Among the media coverage of last week’s COP26 meeting in Glasgow one particular analogy stood out to me.  It claimed that the Glasgow Climate Pact was a failure by analogy of having a 2 metre chasm to jump across to safety, but one’s personal best in the long-jump being only 1.9m.  The leap might be only 0.1m short, but it was the difference between safety and death.  In similar mode, much reporting from COP26 talks about “the last-best chance to stop dangerous climate change” or that the chances of limiting warming to 1.5°C were now “hanging by a thread”.

These absolutist framings of the challenges presented by a changing climate, and the metaphors of success or failure, lean heavily on the numbers which in recent years have come to guide the science, politics and ethics of climate change. 

I have commented extensively in the past about the dangers of such numerical reductionism.  It may make for bold and arresting reporting, but it is neither helpful, nor accurate, for communicating the nature of the challenge.

For example, take the headline numbers enshrined in the Paris Agreement: limiting warming to 2°C and “pursuing efforts” to limit it to 1.5°C.  At best, such numbers are vague approximations to some of the dangers of climate change, but they can also be used to mis-represent the nature of the scientific knowledge upon which these political numbers are claimed to rest.

This is because the relationship between a given future volume of emitted carbon and the eventual global temperature is known only probabilistically.  So when the high profile non-profit organisation Climate Action Tracker says that the pledges made at Glasgow equate to 2.4°C they are referring to the estimated warming which would occur with a 50% likelihood. 

It is easy to see that this knowledge could be expressed differently.  The existing pre-Glasgow pledges could be said to have offered only, say, a 15% likelihood of limiting warming to 2°C, but the outcome of the Glasgow Climate Pact has shifted this likelihood to, say, a 30%.  (The numbers I use here are illustrative; but my point does not depend on the specific numbers and the same principle would apply if the likelihood of 1.5°C were to be used, although the likelihoods would of course be lower). 

The dial has shifted towards an increased chance of limiting warming to 2°C (or 1.5°C).  This framing also opens the prospect of future government pledges, or other technological developments, further shifting the dial towards increased likelihood.  Such communication frames differently the relationship between scientific knowledge, emissions trajectories and the Nationally Determined Contributions issued by governments.  It replaces the unhelpful binary imagery of chasms which we fail to jump across or cliff edges which we fall over.  It undermines the narrative of “It’s too late”.

This framing of likelihoods is more faithful in representing the uncertainties of the future, whether this be how far governments will honour their pledges, how other factors affecting emissions will unfold – for example cultural and technological changes – and indeed the incomplete knowledge we have of how exactly the climate system will unfold.  We therefore need analogies and metaphors that better reflect this reality than the misguided ones being thrown around at present.

So let me suggest one. 

I have in my mind a picture in which “we”–a caravan of camels each representing a nation of the world—are walking along a valley.  There is an enveloping toxic fog, being blown along the valley behind us.  We don’t know the wind speed, nor the micro-dynamics of the gaseous cloud, but we know our task is to keep moving along the valley at a speed which exceeds that of the poison cloud.

We also do not fully know the precise path to follow out of the valley.  We are pretty sure there are swamps, rivers and other obstacles to surmount along the way.  We send out scouts ahead of the caravan to sense where particular dangers might lie and to help us avoid those most clearly identifiable.  The valley has no ending.  There is no absolutely safe place to reach – all we know is that we must keep moving.  We are on a journey along the valley, but we do not know where it will take us.

And let me add a further twist to my picture.  The caravan can only move at the pace of the slowest and towards the very back of the caravan is a large bulky camel called “India”.  It is moving much more slowly than most of the others.  It is large, but a huge burden is fastened to its back called “poverty”.  There is much shouting and cajoling from the front of the caravan urging this laggard to hurry up.

Is it wrong for the camels further ahead in the caravan to berate the Indian camel for not moving more quickly?  Or rather should these camels offer to lighten the camel’s burden of poverty and thus speed up the overall pace of the caravan?

All analogies are flawed, but I am convinced that this analogy better reflects the status of our scientific knowledge (we don’t know quite how fast the poison cloud is following us), the unknown possibilities of the human development path (the swamps and so on) and the difficult geopolitics of the world we inhabit (the scapegoating of the Indian camel).

In my picture, rather than confirming that we will fall into a chasm, the Glasgow Climate Pact has in fact confirmed that we are moving just that little bit faster than before.  And that is a good thing.

Mike Hulme, 15 November 2021, Cambridge