HAL Id: hal-02805533
https://hal.inrae.fr/hal-02805533
Submitted on 6 Jun 2020
HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci- entific research documents, whether they are pub- lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.
L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Entre propriétés des écosystèmes et bénéfices pour la société : l’évaluation économique des services fournis
par les écosystèmes prairiaux
Jean-Michel Salles
To cite this version:
Jean-Michel Salles. Entre propriétés des écosystèmes et bénéfices pour la société : l’évaluation économique des services fournis par les écosystèmes prairiaux. Séminaire du Réseau Prairies “ l’évaluation des services fournis par les prairies, un défi interdisciplinaire entre propriétés des écosys- tèmes et bénéfices pour la société ”, Dec 2013, Clermont-Ferrand, France. �hal-02805533�
Entre propriétés des écosystèmes et bénéfices pour la société : l’évaluation économique des services fournis par les écosystèmes prairiaux
Jean-Michel Salles
CNRS, UMR LAMETA, Montpellier, France
17-18 Décembre 2013
L’évaluation des services fournis par les prairies
Séminaire Réseau Prairies : Campus VetAgro-Sup Lempdes
Services écosystémiques et sciences sociales
• Les approches des services écosystémiques par les sciences sociales renvoient à une pluralité d’approches disciplinaires :
– Philosophie : fonder nos jugements, fonder nos actions
– Anthropologie : comprendre la nature, notamment symbolique, des relations culture-nature
– Sociologie : liens entre les représentations et les stratégies des acteurs – Droit : statut juridique des relations à la nature, prise en charge par le droit – Sciences politiques : étude des choix publics, formation de groupes d’interêt – Économie : caractérisation de l’efficacité sociale, “implémentation” d’objectifs
• Cette pluralité d’approches relève de deux perspectives fondamentales, partiellement dépendantes :
– Positive : comprendre la nature et l’importance des relations entre sociétés et natures à travers le prisme de la notion de service, ainsi que le niveau et les conditions de maîtrise des sociétés ou des acteurs sur ces relations
– Normative : juger/évaluer l’importance de ces relations pour mieux les gérer, en termes d’objectifs, de moyens , de politiques publiques
Services écosystémiques et sciences sociales
• La perspective positive peut considérer la question de la relation des sociétés à la nature de plusieurs façons :
1. Nature (Société) 2. Nature > société 3. Société = nature 4. Société > nature 5. Société (Nature)
• Au moment des choix et des comportements, le rapport à la nature n’est qu’une partie des enjeux pris en compte… parfois marginalisée
• Les notions de valeurs sont omniprésentes… avec des contenus, des sens différents selon les lieux, les moments
• Dans une perspective normative, le lieu où se fondent les valeurs dominent celui où elle s’appliquent.
• En amont, certains travaux (philosophie, anthropologie) s’efforcent de comprendre sur quoi se fondent nos valeur
Social science and ecosystem services
• On distingue deux grands types de valeurs :
1. Les valeurs instrumentales : les écosystèmes ou leur diversité sont considérés comme des moyens mobilisables pour servir d’autres fins, ils sont vu comme la source de services contribuant au bien-être
humain ou social
2. Les valeurs intrinsèques : la nature a une valeur en soi, indépendam- ment de toute utilisation et, même, de tout évaluateur extérieur
• Les éthiques classiques n’accordent de valeur intrinsèque qu’aux seuls humains. Les “éthiques environnementales” ont largement débattu de la possibilité et des conséquences de reconnaître une valeur intrinsèque à des entités non-humaines, pouvant impliquer la reconnaissance de
droits aux êtres vivants, et une responsabilité morale à l’homme à protéger la nature et les écosystèmes.
• La question renvoie donc à un débat plus large sur l’anthropocentrisme, par opposition au bio-centrisme ou à l’éco-centrisme
Evaluer les écosystèmes et la biodiversité
• Individuals are considered the best judges of their “preferences”
- How to deal with “non familiarity”…
- and biased preferences (like with “Merit goods”)
évalue la biodiversité
On the meaning of economic valuation
• The economic concept of value:
Anthropocentric (anthropogenic?)
Instrumental: values reflect the contribution of choices (options) and related assets to an end/goal which is not judged/assessed
Consequentialist (≠ deontological ≠ virtue)
Utilitarianism / welfarism:
- An arithmetic of pleasures and pains (=> cost-benefit analysis) - Based on the sum of individual utilities, not their distribution
Marginalism: valuation rests on comparison, not measurement (ordinal vs cardinal approaches of utility)
Subjectivity:
- Individuals are considered the best judges of their “preferences”
- How to deal with “non familiarity”…
- and biased preferences (like with “Merit goods”)
The incommensurability issue
The incommensurability debate
• Can all the choices and assets that contribute to a “good life”
really be compared? Made commensurable?
• Is Nature substitutable ?
• Concept of « critical natural capital »
behind a minimum level, the « natural capital » is no longer substitutable, but complementary with the other factors that contribute to production and welfare
• The value of any object depends upon its utility and its scarcity
• Is biodiversity useful? Is all the biodiversity useful?
• Is biodiversity scarce? There is generally a positive willingness to pay to prevent its degradation
Valuing biodiversity: what can be valued?
• Which object ?
• The diversity of life
• Genes, Species
• Habitats, landscapes, Ecosystems functions
• Valuing ecosystem services
• More easily understandable by users… and by economists
• Easier elaboration of equivalence classes
• The Millenium Ecosystem Assessment (2005) created a certain consensus (provisory)
“Ecosystem services : From eye-opening metaphor to complexity blinder” (Norgaard, 2010)
• Service écosystémiques, environnementaux, écologiques ? Westman (1977) : services rendus par la nature = avantages pour les humains
“Measuring the social benefits of ecosystems functioning is both controversial and illuminating”
Ecosystems services and their links with human welfare
Freedom of
choice and action implies the
existence of alternatives at several levels:
- technical, - political, - economic, - cultural…
It should be integrated in the analysis of
economic values
Relations between the different ecosystem services categories and the land uses (MSA = Mean Species Abundance)
• Source : Braat et Ten Brink, 2008
• Débat : les relations entre la conservation des services écosystémiques et la préservation de la nature ou de la « biodiversité » sont ambivalentes
From ecosystem structure and process to economic value
1) One function is often involved in the provision of several services and the use of services usually affects the underlying biophysical structures and processes in multiple ways.
Ecosystem service assessments should take these feedback-loops into account
The cost of inaction: building scenarios
Building economic and political scénario to compare the evolution of ecosystem services and the cost of biodiversity losses
Do we really care about biodiversity?
Source : D. Pearce (2007)
Is “No net biodiversity loss” an acceptable or sound objective ?
Total costs
« Total » benefits
Monetary benefits
ESopt ESmin ESma
Technical costs Opportunity costs
ES = ecosystem services Avantages
et coûts marginaux
Les composantes de la valeur économique totale : synthèse ?
Source : CAS, 2008
Nonanthropocentric values
Instru
mental values
Intrinsic values
• Interests of entities for themselves and for the communities they belong
•Inherent values, independant of any evaluator
Total economice value of natural assets : open questions
• Since their introduction by J.V. Krutilla (1967), the interpretation of existence values evolved :
– From willingness to pay for consevation, without any use perspective – Towards the expression of altruism and responsibility ("stewardship")
• Non-use values and intrinsic values
from anthropocentrism to anthropogenic values ?
• Economic values or the purchase of moral satisfaction (Kahnemann &
Knecht, 1992) ?
• Are economic agents altruistic consumers or citizens with ethical commitments (Sen, 1987) ?
• Do agents have prior preferences for any asset (Plott, 1996), or do they construct them in the valuation process (Slovic, 1996)
Many valuation methods…
1. Cost based methods:
Monetising bio-physical damages
Impact on production functions
Restoration costs (?)
Replacement costs (?)
1. Methods based on revealed preferences:
Prevention or protection costs
Travel costs method
Hedonistic prices
1. Methods based on stated preferences:
Contingent valuation method (direct WTP)
Choice modelling, joint analysis (indirect)
1. Benefit transfers
From one study or from a meta-analysis
Transferring a cost function rather than a value
Available data bases (EVRI, Envalue, ESD…)
All these approaches meet strong limits
• Informational limits and “systemic errors”:
• Cost-based methods must be framed by social values (if restoring an ecosystem costs 10 time the WTP of the concerned population, restoration is inefficient)
• Revealed preferences methods capture only some aspects of the total value and indicate only some specific use values (recreation, aesthetic…)
• Stated preferences methods often encompass systemic errors (hypothetic bias, strategic declarations, “embeddedness”…)
• Evaluators are confronted to the dilemma of choosing between:
• More robust methods (there are observable costs or behaviours) measuring limited values (use values) or controversial
• Wider scope approaches (the whole TEV can potentially be identified) ; but poorly reliable (since based on the statements of possibly poorly or mis-informed agents)
• Benefit transfers constitute a perspective of practical interest, but remains poorly reliable, especially since the basic studies have not been designed in the
perspective of being transferred
• Decision making without valuation?
– Decisions follows the preferences of the Prince ? The interests of the strongest lobbies ? The dominant ideology or the custom of the day ?
– Decisions are made by elite, technocrats and experts (better educated and informed) that know, better than population, where are the main issues?
Dealing with time and uncertainty
• Time appears in economic analysis through the question of discounting (the current public discount rate is lower than in the past : 4%)
• The long run (over 30 years) is better taken into account with decreasing discounting rates ( « hyperbolic » or “Gamma” discounting)
• Discounting is related to values, utilities: it is then compulsory to make assumptions on the evolution of relative prices (including shadow prices) in the long run :
– Decreasing trend for manufactured products (technical changes)
– Increasing trend for ecosystems and biodiversity that reflects increasing
scarcity and growing demand (income elasticity for environment demand > 1)
• For irreplaceable assets, the “Hotelling rule” may apply (implicit price increasing at the discounting rate pace) ;
– for services with indefinite time prospect it may lead to infinite values
• The uncertainties on the dynamic of ecosystem services and the future social demand may give a great importance to option values…
– but let their practical quantification very difficult, if not unrealistic
Limits et controversies
• Despite provocative publications (Costanza et al., 1997), the “value of the world ecosystem services and natural capital” remains poorly defined and has probably no economic meaning
• The TEEB study (The Economics of the Ecosystems and Biodiversity, P. Sukhdev, 2008-2011) that aimed to produce such an estimate,
based on worldwide land use scenarios, finally gave up this objective (initially inspired from the “Stern Review on Climate Change) and limited its scope to a wide scientific review and recommendations to policy-makers, from international to local scale, firms and citizens.
• It appears more realistic to quantify and value the services provided by (actually taken from) well-defined units of ecosystems (or lost from their degradation or destruction)
• Hectare after hectare, our world irreversibly changes and it is really difficult to identify thresholds for catastrophic dynamics and costs
• The economic value of ecosystem and ES may remain limited (because of the resilience of ecosystems and anthroposystems), as long as the situations avoid collapses (see J. Diamond, 2005)
“Ecosystem services” and “PES”
• Un mécanisme défini par des conversationnistes qui, dans les années 1990, font le constat que les programmes de conservation et
développement intégré ne font de la conservation que par
« distraction » (par mégarde)
• Les chercheurs qui travaillent ensuite sur ces mécanismes (Wunder, Pagiola, Engels, Landell-Mills …) ne sont pas les même que ceux qui ont travaillé sur les services écosystémiques ou leur évaluation
(Costanza, de Groot, Christie…)
• Pourtant Gomez-Baggethun et al (2010) présentent les PSE comme une finalité naturelle de l’évaluation des SE
• Pas de raison de les croire car les mécanismes de PSE ne se calent pas sur la valeur des service (qui ne dépend pas de l’offreur), mais sur les coûts d’opportunité qu’il supporte pour garantir leur
disponibilité/production
Quelles perspectives pour les services écosystémiques?
Normative science et policies : Science never says what we have to do
Valuing ecosystems and biodiversity is a political choice grounded on the belief that we are living in a finite world with increasing scarcities (more numerous and hopefully wealthier people) that will imply increasingly conflicting choices
Valuing ecosystems biodiversity does not imply that nature will or should become a market good, and values don’t aim at becoming the prices of ecosystem destruction allowances
A better management of « ordinary biodiversity » is a top priority,
and valuing ecosystem services may contribute to achieve this objective in a more efficient, and possibly fairer way, in all cases more conscious and, hopefully within a democratic deliberative process
The economics of ecosystem services is eventually too serious to be entrusted to the (sole) economists… but it would be unreasonable to pretend achieving economic valuation without economists.
Why valuing biodiversity?
« If our purpose is to conserve these (ecosystem) services, valuation is to a large extend non pertinent. (…) in the matter of nature protection, valuation is neither necessary, nor sufficient.
We conserve many things that we don’t evaluate and little of those we value » (Geoffrey M. Heal)
Thank you for your attention
Ecosystem services and social sciences
• Linking biophysical aspects of ecosystems with human benefits through the notion of ecosystem services is essential to assess the trade-offs (ecological, socio-cultural, economic and monetary) involved in the loss of ecosystems and biodiversity in a clear and consistent manner.
• Any ecosystem assessment should be spatially and temporally explicit at scales meaningful for policy formation or interventions, inherently acknowledging that both ecological functioning and economic values are context, space and time specific.
• Any ecosystem assessment should first aim to determine the service delivery in biophysical terms, to provide solid ecological underpinning to the economic valuation or measurement with alternative metrics.
• Clearly delineating between functions, services and benefits is important to make ecosystem assessments more accessible to economic valuation, although no
consensus has yet been reached on the classification.
• Ecosystem assessments should be set within the context of contrasting scenarios - recognising that both the values of ecosystem services and the costs of actions can be best measured as a function of changes between alternative options.
- Individuals are considered the best judges of their “preferences”
- How to deal with “non familiarity”…
- and biased preferences (like with “Merit goods”)
Ecosystem services and social sciences
• In assessing trade-offs between alternative uses of ecosystems, the total bundle of ecosystem services provided by different conversion and management states
should be included.
• Any valuation study should be fully aware of the „cost side of the equation, as ‟ focus on benefits only ignores important societal costs like missed opportunities of alternative uses; this also allows for a more extensive range of societal values to be considered.
• Ecosystem assessments should integrate an analysis of risks and uncertainties, acknowledging the limitations of knowledge on the impacts of human actions on ecosystems and their services and on their importance to human well-being.
• In order to improve incentive structures and institutions, the different stakeholders - i.e. the beneficiaries of ecosystem services, those who are
providing the services, those involved in or affected by the use, and the actors involved at different levels of decision-making - should be clearly identified, and decision making processes need to be transparent.
Why biodiversity is so important for our societies
• The first difficulty, to perceive socioeconomic stakes related to biodiversity, is to identify the whole extension of its presence in the daily life of human being:
biodiversity is everywhere, from food production to digestion, from skin préservation to chemical industries, etc.
• Ecosystem services result from the interactions between organisms that shape the environment and ecosystem functionning. Air and water purification, carbone storage, soils fertility are services that result of organisms interactions
• The Millenium Ecosystem Assessment proposed a classification of ecosystem services in 4 main groups
•
