(6 May)  I have a new blog post at the UEA 3S Blog [now defunct: 19-Jan-2021]: ‘Metaphors: taking responsibility for our choices’ in which I reflect on the power and hazards of crafting metaphors in environmental science.

A few weeks ago at the launch event of the York Environmental Sustainability Institute (YESI) I heard Johann Rockström, champion of the idea of planetary boundaries, give one of his whirlwind talks about the state of the planet and how he saw the challenges ahead.  In his talk he used a striking metaphor which I had not heard before: ‘the Earth System is presenting us with invoices which will have to be paid.’

I was particularly tuned-in to metaphors because in my talk the following day I was going to draw attention to the centrality of metaphor in how environmental science is framed and communicated.  So I began to make a note of some of the other metaphors Rockström used in his 45 minute talk.  Here are some of them: ‘Mother Earth’; ‘Spaceship Earth’; ‘under the hood of the Earth System’; ‘hit the ceiling of the hard-wired Earth System processes’; ‘humanity has reached the saturation point’; ‘tipping points in the Earth System’; ‘Earth System using its palette of biomes and systems’; ‘Earth System starting its engine of positive feedbacks’; ‘the planetary ceiling and the social floor’.

Metaphors are the very necessary ways we use language to represent the unfamiliar in terms of the familiar.  This is as true for scientists as for anyone else.  But metaphors are of course only suggestive.  They are figurative, not literal.  Metaphors abandon the pretence that we can describe things as ‘they truly are’ from a God’s-eye point of view.  Rather, they concede that we can only see the world around us and inside us from a human-eye view.  Consequently, metaphors are never innocent.  They are ‘performative’; they powerfully influence our interpretations of reality.  As metaphors circulate around our cultural worlds they exercise huge influence on how we imagine reality to be structured and they condition how we might respond to that imagined reality.

This is as true of our understanding of the planet as it is of our own bodies.  Is the Earth a spaceship to be steered (by us?) on a journey, an Earth mother with whom we must bond or, as in the case of planetary boundaries, a dashboard with dials to be managed so that the indicators are kept out of the red zone?  Rockström used all three of these metaphors in his talk, presumably as a means of communicating his ideas in an engaging way.

But we need to choose our metaphors carefully, as Brendon Larsen has beautifully shown in his book Metaphors for Environmental Sustainability: Re-defining our Relationship with Nature.  Larson shows, for example, how the metaphor of bar-coding for representing the identification of species according to their DNA, contributes to a commodification of human relationships with animals.  And how the metaphor of the selfish gene changes the way we think about human self-image and ethical behaviour.  Metaphors cannot be discovered, only chosen.  And we need to be careful with our choices – and take responsibility for the consequences.

The introduction of the metaphor of tipping points into climate science is a good example of this.  First used in a climate science paper in 2005, the tipping point metaphor has re-shaped not just how climate change is communicated – by politicians, campaigners, journalists and artists – but it has re-defined some of the objectives and funding priorities of climate science.  There are funded research programmes dedicated to understanding tipping points in the Earth System.  There are new methods being developed to try and offer early warnings of climate tipping points.

One can argue of course that these are highly creative and potentially fruitful lines of scientific inquiry – but we should not mistake metaphor for reality.  Richard Dawkins’ choice of metaphor in 1976 for the human gene – as selfish – has had profound consequences for many areas of intellectual thought and public discourse (as Larsen again shows).  We need to think carefully about our choice of metaphor and sometimes be willing to change them.