Environmental accounting for ecosystem conservation: Linking societal and ecosystem metabolisms

Highlights

• The notions of social and ecosystem metabolisms allow to work at different scales.

• Societal metabolism depends on the metabolic patterns of ecosystems embedding them.

• Flow-fund model allow to link the social and ecosystem metabolism.

• Metabolic pattern is used to define benchmarks for ecosystems to assess human impacts.

• Genuine impact Indicators can be produced to make diagnosis and scenarios.

Abstract

This paper proposes an approach to environmental accounting useful for studying the feasibility of socio-economic systems in relation to the external constraints posed by ecological compatibility. The approach is based on a multi-scale analysis of the metabolic pattern of ecosystems and societies and it provides an integrated characterization of the resulting interaction. The text starts with a theoretical part explaining (i) the implicit epistemological revolution implied by the notion of ecosystem metabolism and the fund-flow model developed by Georgescu-Roegen applied to environmental accounting, and (ii) the potentials of this approach to create indicators to assess ecological integrity and environmental impacts. This revolution also makes it possible to carry out a multi-scale integrated assessment of ecosystem and societal metabolisms at the territorial level. In the second part, two applications of this approach using an indicator of the negentropic cost show the possibility to characterize in quantitative and qualitative terms degrees of alteration (crop cultivation, tree plantations) for different biomes (tropical and boreal forests). Also, a case study for land use scenarios has been included. The proposed approach represents an integrated multi-scale tool for the analysis of nature conservation scenarios and strategies.

Introduction

According to the results of the Millennium Ecosystem Assessment project, the increase in well-being experienced by part of the human population in the last 60 years has been achieved at the cost of the most extensive and rapid transformation of ecosystems in human history (Millennium Assessment, 2005). This explosion human activity on the planet has led some authors to propose the introduction of two concepts: (i) a new geological era called Anthropocene (Crutzen and Stoermer, 2000, Lewis and Maslin, 2015, Steffen et al., 2015a, Steffen et al., 2011) to stress that currently biophysical processes controlled by humans represent the main driving force behind changes in the ecosystems (Zalasiewicz et al., 2008); and (ii) the notion of planetary boundaries, i.e., ecological limits for the human activity in order to operate safely within a global change framework (Rockström et al., 2009, Steffen et al., 2015b). The concept of planetary limits clashes with the economic strategy of perpetual growth, and implies acknowledging that the reproduction of the societal structures and functions depends on the integrity of ecological processes. In particular, two factors determine these limits to economic growth: its dependence on the availability of natural resources (limits of the supply capacity) and the damage that socio-economic activities implies on nature (limits of the sink capacity). For this reason, in the last decades there has been an increasing interest in developing approaches to improve the analysis of both the dependence and the impact of humans on ecosystems.

The ongoing effort to build an international framework on environmental accounting can be interpreted as a result of this interest (EEA, 2011, Obst, 2015, UN, 2014a, UN, 2014b, UN, 2014c, World Bank, 2010). This framework has the challenge to standardize the organization and presentation of useful information for characterizing the interface between the economy and the environment in order to support decision making (Vardon et al., 2016). In practical terms, this new System of Environmental Accounts is expected to complement the current System of National Accounts (UN, 2014a). This goal is approached by using two categories to define the elements describing socio-economic patterns in relation to nature: stocks of people and artefacts, and flows of energy and materials.

However, the ecosystem accounting framework developed continues to be labeled as “experimental”, indicating that no complete agreement has been reached on how to carry out such a task (Bartelmus, 2015, Bartelmus, 2014, UN, 2014b). The distinction proposed between stocks and flows have created many ambiguities when applied to multiple-scales analysis since the criteria used for defining these categories blur if non-equivalent descriptive domains and multiple boundaries are considered simultaneously (Giampietro and Lomas, 2014, Mayumi and Giampietro, 2014). Furthermore, the complex nature of the two systems analyzed implied that the methodologies proposed did not result completely satisfactory. Methodologies based on economic variables are in some cases effective in focusing on monetary benefits obtained by people exploiting ecosystems. However, they are not as effective in assessing the changes that this exploitation causes. On the other hand, methodologies based on biophysical indicators are effective in focusing on quantitative and qualitative changes suffered by ecosystems, but not as effective in assessing the consequences on the economy and the social well-being.

This dilemma points at a systemic conundrum of integrated assessment. To deal with this conundrum, it is very useful to frame the analysis of sustainability issues adopting the notion of metabolism. This concept assumes by default the co-existence of different relevant scales and dimensions of analysis (Giampietro, 2014, Giampietro et al., 2012). Thus, it becomes possible to characterize the reproduction of human societies by a continuous flow of energy and materials taken from and discarded to the environment, i.e. societal metabolism (Cottrell, 1955, White, 1943, Zipf, 1941). In the last decades, societal metabolism has been gaining momentum with the search for consistent environmental accounting methods for sustainability (Fischer-Kowalski, 1998a, Fischer-Kowalski, 1998b, Giampietro, 2014, Giampietro, 1997, Giampietro, 1994, Giampietro et al., 1997, González de Molina and Toledo, 2014, Padovan, 2000).

An important contribution to this field has been provided by the Bioeconomics framework (Georgescu-Roegen, 1971, Giampietro et al., 2012, Mayumi, 2001). The bioeconomic framework moves the attention away from an input/output analysis of the various flows of goods and services consumed and produced to an analysis of funds, or the reproduction of production factors. This distinction between flows (inputs/outputs) and funds (estructural elements) makes it possible to explictitly address the issue of scale that appears when environmental boundary conditions are considered.

The aim of this paper is to present Multi-Scale Integrated Assessment of Societal and Ecosystem Metabolism (MuSIASEM) (Giampietro, 2004, Giampietro et al., 2013, Giampietro et al., 2012), based on the flow-fund model of Georgescu-Roegen, as an approach to make integrated assessments of society and nature. To this purpose, the theoretical basis for the concept of ecosystem metabolism, and the potentials of this approach to produce integrate assessments of the societal and ecosystem metabolisms are explained in section 2. To exemplify this potential, section 3 illustrates the reproduction of biomass as a fund, and section 4 presents three examples of application of this approach aimed at generating a quantitative assessment of the alteration level for terrestrial ecosystems: tree plantations, crop cultivation, and a hypothetical case study with different scenarios of land uses.