Science increasingly shows that the Holocene is our desired state; the state that is stable and able to support human development in a world soon to become 9 billion people. Now the drama is that the evidence on the human pressures on the planet point at the risk of us moving out of the Holocene.
And in fact it’s gone so far that science today indicates that we are entering a whole new geological epoch, the Anthropocene. Anthros for us humans, 7 billion people multiplied by our industrial metabolism today constitute a force of change, which is in pace and magnitude larger than the geological forces of change that has been pushing the planet in and out of ice ages over the geological history of Earth.
This is indeed a tremendous change in the way we are managing and taking responsibility for our Earth system. And the large changes are increasingly so well documented, not only in terms of the scientific data but also in terms of what we see around ourselves, in terms of deforestation, overfishing, overwhelming use of unsustainable fossil energy sources, and the expansion of many times unsustainable urban developments. So this is the notion and the recognition that our pressure is translating into an entirely new geological epoch.
The definition of the Anthropocene is important. It is actually not a small thing to change all the books and the definitions we have learned in school in terms of the geological epoch we’re in.
In fact it’s so significant that the institution that defines which geological epoch we’re in, of course the United Kingdom’s, Great Britain’s, Royal Society has put up a whole committee which is currently working on exploring whether we have evidence enough to redefine our epoch to the Anthropocene as a new geological era of man and the dominant force of change on Earth.
I think it’s important to recognize that in the Anthropocene we must simply relate to the new challenge of navigating what I’ve called a 3-6-9 world. On average science points in the Anthropocene that we’re moving towards a 3 degrees Celsius warming in this century. Again, this is a place we haven’t been over the past 3 million years. We are in the sixth mass extinction of species, the first mass extinction to be caused by human beings, another species in the world. One of these six, by the way, is when we lost the great, large dinosaurs some 65 million years back. And we are committed to 9 billion people.
And that this 3-6-9 world is the world of Anthropocene, which we now need to navigate in terms of finding sustainable development. It’s a world where we cannot exclude rising risks of abrupt, sudden extreme events. Science clearly shows today that already at 1 degree Celsius warming, and the environmental changes we see today in ecosystems we see a larger frequency and impact in terms of heat waves; in terms of influence and effects on rainfall patterns; and in terms of abrupt extreme events, such as the impacts of hurricanes, such as the impacts of sudden extreme weather events, related both to flooding and to droughts.
It’s a reality where global changes in Anthropocene affect local conditions, and we can no longer separate what happens locally from the global change. And therefore we need to interact across all levels in societies in order to be able to provide prosperity.
It sounds challenging to think of economic development in a large urban area having today to relate to the complex changes in the Earth system, but that is the reality. We can not develop a city, a household, an agricultural system today, planning for fresh water, clean air, ecosystem support, without also understanding that we’re changing the planetary system because it hits back on that local scale, across different scales in the world.
Now another insight of the Anthropocene is the recognition that the Earth system has stayed within very narrow bands for many of the environmental processes that we discussed, as key for sustainable development.
This is one graph showing that over the past 400,000 years, for methane and carbon dioxide, we stay within a very narrow band of just +/- a few hundred ppm on carbon dioxide, in fact never exceeding 280 ppm carbon dioxide over the entire last 500,000 years, and similarly for methane. And we just look, for example, on the situation where we are today, we are seeing that we are vastly moving out of the graph of the maximum/minimum carbon dioxide fluctuations over the past half million years.
So we’re truly in the Anthropocene performing an experiment, which is way outside of the stability domain we’ve had on the planet for the last several million years, and that these limit cycles are really important because the Earth system tries itself to apply its biogeochemical processes to stay within very narrow bounds for carbon, nitrogen, phosphorus, fresh water, temperature, and that this is a key insight in terms of also our world development.
We also must, as we increasingly recognize, connect these very, very narrow bands of limits within which the Earth system has evolved, the pressures that we’re putting on the system, to the risk of abrupt changes.
And this is one example of a very seminal piece of work led by colleagues by the Potsdam Institute of Climate Impact Research showing what are the big systems that could actually tip over a tipping point and abruptly change the conditions for life on Earth. For example, that would destabilize the Southeast Asian monsoon systems; for example, that the western Arctic ice sheet abruptly and irreversibly melts, holding several meters sea level rise; for example, that we shift the entire Atlantic thermohaline circulation system, which would make many parts of the northern temperate zones uninhabitable; or that we knock over the Amazon rainforest to a point where it turns into a savannah. These are the challenges we now must incorporate in our development paradigm.
It links also to health. If we start moving along the worst scenario on climate change, which is the red curve shown here that takes us towards 4 degrees C, we must then also recognize that infectious diseases, crop pests and diseases, heat waves and droughts, food insecurity, will increase in the world as temperatures rise, and also reach completely new geographical regions which never had these kind of impacts previously.
And now we have projections that would take us 2, 3, 4, 5, potentially 6 degrees C degrees outside of that range. This is a situation where we now must address how can we bend development back towards Holocene-like conditions, even though we are in the Anthropocene? And that we want to avoid a situation where we let unsustainable development go unbounded, which could take us to a transition into a completely new stable hot state of the planet which would not support the modern world as we know it.
So to conclude, the challenge for humanity is to recognize that the Holocene is our desired state, we’re moving into the Anthropocene, placing us in the driving seat, but we still have a choice. We can navigate ourselves away from the largest risks that the Anthropocene pose. Is this increasingly understood? I would argue yes. And the last slide here shows examples of media outside of science welcoming humanity to the Anthropocene. And The Economist has this wonderful citation in its issue welcoming humanity to the Anthropocene, which I think is a good reflection of how science feels today in the face of these global risks. And it says exactly as follows, “That when reality is changing faster than theory suggests it should a certain degree of nervousness is a reasonable response.”
And I think that is one of the guiding principles for sustainable development in the Anthropocene that precaution must be operationalized as a guiding principle for human development.