Coût d’opportunité versus coût du maintien des potentialités écologiques : deux indicateurs économiques pour mesurer les coûts de l’érosion de la biodiversité

The cost of ecosystem services degradation is a major topic as underlined by the TEEB program (The Economics of Ecosystems and Biodiversity), which proposed an assessment of the costs of policy inaction in the field of biodiversity conservation. In the same vein, the report of the French Centre for Strategic Analysis on the Economic Approach to Biodiversity and Ecosystem Services turns its attention to the value of ecosystem services, suggesting some elements that could help measure the cost of biodiversity degradation. There is however some confusion regarding the notion of cost. Thus, in the case of TEEB the proposed cost assessment translates into monetary terms the loss of potential profits from ecological services. Yet, another way of assessing these costs could be to estimate the investment required to maintain the ecological potential of ecosystems to deliver these services. This latter approach may be considered better suited to the concept of “inaction” proposed by the TEEB report. In addressing this point, the paper attempts to identify the operational implications of these two assessment methods and their links with decision-making. One of our findings is that the economic approach to biodiversity tends to focus systematically on the question of the monetary value of ecosystem services while regulatory texts increasingly consider the cost assessment of maintaining ecosystem services.