Warning tape and turning points: how we talk about planetary boundaries


Last week, updated research on ‘planetary boundaries’ was published, with new analysis of what humanity is doing to various natural processes and the risks we face as a species.

Reading the paper, I was struck by the prominence, alongside the various statistics and methodology, of something quite different: the authors spend some effort to define what boundaries are (and are not), their origins, why they are called boundaries, and how they might inform people’s responses to environmental threats.

What’s striking about the word ‘boundary’ is how much work it does.

The authors start with a brief historical note:

“early industrial societies often used local waterways and airsheds as dumping grounds for their waste and effluent from industrial processes. This eroded local and regional environmental quality and stability, threatening to undermine the progress made through industrialization by damaging human health and degrading ecosystems. Eventually this led to the introduction of local or regional boundaries or constraints on what could be emitted to and extracted from the environment…”

The modern use of ‘planetary boundaries’ has important variations on this practice. The authors identify Earth systems thinking, and indeed thinking of anything as ‘planetary’, as relatively recent developments. In contrast, boundaries (linked to constraints about resources & pollution) are rooted in history – they’re just being applied here in a slightly different way. But how?

A planetary boundary is global and defined by experts rather than by local landowners or authorities. It’s not the same as a ‘threshold’ – nothing dramatic will immediately happen when it is reached. Rather, it is designed to act as a sort of pre-threshold to provoke action to stop pollution or environmental degradation going too far. It allows space to turn round.

This all takes some getting used to. New terms are like people you meet at a wedding. You want to make a connection with them. You’re delighted if you find a common friend. It might remind you of a story about them, or shed new light on a familiar personality trait.

So it is when we are introduced to ‘planetary boundaries’. As we discover its technical definition in relation to terms like ‘thresholds’, a ‘safe operating space’, ‘limits’ and ‘turning points’, the picture becomes clearer and a set of associations are built up.

We can’t help linking it to what we already know. Using a physical, visual metaphor helps us to make these connections.

A Washington Post article by Joel Achenbach includes a set of vivid analogies from an Earth systems expert, Ray Pierrehumbert: planetary boundaries are “not like the edge of the cliff”, but like “avalanche warning tape on a ski slope”, or “like high-temperature gauges on your car”. Achenbach himself says they are a kind of report card.

Elsewhere in the article, Katherine Richardson (one of the new paper’s authors) reflects on the links between boundaries and limits and how that might play with an American audience: ”If you think about it, the American ethic is, The sky’s the limit. And here you have people coming on and saying, no it isn’t, the Earth’s the limit.” This neatly sums up the kind of political problems that environmentalists might have in selling these ideas to mainstream culture in the USA (and indeed many other countries).

For the idea of planetary boundaries in particular, these associations are not accidental, nor a fluffy add-on to the statistics or the systems analysis – they are all intrinsic parts of a whole. They will shape any policy responses, and may even influence decisions on scientific funding, steering the shape of research into the future. They also have a kind of moral effect as we might decide to take certain steps not to ‘transgress’ them – a word that, whether intentionally or not, has legal and spiritual connotations. (Who the word ‘we’ refers to in that sentence, and how decisions are made, are also important.)

For all the calculations about biodiversity loss and carbon dioxide levels, a crucial task of the paper is to fix this complex of ideas in our mind, helped by the colourful diagrams with concentric circles that are featured in most media coverage. In the mind’s eye these boundaries might take on a physical form. The concentric circles happen to be round, but they also look like the Earth viewed from space. Since the Earth was first photographed from space in the 1950s, that view has become entangled with ideas about environmental protection and responsibility.

What action will be taken in response may be informed by the technical data. But it will also be shaped by people’s views about how far they want to go towards the edge of the cliff – framed by a compelling metaphor that will challenge many people to think differently about their relationship to the environment.


Related posts:

’Thousands of models’: planetary boundaries, politics and power by Adrian Smith

Photo: London Zoo – Do not cross the safety barrier – sign by Elliott Brown on Flickr (cc-by-2.0)