Climate Change, Planetary Health and the Deep Significance of the Anthropocene

Written by Joseph Moore

Preventing global climate change is currently the main item on our collective environmental agenda. I am certainly convinced of the need to reduce carbon emissions, restore carbon-sequestering ecosystems, generate renewable energy and develop more sustainable economic practices. Yet as I reflect on the nature of life and the history of the planet, it seems to me that mitigating or hopefully even undoing anthropogenic climate change is but a first step, an emergency measure in an environmental triage. If we do manage to stabilise the global climate, we will then face questions and issues of even longer-term environmental ethics and policy. Specifically, we will know how to push the global climate in any direction, towards higher or lower average temperatures and levels of atmospheric carbon, and with that knowledge and ability comes responsibility. Deciding how best to use this knowledge will require deciding how we want to relate to other forms of life, to the planet and to its ecosystems—or so I will suggest.

I do not have answers to these long-term questions, and they may not be as pressing as more immediate practical concerns, but here I want to begin to put some of these issues forward for discussion. We will (hopefully!) have to reckon with them eventually and being aware of them now might impact how we go about trying to prevent climate change in the present.

My reflections stem from the fact that the Earth’s climate changes without the influence of humans. Average global temperatures have been much lower and much, much higher than they are today (Fig. 1). And for at least 3.7 billion years of the Earth’s 4.5 billion-year history, life has found a way to change with it. The same environmental factors that most concern us today have been implicated in mass extinction events and adaptive radiation of new species: temperature, sea levels, oxygen, ozone, sulfur oxides, carbon dioxide. Global warming after large volcanic eruptions may have caused the dinosaurs to become ascendant; impact winter and the acidification of oceans and rainwater after the asteroid hit probably wiped them out and made room for mammals to diversify.

Some have cited these natural fluctuations to make the case that the current bout of rising global temperatures is not the result of human action and therefore not something we need to solve by changing our behaviour. This is not my point at all—quite the contrary. It is not an inexplicable coincidence that the millennia-long trend of gradual global cooling sharply reversed following the invention of the steam engine (Fig. 2). Human industrialisation appears to be having the global effect of massive volcanic eruptions without the volcanoes.

What I am grappling with now is precisely that, as far as we can tell, humans are driving climate change, we know how we are doing so and, moreover, it seems well within our collective knowledge and power to push the global climate in either direction. Right now, the name of the game is reducing our carbon emissions as much as possible to minimize anthropogenic climate change, which is likely to be extremely harmful to many ecosystems, species and individuals, including many people, especially the worst-off. To undo existing damage and to avoid the extreme weather that we’ve been experiencing of late, it would be even better to return atmospheric carbon to pre-industrial levels by restoring and expanding carbon-sequestering ecosystems, like forests and wetlands, or capturing and storing carbon by artificial means.

But suppose we did successfully undo anthropogenic climate change and returned the Earth to its pre-industrial cooling trajectory. And then suppose that inevitable natural forces began pushing the planet towards another ice age or towards another hot period, as in the Cretaceous period. Humans would then face a collective choice of whether to let nature take its course or to intervene in order to prevent or mitigate natural global climate change. We could resume our carbon-emitting industrial practices to avoid global cooling, or we could re-double our carbon-sequestering efforts to avoid global warming. But even letting nature take its course would involve a conscious choice on our part, since we would know that we could intervene, assuming the climatic event was not so cataclysmic as to wipe out our scientific knowledge or technological capacities altogether.

This is the deeper significance of the proposed classification of the current geological era as the Anthropocene: not just that humans are impacting the global environment but that we know how to do so. As long as our current knowledge and capacities remain the same or, more likely, expand, humans will effectively be in the position of ‘signing off on’ the global climate and its direction. Like it or not, we are in an era of planetary engineering. And those of us who share in this collective know-how are also collectively responsible for the effects of human action or inaction, effects on humans as well as on the rest of the natural world.

Many ethical questions, concerns and complexities are sure to arise with this collective ecological responsibility. I do not know what the morally or prudentially best course of global environmental action will be in the distant future. I do think it wise at present to curb carbon emissions and even to attempt to restore atmospheric carbon to pre-industrial levels since the risks of anthropogenic climate change are enormous and our climatic scientific knowledge, while impressive, is still in relative infancy. When the stakes are high and your information is poor, it makes sense to buy time to learn more and to prepare practically for various possible outcomes. But quite possibly, whether and how humans should intervene in the global environment, even to undo our past effects, will change over time as natural and technological circumstances change.

Rather than advocate a specific long-term policy, my main purpose here has been to draw our attention to the need to think carefully and critically, now and in the future, about the ethics of our environmental impacts and efforts, even our well-meaning ones. We cannot rest content merely to reach net zero carbon emissions—as difficult as that will be—and then bury our heads in the sand while the planet inevitably continues to change around us. Of course, we should also not view ourselves as beneficent custodians of the natural world either, any more than as passive bystanders. We do not stand apart from or over the natural world; we are one group of influential, active participants and beneficiaries among many others. But having become aware of our influence, we must henceforth exercise it thoughtfully.

I’ll conclude with what I take to be at least one small contribution to the necessary ethical discussion. The concept of ‘planetary health’ is often invoked nowadays as an architectonic goal of climate action and environmentalism. It sounds like a no-brainer: health is better than ill health. But I fear that ‘planetary health’ is being used to refer not to the health of the planet or of the global environment, but merely to human health and conditions that are known to be acceptably good for humans. Indeed, the agenda-setting Rockefeller-Lancet Commission on planetary health summarises its definition as ‘the health of human civilisation and the state of the natural systems on which it depends’.[1] ‘Planetary health’ is at best a very misleading term for human health.

This use of the term suggests the kind of status quo bias and human-centred short-sightedness that we should guard against going forward. Indeed, it seems like the current climate crisis is, in part, the result of people evaluating the natural world solely on the basis of its ability to support familiar human ways of life. Whether we are interested in other species and ecosystems for their own sakes or only insofar as they ultimately serve human interests, we must try to broaden our perspectives beyond merely the human, the present and the recent past. We should bear in mind that a ‘healthy’ planet and the life it supports might naturally change over time, just as a healthy deciduous tree sheds and re-grows its leaves and a healthy human permanently sheds its baby teeth. Given that life never stops evolving, it is very unlikely that we could entirely freeze the planet at one point in time and it’s not clear that we should want to do so anyway. There may be benefits as well as dangers in the various ecological possibilities beyond our snapshot of Earth’s geological history. Since life and the planet are always changing, perhaps in the long run—after we clean up our collective messes—we would do best to prepare ourselves to change along with them.

[1] Sarah Whitmee, et al. ‘Safeguarding human health in the Anthropocene epoch: report of The Rockefeller Foundation-Lancet Commission on planetary health’, The Lancet 386, no. 10007 (14 November 2015): 1973-2028. https://doi.org/10.1016/S0140-6736(15)60901-1.