Évaluation économique des écosystèmes marins et côtiers
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VALUE OF MARINE AND COASTAL ECOSYSTEM SERVICES
Total Value of Martinique's Marine and Coastal…
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Public and economic policies have long considered nature as res nullius, something that has no owner. Ecosystem services

Ecosystem services are defined as those functions of ecosystems that (directly or indirectly) support human welfare. They occur at multiple scales, from climate regulation and carbon sequestration at the global scale, to flood protection, soil formation, and nutrient cycling at the local and regional scales (Gund Institute 2007).

valuation aims to assign a monetary value to nature and the goods and services environmental resources provide. It rests on a double weakness in current policy-making, which neither gives such services their full economic weight nor accounts sufficiently for environmental damage caused by human activity. Setting monetary values for ecosystem services and for anthropogenic degradation of the environment helps create market-based mechanisms to pay for such services, or to compensate for such damages. Ecological economists currently believe this approach represents the only way to curb biodiversity loss; it situates biodiversity in economics and public policy for efficient spending decisions.

The first marine and coastal economic valuation took place in 1926, when a specialist in fisheries biology, Percy Viosca, estimated the conservation value of Louisiana's coastal wetlands. Recently, accidental marine pollution incidents have increased the need for such valuation: following the 1989 Exxon Valdez oil tanker spill in Alaska,

The loss estimates were determined through an economic analysis, largely surpassing economic losses directly due to the accident and encompassing non-market losses. The less well-known 1978 Amoco Cadiz case bolstered the need to measure the cost of ecological damage, but demands for indemnities based on economic valuations were abandoned during litigation.

the American Supreme Court fined Exxon over $1 billion in its final court judgment in 2008 for ecological losses and compensatory damages. Ecosystem valuations are currently being used to estimate the 2010 Deepwater Horizon oil spill impacts on coastal ecosystems in the Gulf of Mexico.

During the 1990s, such valuations aimed for a larger scale when a team of researchers led by Robert Costanza estimated the economic value the entire world's ecosystem services. They calculated that marine and coastal ecosystem services contributed $21 trillion dollars annually to human well-being: most (60%) of these services concentrate along coastlines that make up only 9% of the world's surface area (Costanza 1999). These coastal and marine areas - including coastal wetlands and mangroves - represent 77% of the world's total ecosystem services value (Martinez et al. 2007) (See Figure 1).

Internationally, studies of marine and coastal ecosystem services valuation are increasingly numerous: all underscore the importance of marine areas in furnishing goods and services. In the Mediterranean, they are worth nearly €26 billion annually, with cultural and leisure services providing two-thirds of that total (Mangos et al. 2010). In the United Kingdom, provisioning services are worth €713 million, cultural services €15 billion, regulating services between €840 million to €10 billion, while supporting services exceed €1 trillion in value (Beaumont et al. 2008). In these valuations, the estimated worth of "commercial" goods and services proves relatively less than that of cultural, supporting and regulating services.

In France, studies of ecosystem services valuations remain rare, and marine ecosystems valuations studies even more so. An important exception took place in 2008, when the Civil Superior Court in Paris considered the economic value of ecological damage due to the 1999 Erika oil tanker spill in its €370 million judgment against Total. The judgment included not only compensatory damages for lost commercial goods and services, but also the value of intangibles - beauty and inspiration, and more generally, the assurance of healthy ecosystems for future generations. Such valuations will probably become more common in the future. In 2009, a report by France's Strategic Analysis Council reviewed the concept of biodiversity and ecosystem services valuations, analyzing methodology along with potential applications and limitations (Chevassus-au-Louis et al. 2009). As yet, few French marine ecosystem services valuations are available, excepting one conducted through the French Initiative for Coral Reefs that valued reefs in certain "Overseas French Provinces,"

Sovereign French territory extends beyond mainland France to islands and territories in the Pacific, Atlantic and Indian Oceans, South America and Antarctica. These French "overseas" provinces are composed of different administrative entities: the most important ones for marine biodiversity are located in the Caribbean, Indian Ocean, Southern and Southeastern Pacific.

such as Martinique (see Box 1). In addition, the French Administration for Austral and Antarctic Lands launched a study in 2010 to value land and marine biodiversity, within the framework of its Biodiversity Action Plan. Although few studies have targeted its two seacoasts, France is conducting a valuation of some of its Marine Protected Areas in the Mediterranean, and of the Saint Brieuc Bay in the English Channel and Atlantic Ocean.

Assigning value to biodiversity undeniably aids efforts towards marine resources conservation and sustainable exploitation. Ecosystem services valuation provides a powerful integrated, multi-actor management tool that brings together knowledge from different disciplines - ecology, biology, economics and social sciences - and expresses it in a monetary form understood by all. It provides two crucial policy tools: means to represent the costs of marine ecosystems' degradation and destruction, and to define the "good" environmental status that the European Union's 2008 Marine Strategy Framework Directive requires by 2020 (EU 2008).

Nevertheless, ecosystem services valuation has its skeptics with regard to both its ability to supply accurate data and the use of such data. On large scales, values are often astronomically high: consequently, they are hard to compare with economic reality or to integrate in a national accounting system. Practitioners debate methodological questions, notably issues surrounding benefit transfer

"The benefit transfer method rests on a simple principle: using a valuation conducted on one site, called a 'study site,' to deduce the valuation of a second site, the 'application site'"(Rozan and Stenger 2000).

and the aggregation and use of results. Even the core principle of valuation is questioned, since studies tend to show that the more humans exploit an ecosystem, the more its economic value increases, boosted by direct use values (Failler 2010). Such results run counter to marine biodiversity management policies that tend to limit some ecosystem uses.

Ecosystem services valuation's next challenge lies in overcoming this services-based approach - so constraining in many ways - and developing an approach based directly on ecosystem functions and their interactions. This calls for an inventory of knowledge from the many disciplines involved in ecosystem valuations, one that establishes connections between fields. Beyond questions of method, however, further work must be done on how to integrate valuations into practical decision-making, making them more relevant and useful for policy-makers.

VALUE OF MARINE AND COASTAL ECOSYSTEM SERVICES

Source: Costanza (1999)
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Total Value of Martinique's Marine and Coastal Ecosystems

Source: Failler et al. (2010)
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