Johan Rockström: Protecting the Earth’s systems from catastrophic failure

The basic reason is that major advances in Earth system science now show that humanity is facing the risk of large-scale, potentially catastrophic tipping points that could hamper human development. The evidence shows that we may have entered a whole new geological epoch, the Anthropocene, where humans constitute the main geological force changing planet Earth. The planetary boundaries framework was developed to address this new reality.

But the insight of the Anthropocene gives you only the very first step, because it just indicates we have a high degree of human pressure. The second is the risk of nonlinear change, which comes out of resilience theory and from empirical evidence that particular ecosystems have multiple stable states. We see evidence that lakes and forests and wetlands can have different equilibria — so you have a savanna system that may be stable and thriving, but it can also tip over and become an arid steppe if pushed too far by warming, land degradation and biodiversity loss. A clear-water lake can become a murky, biodiversity-low anoxic lake. Unfortunately, the science is increasingly showing that even large systems can tip. There’s paleoclimatic evidence that if oceans get an overload of phosphorus, they could collapse with large dead zones. The largest ice sheets also show evidence of shifts between ice-covered and ice-free states.

We asked ourselves: OK, so if we are in the Anthropocene, and if we are at risk or have evidence of large regional to global tipping points, then what is our desired state for planet Earth? What is the state at which Earth needs to be in order to support human well-being in a world of 7 — soon to be 9 — billion people?

Paleoclimatic records show clearly that the past 10,000 years, the Holocene, is a remarkably stable period in which we went from being a few hunters and gatherers to become more sedentary agriculture-based civilizations, which then moved us to the current populated modern era. So there’s robust evidence that the Holocene is our desired state and the only state we know that can support the modern economy. If we know that, we can also define the biophysical preconditions: What are the Earth system processes that determine the Holocene’s familiarity? Can we for those processes identify tipping points we want to avoid? The insight of the importance of the Holocene stability provides humanity with a science-based analysis of global sustainability goals that should be met to provide us safe operating space for human development.

There are so many challenges and steps that need to be taken. But if one thinks of it as entering a funnel, I think a broad entry point is the need for a shift in mind-set. It might sound a bit awkward — the first thing one thinks of is probably new economic paradigms, really hard new governance structures, new policies. All of that is of course required, but the precondition is that modern society reconnect to the biosphere, which in turn requires a mind shift. Today we operate the world with our growth paradigm and our economic imperative and our social imperative as being the supreme goals for our societies. We then add, at best, sustainable development, corporate social responsibility and all the good work we’re doing with clean tech and efforts to be more efficient, all with the explicit goal of minimizing environmental impacts within the overarching growth paradigm. The insights of the Anthropocene and tipping points show this paradigm doesn’t work anymore. We have to reverse the whole order and agree that the biosphere is the basis for everything else. This is quite dramatic, because it means human development has to be subordinate to Earth system boundaries. It changes the whole idea of macroeconomic theory, because macroeconomic theory basically states that as long as you put the right price on the environment, you automatically get the most cost-efficient way of solving environmental problems.

The second dimension is the idea of planetary stewardship, which means taking ourselves from 196 nation-states operating in their own interest as individual entities to joint governance at the planetary scale. We need to strengthen global governance. We need a global agency that governs, monitors, verifies and reports on whether we’re on aggregate meeting planetary boundaries. That is something a world environment organization could do. This is not to say bottom-up initiatives are not important. On the contrary, they are a precondition for success. But in the Anthropocene, where we need to urgently bend the global curves of negative environmental change, we need to provide leadership also at the global scale. This is lacking today.

There is more and more scientific evidence that suggests it is very urgent. For climate, biodiversity and nitrogen, we are already in the slippery danger zone where we cannot exclude tipping over thresholds. On climate, we’re seeing evidence of a destabilization of the Arctic ice sheet. On nitrogen, we’re seeing clear evidence of major tipping points where lakes are losing their capacity to support human well-being due to overuse of nitrogen and phosphorus particularly in modern agriculture. On biodiversity, we’ve reached the point where humanity is causing an extinction of species equivalent to losing the dinosaurs 65 million years ago — at the same time we’re also learning how much we depend on biodiversity. We have increasing evidence we need to back off also on phosphorus and that we’re approaching dangerous boundaries for freshwater and for land. So we have a decade right now that is very decisive.

And the reason it’s urgent is not that we risk catastrophic outcomes in one year or five years or 10 years. It is because what we do today injects changes in Earth systems that may cause thresholds in 50 years’ time, 100 years’ time. The future of coming generations is thus truly in this generation’s hands. And we have already committed ourselves to major risks of tipping points in the coming century. That’s why we need to go much, much faster on turning back into the safe operating space.

For the boundaries that we have already transgressed, we can’t exclude that this decade is a determining decade, that we need to bend the curves of negative environmental change before 2020. There’s a lot of strong evidence that’s the case.

That’s a very interesting question, because there’s very little or no science to suggest that a global transition to sustainability, a global transition to a future within planetary boundaries, would be a worse world than the world we know today. On the contrary, there is increasing evidence to suggest that a transition can be done while providing us with good chances of prosperity even on a crowded planet.

But there is a big “but”: And the big but is, have we already gone too far? And that we simply don’t know yet.