SCIENCE AT THE SHINE DOME canberra 7 - 9 may 2008
Symposium: Dangerous Climate Change: Is it inevitable?
Friday, 9 May 2008
Professor Will Steffen
Director, The Fenner School of Environment and Society
Will Steffen was born in the USA and has a degree in chemical engineering from the University of Missouri. He has a masters and PhD in chemistry from the University of Florida. Following a research fellowship at the Research School of Chemistry at the Australian National University (ANU), Will joined the CSIRO Division of Environmental Mechanics in the roles of science management, editing and communication. His research interests include terrestrial ecosystem interactions with global change, the global carbon cycle, incorporation of human processes in Earth system modelling and analysis, and sustainability and the Earth system. He was executive director of the International Geosphere-Biosphere Programme for six years, based in Stockholm, Sweden. Will returned to Canberra to a visiting fellowship with the Bureau of Rural Sciences, and was later appointed director of the Centre for Resource and Environmental Studies (now the Fenner School of Environment and Society) at the ANU. He also became science adviser to the Australian Greenhouse Office, a position he still holds. He serves on a number of advisory panels and is a member of the Academy’s National Committee for Earth System Science.
A new geological epoch, the Anthropocene
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Thanks very much, Mike. I also must admit to being a child of the Anthropocene, but a bit more specifically, as you will see in a few minutes, both Mike and I and many of my colleagues out there are children of the Great Acceleration, which is a particular phase of the Anthropocene.
I would like to give you this talk in two parts. I will just describe why we are calling this a new geological epoch, the Anthropocene, and then finish with some comments about what it means for the future, in terms of these big issues that you sometimes hear about: sustainability, collapse or somewhere in between.
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This idea of the Anthropocene era – and most of this talk – is based on a paper that I wrote with two colleagues, Paul Crutzen, an atmospheric chemist, and John McNeill, an eminent historian of the 21st century, and it drew on some earlier work of Paul's and also some earlier work we did in a Dahlem conference.
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The idea is fairly simple, that humans have now become a geological force in our own right, as large as or larger than some of the great geophysical forces that shape the environment of the surface of the planet.
People have argued that for a long time humans have affected environment, and that is true. You can go back to the fire-stick farming debates about the hunter-gatherers, the megafauna extinctions and so on, and indeed you can see evidence of human activity at local and regional scale thousands and tens of thousands of years in the past. But you cannot find any discernible effect of these early humans on the functioning of the Earth system at a global scale. Put simply, we were below the radar screen, and the great forces that drive changes in climate, in ocean and atmosphere, in the biosphere and so on were pretty much operating as they do, with a reasonable degree of natural variability.
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But all that has begun to change. I won't talk much about climate, because a lot of my colleagues have said a lot more about it. I do want to show this figure, though, because this puts it into a long-time perspective.
This is a near-2000-year record of northern hemisphere surface temperature. (We don't have one yet for the southern hemisphere; we are working on it.) You can see in these coloured lines that there are various ways we can reconstruct, using different proxies, what climate was like. And you can see a lot of variability in there. But that red line at the end is the instrumental record, and you can see that on that time-scale something different is indeed happening over the last century or so.
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We have all seen a lot about Arctic sea ice, so I won't talk any more about that.
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What I do want to say is that climate is not the only thing that has been changing rapidly in the Anthropocene. In fact, I would argue we have more directly affected the natural world, the ecosystems, and the biosphere than we have climate to this point.
This is one good example from the marine sphere, the famous Newfoundland cod fishery. You can see that back in 1800s or so there was a small increase in catch as people learned how to do things better, but then after the Second World War there was a huge spike in the increase in fish stocks taken. Unfortunately, the fishers at that time did not realise they were working with a biological system that had limits. They hit the limits and cod stocks crashed; they recovered a bit and they crashed again. Interestingly, it was only in 1992 that fishing was banned. Notice that it was not banned at the point of the initial crash, which says something about lags in terms of human responses. (I will return to the year 1950. It is quite significant.)
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We have obviously changed the terrestrial biosphere. This slide illustrates quite a common occurrence around the planet: a more natural ecosystem being converted into something that looks more like an industrial landscape. Obviously, these landscapes provide a lot of goods and services for humans, in particular food and water. On the other hand, we lose a lot of services that up to the present we haven't valued when we make this conversion.
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There are other, more interesting, things happening. This slide depicts the flow of virtual water in grains around the world. This is the water embodied in growing a grain crop and then shipping it around the world. Notice that there are two major places that ship their water supplies out to the rest of the world. One is North America and, interestingly, we are the other one, even though we are the driest inhabited continent.
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If you put all that together you get a phenomenon that goes beyond climate change to what we call global change. It has many features.
At the top left is depicted the nitrogen cycle. Notice that 100 years ago a very big piece of the human-driven nitrogen cycle was not even there. That is the fixation of N2, an unreactive gas, from the atmosphere by the Haber-Bosch process, primarily to produce fertiliser. You can see that once you do that, it reverberates through the entire nitrogen cycle. All you need to do is look at the difference in the size of the arrows for an indication of the impacts due to human activity. We perturb the nitrogen cycle more than we do the carbon cycle, even though we focus a lot more on the carbon cycle.
Shown at the bottom left is the number of large dams around the world that impede the flow of rivers to the sea. The only places where large rivers still flow unimpeded are basically in Siberia, as well as in Alaska and Canada.
In terms of land cover change, shown at the top right are the areas of the Earth that are now primarily given over to intensive cropping. You will see that apart from the tropical rainforests in West Africa and South America, the areas which are not converted are either too dry or too cold for agriculture.
And then we have the climate issues we have been talking about. Depicted at the bottom right is the satellite imagery of Cyclone Katrina coming in on New Orleans.
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Finally, we have the very iconic figure of global mean temperature rise since 1850 and beyond.
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We tried to encapsulate all of this in a synthesis we did a few years ago for the IGBP [International Geosphere-Biosphere Programme]. We tried to put together both the human dimensions of global change and the natural features of global change. On each of these graphs we go from the year 1750, to start before the Industrial Revolution, up to the year 2000. This set depicts the so-called 'human enterprise'. So we have population, total economic growth and foreign direct investment. Then we go into some resource use: water, fertiliser and paper consumption. We wanted to get some indicator for globalisation, so we chose McDonald's restaurants. It looks like any other curve that you have seen, in terms of the number of McDonald's restaurants. In transport and communication there has been an absolute explosion since the Second World War.
There is one thing to note. Even when there was an aspect of the human enterprise that was active before the Second World War, the slope of that curve changed after the war. Many things that we take for granted – international tourism, foreign direct investment, motor cars – largely are creatures of the post-Second World War world. This is the phenomenon that we refer to as the Great Acceleration. It is something quite remarkable in the entire history of human existence on the planet.
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We can then look at the globally aggregated impact of this on the environment. These are all global aggregates; they mask very large regional differences.
Shown at the top are the famous greenhouse gases that you all know about. Below them we have ozone depletion. The next two graphs are for the only two that are actually directly physical climate: the Northern Hemisphere temperature and the number of great floods. On the third line is direct impact on ocean ecosystems, in terms of fisheries, the coastal zone, with the amount of nitrogen going through the coastal zone. At the bottom we show the loss of tropical woodlands and forests, and so on.
So you can see that although the 1950 year is not quite so sharp here, things have certainly been accelerating in terms of global environmental change as well, during the last century.
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So what has caused this Great Acceleration? You can read through what the triggers are, but a couple of them I think are very intriguing.
First, network theory tells us that globalisation has probably had a big part in this, in terms of moving around information, finance, technology and so on. But when you look at networks and you start connecting nodes, not much happens until you hit a threshold – a highly non-linear function. When you do, the system takes off in terms of its ability to move things around. We think that happened in the decade after the Second World War.
I would make two other points in particular. One relates to the emergence of 'armies of scientists and technologists' after the war. We had to do something with them; they were shoved into the civil economy. The last point is the 'growth imperative': increasing consumption per capita has become a core value of modern Western society, and that drives a lot of what is behind the Great Acceleration.
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We attempted to make a very simple systems diagram of what is behind the Great Acceleration. This is very simple and glosses over a lot of detail, but basically it is a population–production–consumption loop, just as Mike Raupach talked about this morning. It is driven by energy. It needs energy; it creates more energy. But two things are absolutely crucial. You need knowledge, science, technology – all of us in this room probably play a role in that – in greasing the wheels of this loop. And, importantly, you need institutions and a political economy that make this a smooth loop. All you need do is look at the collapse of the Soviet Union to see that when these things go bad, the loop really slows down.
So all of these elements are important to drive what we call the Great Acceleration.
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Another way of looking at it is to look at what is called the global footprint of the human enterprise – another fairly crude indicator but nevertheless one that tells you the overall story. What we try to do here is to estimate, for each human, how much land and sea it takes to produce the food and other natural resources that you consume, and to absorb the waste that you produce in terms of carbon dioxide, nitrogen and so on. You can aggregate those for 6.6 billion people, and find out how many hectares of Planet Earth it requires. Well, we are now actually over one Planet Earth. We passed the one Planet Earth level somewhere in the 1980s.
You say, 'Well, how can you possibly do that? There is only one planet Earth.' What it means is that you are eating into the capital of the planet. If you are living off an endowment, and you are living quite well off the interest but you decide you want to live a little bit better, you can start eating into the capital and you can live really well for a while, but you are sealing your fate in the longer term. And that is basically what is happening here.
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This is one of the most fascinating plots I have seen recently. This tries to bring together the concept of global footprint with the concept called the Human Development Index, which is a UN indicator, a basket of things like infant mortality, life expectancy, income, education and health. It tries to measure how well off we are in terms of well-being, rather than wealth. We can rate countries by how big is their environmental footprint but how well off is their population.
You see that African countries have a very small footprint, but they are very far below in the Human Development Index. The USA is very high in the Human Development Index, with very good well-being, but it has an enormous footprint. Further down in the same column as the USA is a little dark-green blob, not labelled, which represents Australia.
There is a curve emerging, that as countries develop, they actually slide past the so-called sustainable development quadrant. As they get the Human Development Index up to acceptable levels, they have already exceeded the permissible footprint – if we want to live within one planet Earth. You will note, by the way, that there is only one country in the world that (barely) slides into the very corner of the sustainable development quadrant.
So this, in one figure, shows the sustainability dilemma.
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Let me comment, then, on where we might be going in the future, in terms of sustainability or collapse. The problem now is that we have got this Great Acceleration under way and it has huge momentum. We spent a lot of time at the Dahlem conference trying to think whether there are trends of deceleration, and in fact you can't see many. Even when you look at some of the new technologies, you see that they soon get swamped by the so-called rebound effect: if you use a more efficient technology that uses less energy, you save money and then you go on a holiday in Europe and emit even more CO2 when you fly across the ocean. There are all sorts of examples of this rebound effect, which actually gives you a false sense that we may be decelerating.
This question now of sustainability or collapse has become very topical. Some of you may have read the book of Jared Diamond where he looks at some past civilisations and analyses why they might have made it through an ecological or environmental crisis, and why they collapsed.
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The image here is from a trip I did a couple of years ago to Greenland. Someone referred to this this morning, saying that the climate in Greenland was warmer about 1000 years ago. And indeed it was. This is an example of a ruin from the old Norse colony, which disappeared around 1400 when the climate became cooler. But it wasn't that much warmer. There was virtually no change to the Greenland ice sheet, for example. The Norse lived right up against the Greenland ice sheet. So what we are seeing now, what Neil Hamilton described this morning, is quite a bit different from what was going on at the time they were in Greenland.
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To look at past civilisations: there is a very rich literature in anthropology, in sociology, in archaeology, about what happened to these civilisations. Shown here are three examples where we have put together, on the horizontal axis in each case, a history of a civilisation – the one in East Africa, the classic Mayan civilisation, and a civilisation, the Akkadian, in present-day Syria. The vertical axis is a measure of the wetness or dryness of the regional climate.
You can see that there is a pretty good linkage between periods of well-being in the civilisations and periods of collapse when things got dry. The sharpest one is in the Akkadian civilisation, where the collapse corresponds very, very well to a drop from wetness to dryness.
This is not environmental determinism, for those of you who are social scientists. This is a fairly simple diagram. To unpack this: these societies disappeared for very different reasons, due to the internal dynamics, the internal organisation and the internal complexity of these civilisations. In fact, one of the most intriguing theories for why societies collapse is that they become too complex, that they tend to solve problems by putting in more bureaucracy, more rules, more regulations, more institutions. Early on in a civilisation that is good; it is a good adaptive mechanism. But when they get to a certain point, increasing complexity actually decreases resilience.
Joseph Tainter has written about this, and I would encourage you to read his books. His latest comment was on the response after 11 September 2001, in terms of how we should deal with terrorism. Travel and all sorts of aspects of life have gotten incredibly more complex. Is this really an adaptive response?
So there is some really interesting social theory behind a lot of this.
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Something which we haven't talked about yet but which is staring us in the face is the peak oil issue. Here is a diagrammatical representation of it. The orange circles are the original stocks of oil that were in various parts of the world; the black is what is left. This shows visually that if we haven't hit peak oil already, we are virtually there now. You can also see the geopolitics quite clearly when you look at where the oil is and where the demand is.
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This is another fascinating figure. This is the change in societies and countries around the world toward joining the globalising community, from premodern and so-called modern states. The interesting thing is that the Great Acceleration that I showed you a few slides ago was driven by the 'globalising' part of the population – 20 per cent. (I told you it was a global aggregate.) Now we are seeing large parts of China and India starting their own Great Accelerations. This is something to think about. We have a really big issue on our doorstep, in that they have a legitimate desire to improve the lot of 65 per cent, two-thirds, of the world's population, which is well below the Human Development Index. And yet basically the environmental capacity that would allow them to do that has already been consumed.
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This has led to huge geopolitical tensions, cultural tensions, societal tensions. The illustration here is a very simple version of it: those people who think globalisation is good and will lead to even more growth, against those people who challenge that viewpoint and say we need to change how we think about our place on the planet.
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It is not that simple. It is much noisier than that. A colleague of mine just spent one year looking at newspaper headlines, to capture how the world might be going. You see here some very interesting, completely opposing viewpoints. You have 'Hyper individualism', 'Shared responsibilities', 'Sustainability first', 'Just do it' and so on – you can read all of those. Interestingly, they do fall into the four story lines that the IPCC use to generate their emissions scenarios. But the interesting thing is that it is a very chaotic situation as we begin the 21st century. Those of us in the science and research field think we understand the problem pretty well, but our understanding is not shared by people in the business community or, largely, in the government – or in the general public, at least not yet.
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Other things are happening, though, in terms of 21st century change in environment. Biological diversity, I think, is as important as climate. The extinction rate now, by best estimates, is about 100 times background level. Almost none of that is due to climate. It is all due to human modification of habitat or other stresses such as invasive species. But with climate change kicking in, we are looking to go toward between 1000 and 10,000 times extinction rates this century. Some have called it the sixth great extinction on the planet.
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Sea ice: Neil showed you that much better than I could show you.
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That is the graph showing you what Neil did. This is the envelope of predictions of loss of that sea ice; those are the observations. Again you see that non-linear effect.
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Instabilities in the ice sheets: John Church talked about that.
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And here is the same plot John showed: the overall net mass of ice in Greenland seems to be dropping now by about 250 cubic kilometres a year, by a variety of measurements. So that has all been said.
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If we look into the future, one of the interesting ways of visualising what the Great Acceleration would do this century is to use the 'Night Lights' image, of NASA. (You have probably all seen this.) We can look at that and put it on top of the temperature record.
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Here is the temperature record of the last 1000 years. The black line is the human additional warming during the last century.
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Now we digitise the night lights in the year 2000, and we take an A1FI scenario. This is the A1 IPCC scenario with fossil fuel intensive energy systems. That is the one we are tracking on or above.
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Now let's go to 2070; watch what happens to the lights. This is what the night lights would look like in 2070 if we stay on an A1FI trajectory.
Then we can go forward. We can estimate what CO2 would be, associated with that particular scenario, put that into climate models, and see what we project.
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This is what we get. So that is the pattern of natural variability. I have deliberately and provocatively put this on the same time-scale. So the smooth IPCC curves you see, when put on a palaeo time-scale, look like this.
This is all IPCC projections. The arrows and the comments are my own interpretations; they are not IPCC's. But this is the committed climate change that several people have talked about.
You see the 2° level that Ove Hoegh-Guldberg talked about: large biodiversity loss in addition to the fact that coral reefs will probably disappear. You see the Greenland ice issue, somewhere near 3°, which has also been mentioned. What we have to say here is that the feedbacks that Mike talked about probably kick in at somewhere between 3° and 4°, if they haven't kicked in earlier. And I would argue that when we go to the top end of this scenario, modern civilisation will probably collapse, which is precisely the point that Stern made in his report as well.
As we try to synthesise that information, that gives you in one image, I think, what we might have in store for us – depending on where we go on those scenarios.
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As Mike Raupach pointed out, we are tracking on those upper ranges.
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We are tracking also on the upper range of temperature and, as John Church said, the upper range of sea level. That is not a surprise. If emissions are this high, you expect the climate system to do exactly that.
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We looked at this in my school at ANU and said, 'Why have we not been able to solve these problems?' – biodiversity loss, land degradation, overfishing, climate change, you name it. The problem is this. You can set any sort of sustainability target, and you have got a trajectory going beyond that sustainability target. We seem to be stuck in short-term pragmatism. We can fiddle with the curve a little bit, but we can't turn it over. And that is true for any one of these indicators.
The problem is that we miss the long-term foundational issues, the issues that really force us to question where society is going, where our core values are and so on. That has to underlie how you get a democracy to change. There is an interesting comment someone made, that China was the only country to be able to get its population in order, and of course it is not a democracy.
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The other point is about sustainable development. A lot of people say it is a trading-off of economic, social and environmental values. We argue at the global scale that it is a false way of looking at it; it is a bad concept. At the global scale it is a hierarchical approach. If you change 'global environment' to 'life support system', that is obviously the fundamental thing. If you don't have a global life support system you can't sustain human life. And if you don't have a healthy social system, you can't sustain an economy. The Soviet Union is a good example of that.
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So we are arguing that to solve these problems we need all the technologies, we need an emission trading scheme, but I think we need to go deeper than that and consider our role in the planet during the Anthropocene.
Thanks very much.
Discussion
Question: You made a comment that scientists seem to understand very well what is going on, but others don't. What responsibility, therefore, is there on the scientific community to get the message to others?
Will Steffen: I think there is, and I think we are starting to meet that. The IPCC has been a fantastic tool in starting to do that. It is interesting that we lacked a similar tool in other aspects of global change. The Millennium Ecosystem Assessment started to redress that, but a lot of those other changes that I talked about are basically under the radar screen still. Climate isn't, but the other ones are, and we need to start bringing those out as well and show how they are all linked to the same fundamental problem.
Yes, we do have a responsibility, and we will try to meet that.
Question: The question of energy: to me it seems that energy is probably the driving force behind globalisation in the last century, when we have had cheap oil, cheap transport, and all the energy we need to drive these things. Do you see any feedback loop with the price of oil going up and the supplies of energy becoming more expensive, or do you think this is just going to be peripheral?
Will Steffen: It is going to be a feedback loop but I don't think it is going to be a major one. If you actually look at the emission profile in Australia and globally you see that the biggest one is generation of stationary energy. The second one is probably built infrastructure. The third one is transport. So you could argue that you get a feedback effect from liquid fuels becoming more expensive, but there is a lot of coal in the ground that can be used to drive stationary energy, heating buildings and so on – if we don't change. And that, of course, will continue to drive emissions up. So I would call that a weak feedback loop, and an incomplete one. It is not going to solve the problem, let's put it that way.
Question: I like your idea of the Anthropocene very much. I would like to suggest another reason as to why it began when it did. It goes back to Adam Smith and The Wealth of Nations. I think we haven't realised the enormous significance of developing an economy, because it empowered our 'selfish genes', over which we have no control. The challenge we face today is to think of that and to try and make our ecology dominant to the economy, and not the other way round. So that needs a political rethink.
If I could just end with a practical example that Tim Costello told me about the other day: World Vision has just done a survey in Papua New Guinea of 'greatness'. How was a man in a Papua New Guinea village perceived for his greatness as a leader? And your greatness was dependent on how much money you left when you died: you were a great man if you died broke.
Will Steffen: That looks good for my legacy, I think! Thanks very much for those comments. I think that is exactly the sort of rethinking we need to do, and I think you touched on those foundational issues that I was referring to. It is a very good comment, thank you.
Question: I can't resist saying that I heard of an Aboriginal culture where to manifest any indication that you wanted to be a leader was a crime punishable by death. I don't know if that is true, but it could be a salutary lesson – in this town!
Will, you mentioned that IPCC or some people have questioned the survival of industrial civilisation at temperature increases of 5° or 6° or something like that. I worry that it is much more fragile than that, and I mention only two things. One example is very long oil supply lines coming from politically very unstable places. The second example is the global financial system, which is threatening to collapse with no input from anything else in the world, just all by itself.
Will Steffen: Those are very good comments, and like a lot of other aspects of global change, we might underestimate this as well. But this is even trickier, I think, to anticipate and predict than the climate system, and that's pretty hard. But that is a good comment.
Michael Dopita: Let's thank Will once more.
