User:Stusti-nachhaltigkeit

Sustainability economics is an emerging subfield of economics. It deals with human-nature relationships under the conditions of inherent uncertainty in the long run. These relationships are studied in view of the normative objectives of efficiency cand justice, including inter- and intragenerational distributional justice and justice towards nature. While the term "sustainability economics" is not yet widely used, there is increasing scientific interest in this discipline.

Dissociation from other disciplines
The approach of sustainability economics can be distinguished from adjacent disciplines which all lack some of its features. It can however been seen as the an intersection of Environmental economics and Ecological economics


 * Environmental science does not focus on questions of efficiency, allocation and justice and focuses mainly on the environmental aspect of the human-nature relationship, thereby neglecting economic dynamics and constraints.
 * Sustainability science does not center on the objective of efficiency

The methodology of sustainability however often combines aspects of the diciplines mentioned above, also incorporating concepts of other economic fields (such as welfare and behavioural economics), ethics, and epistemology. Furthermore, the aim of sustainability economics is to offer scientific knowledge and policy recommendations for sustainable development.

Normative foundations
Most economists consider their discipline to be a highly positive science, even though efficiency defined as nonwastefulness of scarce resources in achieving a given end can be seen as a normative foundation itself. Sustainability on the other hand clearly has normative character. In sustainability economics there is both, a descriptive interest to understand questions of efiffiency and justice, as well as an interest to influence policy and action towards its normative objectives.

Sustainability in economic terms
Rather than focusing on the so called economic dimension of sustainability, sustainability economics is a science to reach the normative objectives of sustainability by interlinking social, economic and environmental aspects of sustainability. In the case of sustainability economics, the normative objectives of sustainability are usually expressed by a combination of three different principles of justice. Intragenerational justice aims at guaranteeing just relationships within the currently living generation, while intergenerational justice is concerned with justice between the presently living and future generations. Attributing an intrinsic value to non-human nature, a category of justice towards nature is introduced.

It is difficult to translate these principles into economic terms. Different concepts have emerged: 1. result-oriented (e.g. human well-being) 2. prerequisite-oriented (e.g. capital)
 * satisfaction of basic needs (compare Brundtland-Definition of sustainability,
 * non-declining utility over time
 * "strong" rejecting substitutability between "traditional" capital stocks and natural capital: maintain (critical) capital stocks
 * "weak" assuming this substitutability: maintain aggregate value of capital,

Further problems well known from traditional economic theory are the measurement of utility, fullfillment of basic needs, and social welfare.

Time horizon and uncertainty
Special attention must be paid to uncertainty, especially since questions of sustainability typically deal with long time horizons. Uncertainty can be grouped in three categories: While dealing with the weakest form of uncertainty, risk, is widely understood and used in economics, more realistic models have to incorporate unknown probability and even unknown outcomes.

Due to its focus on the questions of intergenerational allocation and justice, sustainability economics deals with problems of intertemporal choice.

Discounting
The discounted-utility (DU) model is widely applied in standard economics to calculate the present value of future outcomes. The discount factor indicates whether a higher value is assigned to the present (< 0) or the future (> 0); or if they obtain equal appreciation. It can be related to both, prescriptive and descriptive research questions. While the first imposes a normative imperative, the latter portrays empirical intertemporal decisions with respect to either individuals or the society. With respect to sustainability economics, the general effect of discounting is that future utility is transfered to the present while present damage is postponed to the future. However, studies in behavioral economics have revealed a variety of anomalies such as preference reversals, subadditive discounting, loss and inequality aversion. These anomalies involve "irrational" time inconsistency. Hyperbolic_discounting uses diminishing discount factors instead of constant ones and thereby meets empirical results better and prevents the almost-zero appreciation of future outcomes in the long run due to the compound-interest problem.

Decision under risk
Economic models can only cope with risk. Therefore, in the common event of uncertainty, subjective probabilities have to be used. If future costs or utility are unknown, this fact has to be taken into account in an appropriate manner through the usage of social or individual risk preferences. Following the expected utility theory, risk-averse individuals evaluate their liking of riskless outcomes over lotteries by the means of a risk premium. In the face of uncertainty, many people assign a higher value to information, flexibility, and insurance services, thereby possibly setting an incentive to postpone projects with uncertain outcomes. This mechanism works against uncertain projects for both environmental protection and environmental destruction.

Human-Environment Relationship
As in the related fields of ecological economics and sustainability science, human-nature relationship is a focus of sustainability economics. Traditional environmental and resource economics tend to reduce these relationships to use natural resources and external effects such as pollution. More recent models pay attention to complex relationships such as ecosystem services.

Giving account to the complexity of environmental and human-nature systems and uncertainty, sustainability economics does also analyse the conditions and mechanisms that affect social, economic and political stability of human-environment systems, vulnerability and systemic risks. Concepts to deals with this problems are for example resilience and viability.

Critique
One major point of criticism regarding sustainability economics is the overall vagueness which is linked to this discipline and the debated concept of sustainability. Further criticism stems from the fact that sustainability economics remains dependent on contestable economic mainstream concepts, e.g. the one of the rational acting Homo economicus. Offene Fragen, was fehlt? - policy recommendations / options (Erkenntnisse der Verhaltensökonomie verbinden mit Einsichten aus Modellen und - "politische Nachhaltigkeitsökonomie" - Modelle basieren weiterhin auf "Mainstream"-Annahmen der VWL (Homo Economicus, Substituierbarkeit (?))