Following this initial article, two contributions by Bartelmus (2010) and van den Bergh (2010), as well as a reply by Baumgärtner and Quaas (2010b), started the conversation. Bartelmus (2010) argues for the monetarization of ecosystem services in integrated accounting systems. Monetarization is proposed since “only monetary valuation provides the measuring rod for comparing the significance of environmental services with that of economic activity” (p. 2054). Sustainability economics has, for Bartelmus (2010), the potential to bridge normative (sustainability) and positivist (economic)3 perspectives