Johan Rockstrom: Let the environment guide our development

Johan Rockstrom: Let the environment guide our development

2015-12-01    18'26''

主播: Contender

3170 521

介绍:
As the 21st session of the Conference of the Parties(COP 21) with more than 190 nations gathering in Paris to discuss a possible new global agreement on climate change, let us focus on environment talks from TED. +++++++ Transcript: We live on a human-dominated planet, putting unprecedented pressure on the systems on Earth. This is bad news, but perhaps surprising to you, it's also part of the good news. We're the first generation -- thanks to science -- to be informed that we may be undermining the stability and the ability of planet Earth to support human development as we know it. It's also good news, because the planetary risks we're facing are so large, that business as usual is not an option. In fact, we're in a phase where transformative change is necessary, which opens the window for innovation, for new ideas and new paradigms. This is a scientific journey on the challenges facing humanity in the global phase of sustainability. On this journey, I'd like to bring, apart from yourselves, a good friend, a stakeholder, who's always absent when we deal with the negotiations on environmental issues, a stakeholder who refuses to compromise -- planet Earth. So I thought I'd bring her with me today on stage, to have her as a witness of a remarkable journey, which humbly reminds us of the period of grace we've had over the past 10,000 years. This is the living conditions on the planet over the last 100,000 years. It's a very important period -- it's roughly half the period when we've been fully modern humans on the planet. We've had the same, roughly, abilities that developed civilizations as we know it. This is the environmental conditions on the planet. Here, used as a proxy, temperature variability. It was a jumpy ride. 80,000 years back in a crisis, we leave Africa, we colonize Australia in another crisis, 60,000 years back, we leave Asia for Europe in another crisis, 40,000 years back, and then we enter the remarkably stable Holocene phase, the only period in the whole history of the planet, that we know of, that can support human development. A thousand years into this period, we abandon our hunting and gathering patterns. We go from a couple of million people to the seven billion people we are today. The Mesopotamian culture: we invent agriculture, we domesticate animals and plants. You have the Roman, the Greek and the story as you know it. The only phase, as we know it that can support humanity. The trouble is we're putting a quadruple sqeeze on this poor planet, a quadruple sqeeze, which, as its first squeeze, has population growth of course. Now, this is not only about numbers; this is not only about the fact that we're seven billion people committed to nine billion people, it's an equity issue as well. The majority of the environmental impacts on the planet have been caused by the rich minority, the 20 percent that jumped onto the industrial bandwagon in the mid-18th century. The majority of the planet, aspiring for development, having the right for development, are in large aspiring for an unsustainable lifestyle, a momentous pressure. The second pressure on the planet is, of course the climate agenda -- the big issue -- where the policy interpretation of science is that it would be enough to stabilize greenhouse gases at 450 ppm to avoid average temperatures exceeding two degrees, to avoid the risk that we may be destabilizing the West Antarctic Ice Sheet, holding six meters -- level rising, the risk of destabilizing the Greenland Ice Sheet, holding another seven meters -- sea level rising. Now, you would have wished the climate pressure to hit a strong planet, a resilient planet, but unfortunately, the third pressure is the ecosystem decline. Never have we seen, in the past 50 years, such a sharp decline of ecosystem functions and services on the planet, one of them being the ability to regulate climate on the long term, in our forests, land and biodiversity. The forth pressure is surprise, the notion and the evidence that we need to abandon our old paradigm, that ecosystems behave linearly, predictably, controllably in our -- so to say -- linear systems, and that in fact, surprise is universal, as systems tip over very rapidly, abruptly and often irreversibly. This, dear friends, poses a human pressure on the planet of momentous scale. We may, in fact, have entered a new geological era -- the Anthropocene, where humans are the predominant driver of change at a planetary level. Now, as a scientist, what's the evidence for this? Well, the evidence is, unfortunately, ample. It's not only carbon dioxide that has this hockey stick pattern of accelerated change. You can take virtually any parameter that matters for human well-being -- nitrous oxide, methane, deforestation, overfishing land degredation, loss of species -- they all show the same pattern over the past 200 years. Simultaneously, they branch off in the mid-50s, 10 years after the Second World War, showing very clearly that the great acceleration of the human enterprise starts in the mid-50s. You see, for the first time, an imprint on the global level. And I can tell you, you enter the disciplinary research in each of these, you find something remarkably important, the conclusion that we may have come to the point where we have to bend the curves, that we may have entered the most challenging and exciting decade in the history humanity on the planet, the decade when we have to bend the curves. Now, as if this was not enough -- to just bend the curves and understanding the accelerated pressure on the planet -- we also have to recognize the fact that systems do have multiple stable states, separated by thresholds -- illustrated here by this ball and cup diagram, where the depth of the cup is the resilience of the system. Now, the system may gradually -- under pressure of climate change, erosion, biodiversity loss -- lose the depth of the cup, the resilience, but appear to be healthy and appear to suddenly, under a threshold, be tipping over. Upff. Sorry. Changing state and literally ending up in an undesired situation, where new biophysical logic takes over, new species take over, and the system gets locked. Do we have evidence of this? Yes, coral reef systems. Biodiverse, low-nutrient, hard coral systems under multiple pressures of overfishing, unsustainable tourism, climate change. A trigger and the system tips over, loses its resilience, soft corals take over, and we get undesired systems that cannot support economic and social development. The Arctic -- a beautiful system -- a regulating biome at the planetary level, taking the knock after knock on climate change, appearing to be in a good state. No scientist could predict that in 2007, suddenly, what could be crossing a threshold. The system suddenly, very surprisingly, loses 30 to 40 percent of its summer ice cover. And the drama is, of course, that when the system does this, the logic may change. It may get locked in an undesired state, because it changes color, absorbs more energy, and the system may get stuck. In my mind, the largest red flag warning for humanity that we are in a precarious situation. As a sideline, you know that the only red flag that popped up here was a submarine from an unnamed country that planted a red flag at the bottom of the Arctic to be able to control the oil resources. Now, if we have evidence, which we now have, that wetlands, forests, [unclear] monsoon system, the rainforests, behave in this nonlinear way. 30 or so scientists around the world gathered and asked a question for the first time, "Do we have to put the planet into the the pot?" So we have to ask ourselves: are we threatening this extraordinarily stable Holocene state? Are we in fact putting ourselves in a situation where we're coming too close to thresholds that could lead to deleterious and very undesired, if now catastrophic, change for human development? You know, you don't want to stand there. In fact, you're not even allowed to stand where this gentleman is standing, at the foaming, slippery waters at the threshold. In fact, there's a fence quite upstream of this threshold, beyond which you are in a danger zone. And this is the new paradigm, which we gathered two, three years back, recognizing that our old paradigm of just analyzing and pushing and predicting parameters into the future, aiming at minimalizing environmental impacts, is of the past. Now we to ask ourselves: which are the large environmental processes that we have to be stewards of to keep ourselves safe in the Holocene? And could we even, thanks to major advancements in Earth systems science, identify the thresholds, the points where we may expect nonlinear change? And could we even define a planetary boundary, a fence, within which we then have a safe operating space for humanity? This work, which was published in "Nature," late 2009, after a number of years of analysis, led to the final proposition that we can only find nine planetary boundaries with which, under active stewardship, would allow ourselves to have a safe operating space. These include, of course, climate. It may surprise you that it's not only climate. But it shows that we are interconnected, among many systems on the planet, with the three big systems, climate change, stratospheric ozone depletion and ocean acidification being the three big systems, where the scientific evidence of large-scale thresholds in the paleo-record of the history of the planet. But we also include, what we call, the slow variables, the systems that, under the hood, regulate and buffer the capacity of the resilience of the planet -- the interference of the big nitrogen and phosphorus cycles on the planet, land use change, rate of biodiversity loss, freshwater use, functions which regulate biomass on the planet, carbon sequestration, diversity. And then we have two parameters which we were not able to quantify -- air pollution, including warming gases and air-polluting sulfates and nitrates, but also chemical pollution. Together, these form an integrated whole for guiding human development in the Anthropocene, understanding that the planet is a complex self-regulating system. In fact, most evidence indicates that these nine may behave as three Musketeers, "One for all. All for one." You degrade forests, you go beyond the boundary on land, you undermine the ability of the climate system to stay stable. The drama here is, in fact, that it may show that the climate challenge is the easy one, if you consider the whole challenge of sustainable development. More transcript please refer to: http://www.ted.com/talks/johan_rockstrom_let_the_environment_guide_our_development/transcript?language=en