Costanza’s Number: Ordering and Valuing our Relations with Nature

Helen Verran, University of Melbourne

I tell a story of a number 'born' in 1997 in the prestigious natural sciences journal Nature in a paper entitled “The value of the world's ecosystem services and natural capital”.  Lead author Robert Costanza and twelve others presented data that they claimed allowed calculation of a numerical value for the goods and services produced by the world’s natural capital stock.  The paper can be understood as a spectacular intervention in the politics around the move to market-led environmental policy. I use Costanza’s number as an exemplar of the modern habit of eliding ordering and valuing in using numbers.

I argue that Costanza’s number fails to recognize and respect the difference between number’s working as ordinal number to conserve order and as cardinal number to conserve value. The number’s presentation in the Nature paper hides a conflation of the deductive working of number’s generalizing where parts are derived from general, vague wholes in processes effecting ordering—the form of number use familiar in economics, with the inductive form of number’s generalizing associated with valuing by engaging a specific one-to-many relation—the ways numbers are engaged with by most natural scientists.

Does it matter that a much-cited number elides valuing and ordering?  My claim is that the conflating is not the problem—if we know what we’re doing, flipping between ordering and valuing can be generative.  The danger lies in the fact that many who love numbers use them constantly cannot recognize the difference between these two moments of numbering and hence are unable to discern when conflation is occurring.  That we don’t know we are conflating number’s dual moments of generalising is a problem.

As contemporary ecological economics tells it, either directly or indirectly in the functioning of ecosystems nature produces goods (like food, fibres, water, and minerals) and services (like waste assimilation, nutrient cycling and the means to perform culturally significant rituals like bush-walking).  These goods and services provide benefit to human societies.

Thirteen authors representing a wide range of academic institutions and disciplines, presented data that they claimed allowed calculation of a numerical value for the goods and services produced by the world’s natural capital stock. As they calculated it, the numerical value of the goods and services provided annually by the environment was somewhere between US$16 and 54 trillion (1012) which they averaged as US$33 trillion (1012) per year.  They compared their newly hatched number to another number: the total of the global gross national product that they estimated at US$18 trillion (1012) per year.