A Matter of Opinion: How Ecological and Neoclassical Environmental Economists Think about Sustainability and Economics

Abstract

The differing paradigms of ecological and neoclassical environmental economics have been described in various articles and books and are also embedded in different professional associations. However, we cannot take for granted that the paradigm debates described in the literature are actually mirrored in exactly the same way in the perceptions and opinions of researchers looking at sustainability from an economic perspective. This paper presents empirical results from a German case study on how economists and others involved in sustainability research from different schools of thought think about the issues of sustainability and economics, how they group around these issues, how they feel about the current scientific divide, and what they expect to be future topics of sustainability research.

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SURVEY
A matter of opinion—How ecological and neoclassical
environmental economists and think about sustainability
and economics
Lydia Illge
a,
⁎, Reimund Schwarze
b
a
IZT Institute for Futures Studies and Technology Assessment, Schopenhauerstrasse 26, 14129 Berlin, Germany
b
UFZ Helmholtz Centre for Environmental Research, Permoser Strasse 15, 04318 Leipzig, Germany
ARTICLE DATA ABSTRACT
Article history:
Received 13 September 2005
Received in revised form
8 August 2008
Accepted 11 August 2008
Available online 17 October 2008
The differing paradigms of ecological and neoclassical environmental economics have been
described in various articles and books and are also embedded in different professional
associations. However, we cannot take for granted that the paradigm debates described in
the literature are actually mirrored in exactly the same way in the perceptions and opinions
of researchers looking at sustainability from an economic perspective. This paper presents
empirical results from a German case study on how economists and others involved in
sustainability research from different schools of thought think about the issues of
sustainability and economics, how they group around these issues, how they feel about
the current scientific divide, and what they expect to be future topics of sustainability
research.
We analyze the data using cluster analysis. Based on a literature survey, we generated forty
sustainability economics-related statements and asked 196 sustainability researchers about
their degree of agreement or disagreement with these statements. In evaluating our survey
results, we discuss to what extent the clusters that we identified do—or do not—represent
the two schools of thought of ecological and neoclassical environmental economics. We also
propose some fields of research that can help to bridge the gaps amongst sustainability
economics researchers while clearly marking others that are more suitable for a scientific
‘competition of ideas’. Key results of the study are: We identify two primary scientific
clusters, one clearly confirming the existence of the ecological-economics school of thought,
and the other largely capturing the neoclassical environmental view. Yet, there are some
surprising exceptions: Both schools of thought share a conceptual definition of
sustainability that is integrative in considering ecological, societal and economic
dimensions (‘three pillar concept’) and is geared at preserving the development potentials
of society. We also find a shared critique of ‘pure economic growth’strategies in our sample.
These shared opinions may provide bridging concepts between the schools of thought. Also
both clusters agree with respect to a wide range of future fields of sustainability economics
research. Yet, the research agenda of the ecological-economics cluster contains a large
number of additional topics, primarily related to social, distributional and evolutionary
aspects of sustainable development. Strong divides between the clusters that seem to be
Keywords:
Sustainability
Ecological economics
Neoclassical economics
Research prospects
Cluster analysis
Questionnaire
ECOLOGICAL ECONOMICS 68 (2009) 594–604
⁎Corresponding author. Tel.: +49 30 80 30 88 34; fax: +49 30 80 30 88 88.
E-mail address: l.illge@izt.de (L. Illge).
available at www.sciencedirect.com
www.elsevier.com/locate/ecolecon
0921-8009/$ –see front matter © 2008 Elsevier B.V. All rights reserved.
doi:10.1016/j.ecolecon.2008.08.010

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more suitable for a scientific competition of ideas are primarily related to the question of
how to achieve sustainability, including appropriate environmental policies.
© 2008 Elsevier B.V. All rights reserved.
1. Introduction
In an international workshop on future topics for sustain-
ability economics research held in Berlin in 2003,
1
the
participants got involved in a heated discussion about
whether economic growth is a desirable goal for the sustain-
able development of nations. From their pro and con
arguments, the sustainability researchers could be easily
assigned to the two competing sustainability paradigms of
ecological economics and neoclassical environmental eco-
nomics. It turned out that both groups of researchers did not
realize that they were talking about two different things when
they mentioned the term ‘economic growth’. Whereas some
referred to a rather physical concept of economic growth
associated with an increasing use of material resources and
the increasing generation of emissions and waste, others had
a monetary concept of growth in mind that could be measured
through GDP (or GNP) and would not necessarily bring about
increasingly negative environmental effects. In the end,
everyone agreed that a kind of decoupling of economic
activities from harmful environmental effects is a desirable
goal. However, opinions differed strongly on how to achieve
such a development.
The differing paradigms of ecological and neoclassical
environmental economics that more or less clashed at our
Berlin workshop have been previously described in various
articles and books (e.g., Martinez-Alier, 1990; Costanza, 1991;
Klaassen and Opschoor, 1991; Söderbaum, 1992; Munda, 1997;
Beckenbach et al., 1999; Van den Bergh, 2000; Daly and Farley,
2003; Hubacek and Van den Bergh, 2006). They are also
embedded in different institutional settings. In a European
context, neoclassical environmental and resource economists
have joined together in the European Association for Environ-
mental and Resource Economists (EAERE), whereas ecological
economists are organized in the European Society for Ecolo-
gical Economics (ESEE). A similarly divided structure can be
found in Germany. On the neoclassical side there is the group
of environmental and resource economists within the German
Economic Association (VfS), while on the ecological-economic
side are the Association for Ecological Economics (VÖÖ) and
the Association for Ecological Economic Research (VÖW). As a
consequence of such institutional segregation, each paradigm
has it own publication media (typically environmental-
economic mainstream and ecological-economic side stream
2
journals) as well as parallel institutional structures at uni-
versities (e.g., chairs for environmental and resource econom-
ics and others for sustainable development). This divide is an
ambivalent phenomenon from a science policy perspective.
On the one hand, it may help (the still young) scientific
discipline of ecological economics to develop their own
concepts and tools. On the other hand, valuable scientific
synergies within economics may remain untapped.
The literature mentions a large variety of watershed topics
that divide neoclassical and ecological economists, which can
be summarized under the following categories: concept of
human behavior (homo economicus/homo politicus/homo
sustinens; e.g., Costanza et al., 1993; Norton et al., 1998;
Røpke, 1999; Van den Bergh et al., 2000; Siebenhüner, 2000), the
bio-physical vs. monetary or integrated assessment of ecosystem
services (e.g., Pearce and Turner, 1990; Solow, 1993; Pearce and
Atkinson, 1993; Functowicz and Ravetz, 1994; Munda et al.,
1994; Faucheux and O'Connor, 1997; Martinez-Alier et al., 1998;
De Groot et al., 2002; Sagoff, 2008), judgments about the rela-
tionship between sustainable development and growth (e.g., Daly,
1991; Norgaard, 1994; Munda, 1997; Van den Bergh, 2000;
Amigues et al., 2004; Munier, 2006), as well as varying
emphases on issues of distribution and justice (e.g., Daly, 1992;
Ekins and Max-Neef, 1992; Howarth, 1992; Pezzey, 1992;
Martinez-Alier and O'Connor, 1999; Weimann, 1999; Marti-
nez-Alier, 2002; Ikeme, 2003). We also find differences related
to the scientific concept of economics (e.g., Pearce, 1987; Functo-
wicz and Ravetz, 1990; Klaasen and Opschoor, 1991; Söder-
baum, 1992; Costanza, 1993; Van den Bergh, 2000; Gowdy,
2005; Erickson and Gowdy, 2005) and different recommendations
for sustainability policy (e.g., Norton et al., 1998; Van den Bergh
et al., 2000; Kirton and Trebilcock, 2004; Lopez and Toman,
2006; Myers and Raffensperger, 2006).
Yet, are all of these topics equally strongly divisive or can
we distinguish between key divides on the one hand and
somewhat less differentiating issues on the other? And, asides
from the divisions and disagreements, are there also bridging
concepts related to sustainability, shared by both schools of
thought? We cannot take for granted that the paradigm
debates described in the literature and the institutional
divides are actually mirrored in exactly the same way in the
perceptions and opinions of sustainability researchers.
This paper presents empirical results of a German study,
based on a survey concerning how economists (and others
involved in sustainability economics research) from different
schools of thought think about the issues of sustainability and
economics, how they group around these issues, how they feel
about the current scientific divide, and what they expect to be
future topics of sustainability research. While we acknowledge
that looking at the opinions of only German researchers
somewhat limits the scope of our study, we think that these
results are of interest to the international scientific community
because they reveal two general scientific clusters that we
assume to be found in other countries as well. Based on the
survey results, we discuss to what extent the scientific clusters
that we identified do—or do not—represent the two schools of
1
Workshop reports are available at www.sustainabilityeco-
nomics.de.
2
The metaphor of ‘side stream’may not satisfy all readers since
side streams typically flow into the mainstream. Yet, we think
that it is a useful picture for describing the current situation,
assuming that ecological economics has a potential influence on
future research in traditional environmental economics.
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thought of ecological and neoclassical environmental econom-
ics. We also propose some research fields thatcan help to bridge
the gaps amongst sustainability economics researchers as well
as others more suitable for a scientific ‘competition of ideas’.
The paper is organized as follows: In Section 2, we describe
our sampling and survey methodologies. Section 3 describes
the ‘opinion sets’(clusters) about sustainability that are held
by the identified clusters of researchers, Section 4 shows how
the scientific divide is perceived within the clusters, and
Section 5 presents the perspectives on sustainability research
as seen by the study participants. Finally, we summarize our
findings and draw conclusions on the science policy implica-
tions of the divide with respect to the future of sustainability
research.
2. Sampling and survey methods
The target groups of the study were not only economists in
Germany who deal with issues of sustainability, but also other
sustainability researchers who look into economic research
questions without being economists themselves. Such a broad
definition of the target group appeared to be reasonable, as
sustainability research is typically interdisciplinary. Since we
could not include all researchers in Germany dealing with
sustainability research due to resource constraints—and since
there is no such thing as ‘the representative sustainability
economist’—we selected those ecological-economic and neo-
classical-economic associations that we consider to be the
‘focal points’of the scientific divide described in the literature.
On the one side are the German Economic Association (VfS)
and its section for Environmental and Resource Economics
(AURÖ), labeled ‘Group A’.
3
On the other side are the
Association for Ecological Economics (VÖÖ), the Association
for Ecological Economic Research (VÖW), and German mem-
bers of the International Society for Ecological Economics
(ISEE), labeled ‘Group B’.
4
All members of both AURÖ and VÖÖ
were invited to participate in the survey. Because of their large
size we took random samples of VfS and VÖW, each of a size
that resulted in a roughly equal distribution of both group A
and group B within the total survey sample.
All participants were asked to fill out a questionnaire about
various issues related to sustainability and economics (listed in
the annex to this paper). Of the 396 questionnaires given out, we
received 196 completed questionnaires back. The return rate of
49.5% can be considered high. Based on the membership
affiliations indicated by the participants, we assigned them to
groups A (71 persons) and B (79 persons), which we assume to
reflect the two schools of thought. Another group contains 24
persons with multiple memberships, whereas 22 participants
did not provide any information on their memberships.
Considering this distribution, we had a roughly equal share of
members from the various associations in our study sample—
what we perceive as a stratified sample of members of both
schools of thought in Germany.
An important implication of our sampling procedure is that
the results we present are not representative for all those who
do economic research on sustainability. Instead, our results
mirror the views of members of selected scientific associa-
tions in our study that to our opinion reflect the scientific
divide described in the literature. Thus, the question that we
study in this paper is whether and how this institutional
divide is reflected in the thinking of the members of these
institutions. While the first part of this question seems to have
an obvious answer—because membership in an association is
a willful decision of individuals to join a group of people who
share aims and values, we cannot simply conclude from
‘membership’on ‘beliefs’. Although this is in many respects a
far stretch, we use the analogy of the catholic church here to
support our point: Even though it is the official ‘policy’of the
catholic church to not allow women to become priests, there
may still be (many) members of this church who believe that
women should be allowed so. Thus, we cannot conclude from
the institution's beliefs on the beliefs of (all) its members.
Indeed, we find evidence in our study for opinions of sus-
tainability economics researchers that differ from the theore-
tical paradigms.
In the questionnaire, the participants were asked for their
personal perception and opinion about the scientific divide
within economic sustainability research and the perspectives
of sustainability economics. These results were evaluated by
using standard statistical procedures to identify sets of
opinions forming ‘clusters of beliefs’. These clusters provide
the ‘heart’of our analysis and prove to be more than just a
mirror image of the institutional groups A and B (as will be
discussed in Section 3). The clusters in our study were
identified as follows: In the questionnaire, the study partici-
pants expressed the degree of their personal agreement with
40 statements on sustainability on a scale ranging from +2
(strongly agree) to −2 (strongly disagree). The statements on
sustainability were generated based on a literature survey and
a number of pre-tests. In the pre-tests, we used the ques-
tionnaire with small groups of persons and carried out
statistical analysis in order to filter out those statements
that cause a high variance, that is, particularly contrary
opinions within the test groups.
We evaluated the participants' statement rankings by
means of cluster analysis (Centroid analysis, combined with
Varimax rotation). In doing so, the ranking results of each
participant were correlated with those of all others, identify-
ing those ranking patterns (clusters) that are typical for one
group of participants but significantly different from ranking
patterns of other groups. We ran the cluster analysis for the
versions of two, three, four and five possible clusters. While all
versions turned out to be acceptable from a statistical
perspective, the lowest value of highest cluster correlation
(0.358) was achieved by a simple two group clustering (see
Table 1). This result is in favor of version ‘two clusters’since
high correlations indicate a relatively large overlap between
the clusters. We also carried out a ‘scree test’, evaluating the
eigenvalues of all clusters. In the test, we looked for the place
where the slope of the eigenvalue function changes from
3
VfS stands for ‘Verein für Socialpolitik’(and AURÖ for its
‘Ausschuss für Umwelt-und Ressourcenökonomie’(see: www.
socialpolitik.org). VÖÖ stands for ‘Vereinigung für ökologische
Ökonomie’(www.voeoe.de), whereas VÖW is the acronym of the
‘Vereinigung für ökologische Wirtschaftsforschung’(www.voew.de).
4
We only included those German members of ISEE that were
not at the same time members of VÖÖ or VÖW.
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being steep to being flat (cp. Cattell, 1966). This test also
suggested extracting two clusters.
3. Clusters in sustainability economics
The two clusters that we identified can be described by sets of
characteristic statements related to sustainability and eco-
nomics. We derived these distinct ‘opinion sets’using those
statements of the questionnaire that the representatives of a
cluster either agreed or disagreed with the most, i.e. state-
ments with a cluster score of more than +1 or less than −1.
Since we found not only differing opinions but also a number
of statements that both clusters share, we will present the
common ground first.
3.1. Common ground of the clusters
As common ground we consider those statements with
rankings being not indifferent (that is, ranked equal to/higher
than +1 or equal to/lower than −1) and showing in the same,
direction’for both clusters (e.g., −1.4 for cluster 1 and −1 for
cluster 2). We find that clusters 1 and 2 agree largely in their
understanding of sustainability as a multidimensional con-
cept (ecological, social, economic) and agree about a sustain-
ability concept based on maintaining ‘development
potentials’for future generations. They also do not see
economic growth as being the ultimate answer to distribu-
tional conflicts within and between generations.
Broad consensus amongst sustainability researchers exists
also in seeing sustainability as an important field of research
in economics that needs to be approached with interdisci-
plinary methods. Furthermore, both clusters have a positive
attitude towards applied economic research with a clear
political outreach. Finally, both clusters are sceptical about
the possibility to figure out what resources are indispensable
for humankind for an indefinite time span.
All common ground statements are summarized in Box 1.
3.2. Cluster 1 ‘ecological economics’
Corresponding with the common ground, representatives of
cluster 1 strongly support an integrated concept of welfare,
including not only economic but also ecological and social
aspects. Further, the economy is seen as being dependent for
its existence on the ecosystem. Nature appears to be sub-
stitutable by human-made capital only to a very limited extent
and its services cannot be valued through monetarization.
Creating private property rights over the environment is seen
as being little suited towards achieving sustainable solutions.
A concept of human behavior based on individual self-interest
(‘normative individualism’in the sense of Hayek, 1948) appears
to representatives of cluster 1 as not being suitable for studying
issues of sustainability. They also support the idea of changing
individual values as part of a strategy towards sustainability.
Cluster 1 consequently disagrees with the idea of a ‘value-free’
economics. Rather, ethical dimensions should be part of
economic thinking about sustainability.
The original statements that are particularly typical for the
‘ecological economics’cluster are summarized in Box 2.
Based on our literature survey, the ‘opinion set’described so
far (consisting of both common ground and distinct statements
for cluster 1) canbe assigned to the ecological-economics school
of thought. With 105 persons, about half of all participants (54%)
are characteristic for this cluster. The German ecological-
economic associations make up for the largest part of cluster
representatives (jointly about 75%). Interestingly, there is not
only a decentshare of ISEE members in this cluster (as might be
expected) but also a sizeable group of members of the German
economic association (VfS), each about 25%).
5
However, VfS
members in this cluster are mostly not at the same time
members of the VfS section for environmental and resource
economics (AURÖ).
Box 1
Common ground of the clusters
Concept of sustainability: Sustainability means preserving
development opportunities for future generations. Extending
the sustainability concept to also include social and economic
dimensions does not dilute the normative power of the
sustainability concept.
Substitution and valuation of nature: It is not possible to
determine for an unlimited time-horizon which resources will
be indispensable for humans.
Sustainability policy: The basic conflict between efficiency
and equitable distribution can ultimately be solved not only
through economic growth.
Scientific concept: Sustainability is an important future field of
economic research. Sustainability research must overcome
the disciplinary boundaries. The political outreach of eco-
nomic analysis is not an obstacle to generate sound
economic theory.
5
Please note that membership in more than one association is
possible. Thus, percentages add up to more than 100%.
Table 1 –Key data of cluster analysis
Alternative Y2
Clusters
3
Clusters
4
Clusters
5
Clusters
Share of defining
variables (total for
all clusters) (%)
88 84 81 74
Average reliability
coefficient
0.800 0.800 0.800 0.800
Lowest value of
composite reliability
0.996 0.978 0.981 0.970
Highest value of
standard error of
cluster loads
0.062 0.149 0.137 0.174
Highest value of
standard error of
differences in
normalized cluster
loadings
0.088 0.211 0.177 0.246
Highest value of
correlation between
cluster loadings
0.358 0.523 0.553 0.544
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3.3. Cluster 2 ‘open-minded neoclassical environmental
economics’
Persons representing cluster 2 reject seeing intra-generational
justice as being a prerequisite of intergenerational justice.
They disagree with the ‘sustainability concept’of non-declin-
ing utility over time (as outlined in Solow, 1993). Strong
commonalities within this group are related to sustainability
policy. Here, both fundamental changes of the economic
system and restrictions of material consumption are rejected.
Instead, representatives of this cluster support setting the
‘right’prices for environmental goods (as a key element of
sustainability policy), and they support international specia-
lization as a means towards achieving the goal of sustainable
welfare worldwide. Representatives of cluster 2 also support
the idea of an objective economic science. Interestingly, we
find no strong opinions, but rather indifference concerning the
explicitly valuation-related statements in this cluster (related
to nature, sustainability policy and the scientific conception of
economics) that we found for the first cluster (see Box 2).
Cluster 2 largely corresponds with neoclassical economics
as described in the literature. Yet, considering both common
ground and distinct statements for cluster 2, we find four
important exceptions, most of them being conceptual. The
cluster rejects a Solow-type sustainability concept based on
non-declining utility, accepts a multidimensional sustainabil-
ity concept (ecological, social, economic), and agrees with a
sustainability concept based on maintaining development
potentials. Treating issues of intergenerational distribution in
a model of non-declining individual welfare over infinite
periods and using a single-dimensional utility- or even
money-based concept of sustainability is often seen as being
typically neoclassical (Pezzey, 1992, Weimann, 1999), but is not
shared by our second cluster.
The cluster also rejects growth as the ultimate answer to
distributive conflicts. Neoclassical growth theory is generally
based on the assumption that economic growth increases
social welfare and, thus, treats growth as a desirable macro-
economic goal. The underlying assumption is that if the whole
economy is growing, in the end, the whole society is better off,
and distributive conflicts will emerge to a much lesser extent.
Thus, we could conclude that growth is a primary solution for
reducing distributional conflicts. Yet, our neoclassical cluster
does not share this view.
Statements that are particularly typical for cluster 2 are
summarized in Box 3.
Altogether, 63 persons are characteristic for cluster 2,
which equals with about one third (32%) of all participants.
These persons are largely members of the German Economic
Association (VfS, about 80%), some of the also being member
of its section for environmental and resource economics
(AURÖ, about 20%). However, some representatives of this
cluster are also members of the ISEE (about 15%), whereas the
German ecological-economic associations can be neglected
regarding their shares in this cluster.
3.4. Key divides between the clusters of ‘ecological economics’
and ‘open-minded neoclassical environmental economics’
In order to identify the strongest differences, we selected
those statements that received rankings going in opposite
‘directions’(+, −) from both clusters, and of which at least one
ranking is equal to/ higher than +1, or equal to/lower than −1.
Furthermore, we set a minimum ranking ‘distance’between
the clusters of 1.5 (e.g., +1 for cluster 1 and −0.6 for cluster 2).
Based on these definitions, strongly opposed opinions
between the clusters appear to be those regarding intra-
generational justice, which is very strongly rejected as being
the precondition for intergenerational justice by the neoclassical
cluster, but is supported by the ecological-economic cluster. A
strong conceptual dissent also exists regarding the utilitarian
conception of human behavior (homo economicus), which is
rejected by the ecological-economics cluster and supported by
the neoclassical cluster. Finally,clear differences in opinionexist
with respect to many aspects of sustainability policy. Here, the
neoclassical cluster strongly denies that fundamental changes
Box 3
Distinct statements of cluster 2 ‘open-minded neoclassical
environmental economics’
Conceptions of justice and sustainability: Sustainability
cannot be defined as non-declining utility for a representative
individual over unlimited time. Intergenerational justice does
not presuppose intra-generational justice.
Sustainability policy: Sustainability does not require restric-
tions on material consumption. Sustainability is achievable
not only through fundamental changes of our economic
system. The utilization of the environment can be restricted
to a level that is sustainable by setting the ‘right’prices.
International specialization leads to long-lasting growth of
wealth worldwide.
Conception of science: Economic science should be objective.
Box 2
Distinct statements of cluster 1 ‘ecological economics’
Conceptions of justice and sustainability: An essential
conceptual element of sustainability is an integrated under-
standing of societal welfare (economic, ecological, social).
Substitution and valuation of nature: Natural capital can be
substituted by human-made capital only to a very limited
extent. The economy is dependent for its existence on the
interrelations in nature. The value of an intact environment
cannot, as an approximation, be expressed in monetary
terms.
Conception of human behavior: Questions of sustainability
cannot be answered on the basis of a concept of self-
interested human behavior.
Sustainability policy: Changing societal value systems is an
important element for a strategy of sustainability. Economic
growth as a goal can be questioned. Creating private
property rights over the environment cannot largely solve
the problem of overusing the environment.
Conception of science: Sustainability economics must deal
with the question of how to make decisions in an
intergenerational context. Economic science should not be
value-free.
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of our economic system and material consumption restrictions
are necessary for achieving sustainable development. On the
contrary, the ecological-economics cluster favors exactly these
approaches. Furthermore, the neoclassical cluster supports
international specialization as a way towards more, sustainable
welfare worldwide—an assumption deeply questioned by the
ecological-economic cluster. There is also a clear difference
between the clusters regarding their conceptions of science.
While the neoclassical cluster strongly demands an objective
science, the position of the ecological-economics cluster is
inclined towards a subjectivist methodology of science. The
statements with the strongest differences in opinion are
summarized in Box 4.
4. Opinions about the scientific divide and
perspectives of sustainability research
The study participants were also asked about their percep-
tions of and opinions on the scientific divide between
neoclassical environmental economics and ecological eco-
nomics as well as perspectives of sustainability research. A
clear majority of representatives of both clusters acknowledge
the existence of a scientific divide in sustainability related
economic research. Yet, the majority is somewhat larger for
the ‘ecological economics’cluster, with 83%, than for the
‘neoclassical economics’cluster, with 70%. There are also
differences between the clusters related to the perceived
effects of the scientific divide. Overall, the ‘open-minded
neoclassical economics’cluster sees the scientific divide
rather as a normal phenomenon, putting less emphasis on
its positive or negative consequences than the ‘ecological
economics’cluster does (see Fig. 1).
Whereas both scientific clusters largely agree that sustain-
ability is an important field of future economic research, still
about 70% of those representing the ‘ecological economics’
cluster and about 80% representing the ‘open-minded neo-
classical economics’cluster share the opinion that economics
has an important role in sustainability research (see Fig. 2).
Asked about future fields
6
of sustainability economics out of a
predefined set of alternatives, representatives of both clusters
considered environmental economics, development economics,
growth theory, and integration with environmental sciences
(natural sciences and engineering) to be most important. They
also emphasize the need for empirical and applied sustainability
research that is oriented towards policy advice. In addition,
representatives of the ‘ecological economics’cluster see social
economics, distribution theory, evolutionary economics, and
Box 4
Key divides between the clusters of ‘ecological economics’and
‘open-minded neoclassical environmental economics’
Conceptions of justice and sustainability: Intergenerational
justice presupposes intra-generational justice.
Conception of human behavior: Questions of sustainability
can be answered on the basis of a concept of self-interested
human behavior.
Sustainability policy: Sustainability requires restrictions on
material consumption. Sustainability is achievable only
through fundamental changes of our economic system.
International specialization leads to a long-lasting growth of
wealth worldwide.
Scientific conception: Economic science should be objective.
Fig. 1–Perceived existence and effects of a divide in
economic sustainability research.
Fig. 2–Perceived importance of economics in sustainability
research.
6
We use future fields as a general term for topics, sub- or mixed
disciplines, methods, and further aspects of sustainability research,
whichshouldbeemphasizedmorestronglyinfuturesustainability
related economic research.
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integration with other social sciences (e.g., psychology, sociol-
ogy) as being important as well, while representatives of the
‘open-minded neoclassical economics’cluster emphasize basic
theoretical and empirical research (see Fig. 3).
Since the results presented above are based on a given
selection of future fields, the participants had the opportunity
to add an unlimited number of further future fields. In this
open question, representatives of both clusters were in
agreement in mentioning institutional and innovation eco-
nomics, ecological economics, political economy, public
choice theory, and economic ethics. Representatives of the
‘ecological economics’cluster, making up the majority of
those answering this open question, added further disciplines,
methods and topics. Categorizing these very diverse future
fields reveals the following overriding issues:
- Methodological and analytical approaches for operationa-
lizing sustainability;
- Global and regional economic perspectives;
- Theories of collective learning, cooperation and networking;
- Gender studies, social and labor economic aspects;
- Integration with (political) philosophy, philosophy of
science, cultural sciences, communication science, critical
theory, social psychology;
- Theory of complex systems, plural economics, economic
variety; and
- Approaches for sustainability activities on the business
level.
5. Summary and conclusions
Our study shows that there is a clear divide within German
economists in sustainability research, largely along the lines
that are described in the literature. We do not find any
additional clusters either within or across the established
schools of thought. Thus, we have shown that there is in fact a
foundation in the perceptions of researchers for the paradig-
matic and institutional divide of ecological economics and
neoclassical environmental economics. However, we find
some overlap regarding the scientific associations in which
the clusters are embedded: researchers holding an ecological-
Fig. 3 –Future fields of sustainability research in economics, based on a given selection, multiple choice possible (percentages of
total discourse representatives).
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economic view can also be found in the German Economic
Association (that we assumed to be neoclassical) and some
people sharing a rather neoclassical-economic perspective
also enter the ISEE. In addition, the study participants perceive
the scientific divide in different ways: neoclassical environ-
mental economists see the divide primarily as a normal
phenomenon of scientific cluster; ecological economists tend
to put a strong emphasis on its negative, but also its positive
effects.
Both the neoclassical and ecological-economic cluster
show a relative maturity of paradigm evolution: There is a
broad spectrum of common opinions within them about their
concepts of sustainability and justice, their sustainability
policy recommendations, and their conceptions of science.
Whereas this result may be expected for neoclassical econom-
ics (a school of thought with a history of about more than a
century, taking the founding year of the American Economic
Association (1885) as a starting point), it is a remarkable sign of
maturation of a school of thought that started out only in the
1970s
7
as a scientific movement of those concerned about
environmental degradation.
Ecological economists in our sample group themselves
around the principle of strong sustainability. They share the
opinion that natural capital can ultimately not be substituted
by human-made capital, but that it is essential for the long-
term existence of the economy. The ecological-economics
cluster rejects mainstream policy solutions such as the goal of
growth and the policy instrument of property rights over the
environment. Instead, it appears to be strongly (almost
exclusively) oriented towards a number of value-related
issues (bio-physical approaches to valuation of nature, chan-
ging societal values as political strategy, rejection of the self-
interested image of human behavior, rejection of value-free
economics) and intergenerational justice. The fact that our
neoclassical cluster is indifferent about these explicitly value-
related issues indicates to us that both schools of thought
seem to continue to go in different directions with respect to
the inclusion of values. It seems to also signify a gap in the
mainstream that ecological economists can (continue to) fill
with much success, perhaps contributing to a broad paradigm
shift within economics dealing with sustainability (in the
sense of Kuhn, 1962).
In our sample, neoclassical economics appears to be ‘open-
minded’. Unlike some participants of the international work-
shop described in the Introduction, it generally disagrees with
the idea that growth is the primary answer to the challenges of
sustainability, which was still an accepted view by a large
number of environmental economists in the 1970s (e.g.,
Beckerman, 1972). Also, treating intergenerational problems
as non-declining utility of a representative individual is
rejected in favor of a rather more evolutionary concept
(‘preserving future development potentials’). Both views are
shared with the ecological-economics cluster—a surprising
finding to us.
Besides the orientation at development potentials, there is
an unexpectedly broad conceptual basis shared by both
schools of thought with respect to including economic, social
and ecological dimensions. Yet, how these dimensions are to
be valued against each other (especially weighting the
ecological dimension) remains an issue of dispute. Some
common ground exists also with respect to what is empirically
un-doable in sustainability research, namely the identifica-
tion of indispensable resources. However, this commonalty
does not necessarily mean that the clusters also draw the
same conclusion from it. Rather, it is most likely that the
ecological-economic cluster tends to conclude that, because of
this uncertainty, a large variety of natural resources should be
preserved (precautionary principle). Yet, the statement also
implies that the—typically ecological-economic—normative
setting that all people must be allowed to satisfy their basic
needs (Ekins and Max-Neef, 1992) does not lead to a certain set
of indispensable resources that must be protected in the long
run. In opposition to the ecological-economic view, the
neoclassical-economic cluster may tend to conclude that
resource use today does not have to be limited because once
the resources are scarce this will lead to technological
innovations finding other ways of satisfying human needs
(technological optimism).
Further common grounds and, thus, possible ‘bridges’
between the clusters are that they both consider economic
research to be important for sustainability, stressing the need
for interdisciplinary, empirical and applied research that is
oriented towards policy advice. The representatives also
largely agree about promising fields for joint future research
by emphasizing environmental economics, development
economics, growth theory, and the integration with environ-
mental sciences (natural sciences and engineering). Yet, the
research agenda of the ecological-economics cluster contain a
large number of additional topics related to social, distribu-
tional and evolutionary aspects of sustainable development, a
strong microeconomic focus, but also to spatial aspects,
systemic approaches and methods for operationalizing sus-
tainability. It also suggests being more open towards the social
sciences.
Yet, despite all these commonalities, strong dividing lines
between the groups remain. The consideration of intergenera-
tional questions does not imply for our neoclassical economics
group the inclusion of intra-generational questions of dis-
tribution in economic analysis; and to be open to a sustain-
ability concept of preserving development potentials for future
generations does not mean a general orientation away from
‘normative individualism’. Critique of the ‘system’by our
‘neoclassical economics’cluster is relatively modest compared
to that of the ‘ecological economics’cluster. Fundamental
changes of the economic system, material restrictions of
consumption, and a general move away from the international
division of labor are not acceptable for the neoclassical group.
Thus, for future developments of economic research in
sustainability, we can expect a lasting controversy between
ecological and neoclassical economists about the question of
how to achieve sustainable development. Another dividing
line that seems to be hard to overcome is the difference in
7
While thereare roots to ‘ecological economics’going back even to
the early romantics of the 18th century, it did not form a ‘school of
thought’before the works of Kenneth Boulding (1966),Nicholas
Georgescu-Roegen (1971),Herman Daly (1977) and others were
published. The International Society of Ecological Economics, in
fact, was only founded in the year 2000. See Røpke (2004) for an
overview on the history of modern ecological economics.
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conceptions of science: Economics has to be objective and
(possibly) value-free in the opinion of our neoclassical
economist sample, whereas our ecological economists share
the conception of postmodern science. All of these issues seem
to be potential obstacles for establishing dialogue aimed at
harmonization between the groups. Yet, the topics may at the
same time provide ground for a kind of ‘scientific competition’
concerned with finding explanations and solutions to societal
problems of sustainable development.
This paper looked at the opinions of German researchers
on sustainability and economics to get an empirically-based
understanding on if and how ‘schools of thought’—as they are
perceived in the literature—correspond to the subjective
beliefs of the people belonging to this ‘schools’. While we
found a great deal of correspondence in belonging and
believing, we also discovered some unexpected ‘open-mind-
edness’amongst neoclassical economists that could help
build bridges between both groups. This may be an artifact of
studying a sample of German researcher or due to our
sampling method of asking members of professional associa-
tions. Thus, using a broad-based international questionnaire
format may further enhance our understanding of the
‘scientific divide’between ecological economics and neoclas-
sical economics. We also believe that differences between
people often reveal much more in what they do rather than in
what they think. Therefore, looking into the applied concepts
of human behavior, methods of assessment of ecosystem
services, and sustainability policy advises given in different
countries, would probably also lead us to a deeper under-
standing of how the actors of both ‘schools of thought’relate.
But this, too, is left for future research.
Acknowledgements
The authors would like to thank Matthias Deutsch for his
literature evaluation, providing the basis for generating the
statements that are the heart of our survey. Many thanks also
to two anonymous reviewers who gave us very helpful
comments. This article is based on research supported by
the German Federal Ministry for Education and Research.
Appendix A.
Annex
List of all statements used in the questionnaire
(1) Sustainability is an important future field of economic
research.
(2) In relation to other disciplines, economics has an
important role in sustainability research.
(3) There is a scientific divide, with ecological economics
on one side and neoclassical economics on the other.
(4) Sustainability can be defined as non-declining utility of
a representative individual over infinite time.
(5) Sustainability means preserving development opportu-
nities for future generations.
(6) The stock and structure of non-substitutable natural
capital has to be maintained for future generations.
(7) Natural capital can be substituted by human-made
capital only to a very limited extent.
(8) The acceptability of accident-related risks should be
gauged with regard to the maximum possible damages
that they may incur on humans and nature.
(9) Changing societal value systems is an important
element for a strategy of sustainability.
(10) Sustainability requires restrictions on material
consumption.
(11) Intergenerational justice presupposes intra-genera-
tional justice.
(12) Sustainability economics must deal with the question of
how to make moral decisions in an intergenerational
context.
(13) Economists can make value judgments on issues of
intergenerational and intra-generational distribution.
(14) Efficiency and distribution should be analyzed sepa-
rately in a macroeconomic context.
(15) The basic conflict between efficiency and equitable
distribution can ultimately be solved only through
economic growth.
(16) Extending the sustainability concept to also include
social and economic dimensions does not dilute the
concept's normative power.
(17) It is a realistic scenario that humankind is going to
destroy its own basis for existence.
(18) A core problem of sustainability is population growth.
(19) The economy is dependent for its existence on the
interrelations in nature.
(20) The maintenance of nature has a value in itself, indepen-
dently of its value for humans.
(21) Efficiency leads to more sustainability.
(22) Technical innovation is the key factor for sustainable
development.
(23) Sustainability is achievable only through fundamental
changes of our economic system.
(24) Economic growth as a goal cannot be questioned, only
how it happens.
(25) To reduce governmental debt is an important goal for
economic sustainability.
(26) International specialization leads to a long-lasting
growth of wealth worldwide.
(27) The utilization of the environment can be restricted to a
level that is sustainable by setting the ‘right’prices.
(28) Creating private property rights over the environment
can largely solve the problem of overusing the
environment.
(29) Sustainability is a problem of long-term planning (e.g.,
of resource utilization).
(30) Uncertainties about the long-term effects of economic
activities can be incorporated into economic analyses
by means of probability estimations.
(31) It is possible to determine for an infinite time-horizon
which resources will be indispensable for humans.
(32) The value of an intact environment can, as an approx-
imation, be measured in monetary terms.
(33) The preferences of individuals have to be taken as given
in economic analysis.
(34) Questions of sustainability can be answered on the basis
of a concept of self-interested human behavior.
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(35) The political outreach of economic analyses is an
obstacle to generate sound economic theory.
(36) Economic science should be value-free.
(37) Economic science should be objective.
(38) An essential conceptual element of sustainability is an
integrated understanding of societal welfare (economic,
ecological, social).
(39) Sustainability research must overcome disciplinary
boundaries.
(40) Economic models should offer theoretically consistent,
partial views of reality that have to be combined with
findings of other scientific disciplines.
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