Value of the world’s ecosystem services: the influence of a single paper
In 1997, myself and 12 colleagues published a paper in Nature that estimated the value of the world’s ecosystem services. The paper was a global synthesis of information about how important natural ecosystems are to supporting human welfare. It was unique in that it not only asserted that ecosystems are important, but quantified how important they are in units (dollars) that were easy to compare with other things that support human welfare. The paper acknowledged the many difficulties, limitations, and controversies surrounding such an exercise, but concluded that solving these problems would lead to even larger values. It also came up with a range of values — $16 – $54 Trillion/yr (with a mean of $33 Trillion/year in $1994)—as the estimated total annual non-marketed contribution of ecosystems to human welfare. Since this number was significantly larger than global GNP and was obviously still an underestimate, it led to the inescapable conclusion that ecosystems are much more important to human welfare than had been previously assumed by many, and that they therefore deserved much more attention. A main goal of the paper was to encourage further discussion and research. Since its publication, the paper has been cited in the scientific literature almost 1000 times (as of Oct 2006), making it the second most highly cited article in the ecology/environment field in the last decade. This high citation rate indicates that the paper achieved its goal of encouraging further discussion and research.
The paper has influenced several fields in slightly different ways. The environment/ecology field has embraced the concept of ecosystem services as a way to effectively make the link between ecosystem functioning and human welfare. The Millennium Ecosystem Assessment is just one of several initiatives that have been organized around the concept of ecosystem services. This field has also been more open to alternative methods of valuation of ecosystem services, but there are a significant subset of people that are skeptical of any attempt to value ecosystem services. This is partly due to the misconception that valuing non-marketed ecosystem services (which are mainly public goods – non-rival and non-excludable) is the same a privatetizing and commodifying them as if they were private goods. This is simply not the case.
Some professional economists have been less positive, largely for the wrong reasons. They have argued with the paper’s methods, but, as noted above, these objections were duly noted in the paper itself, and only make the results more conservative. I think the deeper (unstated) objection is that they feel that if ecosystems are really as important as the paper shows, then what they have been studying all these years is less important.
The field of ecological economics has been guardedly supportive, wishing to both acknowledge the importance of ecosystems and to emphasize the limitations of the study’s methods. In all cases, however, the paper has stimulated significant discussion of these issues and that has been a positive factor.
Since the publication of this paper, there has been an explosion of research on the value of ecosystem services. A random sample includes: (1) a follow-up working group at NCEAS produced a special issue of Ecological Economics delving into many of the questions that the original paper raised; (2) the National Science Foundation now lists ecosystem services and their valuation as a core item on the environmental research agenda; (3) the ISI Web of Science now lists over 500 papers when one enters the term "ecosystem services" in the topic search field; (4) a growing number of research projects and policy initiatives are being undertaken using ecosystem services as a core organizing principle.
In the next 10 years I expect the concepts of ecosystem services and natural capital to become core concepts in how we think about and manage humanity’s relationship with the rest of nature.
- Costanza, R., R. d'Arge, R. de Groot, S. Farber, M. Grasso, B. Hannon, S. Naeem, K. Limburg, J. Paruelo, R.V. O'Neill, R. Raskin, P. Sutton, and M. van den Belt. 1997. The value of the world's ecosystem services and natural capital. Nature, 387:253-260.
- Costanza, R. and S. Farber (eds.) 2002. The Dynamics and Value of Ecosystem Services: Integrating Economic and Ecological Perspectives. Special Issue of Ecological Economics, 41:367-560.