in the ocean. The same thing started to happen with some big finance companies understanding that if they undermine the Amazon forest, they’re going to lose their investment, it’s going to become worthless, as rain drops off and you can’t grow soy, not enough grass for the cattle, they’ll be in trouble.
So I think that this two-pronged approach of, you need the big overarching common home legal recognition, and that’s starting to happen through the UN system; we hope it comes to a positive conclusion. But at the same time, there are parts of the earth system that we can start tackling, using this common home idea and concept and framework to help us deal with some of these big issues. So, fortunately, things are starting to move. We’ve got a long way to go. But I think we’re making some inroads. The biggest thing we have to do is change how people think, how they conceive of the planet, how they conceive of their actions, and the reverberations those actions have through the earth system. So it’s an exciting time to be in this area of research. We’ve got a long way to go. But I think we’ve got an extremely exciting idea. And we’re making good progress.
Kimberly White
Well, there you have it. Earth system science- a new area of science that gives us a new way of looking at our planet and how the Earth System is highly interconnected, functioning as a single integrated system- connecting us all. As you said, Will, we still have a long way to go, but the Common Home of Humanity certainly provides a beacon of hope moving forward. That is all for today, and thank you for joining us for this episode of Common Home Conversations Beyond UN75. Please subscribe, share, and be sure to tune in next Wednesday to continue the conversation with our special guest, Maria Espinosa, President of the 73rd Session of the United Nations General Assembly. And visit us at www.ThePlanetaryPress.com for more episodes and the latest news in sustainability, climate change, and the environment.
