This article explores the emergence of waste valorization innovations to investigate how they interact with incumbent waste management systems and what roles markets play in the process. We build upon innovation ecosystems as an analytical framework and investigate empirically three cases distributed across the waste hierarchy pyramid: (i) upcycling of discarded fishing gear; (ii) reusing constructions and recovering demolition waste; and (iii) establishing a biomass‐based district heating facility. Our cases indicate that waste valorization initiatives are deeply entangled in incumbent waste management systems and that markets alone appear to be insufficient to drive innovations in waste valorization. Our analysis also points to a relationship between the position of waste innovation in the waste hierarchy and the presence and effectiveness of markets. Markets function better when resources already have some economic value, which is what waste valorization processes seek to obtain. When the environmental value is higher than the economic value, other mechanisms are needed to enable innovations, markets, and sustainability transitions. Support from the public sector in various capacities, from international regulation to demand shaping, seems to be essential for circular economy transitions. Understanding issues such as how waste innovations reach the market and how markets for waste resources function is imperative for circular economy transitions.

Meaningful engagement between scientists and stakeholders has been extensively promoted as a tool for increasing public participation in science, as well as for increasing the relevance and impact of scientific research. Yet, co-production of knowledge entails practical challenges, since participants with diverse worldviews, expertise and interests are expected to collaborate. These obstacles have not received enough attention, as current debate has focused more on the merits and principles of this approach. We address this gap by reflecting upon our experiences with both practical and methodological challenges stemming from research projects based on co-production of knowledge, thereby exposing what we see as common but under-discussed obstacles, as well as guidance for tackling them. We highlight the role of social scientists in the process not merely as facilitators but also as agents that promote critical reflection and safeguard the salience, credibility, and legitimacy of both the process and its outputs.

The problem of marine litter represents a significant global challenge and illustrates the harmful consequences of an economic model that is based on disposability. The seafood sector is not only among the culprits, but is also among the most affected by this threat to the marine environment. Earlier research has pointed to fishing gear take‐back schemes as a measure to mitigate the problem, and policymakers have embraced the idea. The Norwegian scheme for beverage containers has been hailed as a benchmark for the application of Extended Producer Responsibility. Through the lens of business ecosystems, we draw parallels between the existing take‐back scheme for beverage containers and the latent system for fishing gear to answer the question: “What would it take to establish a take‐back scheme for fishing gear? ” We elaborate upon four factors that are well established for beverage container take‐back schemes, but lacking or unclear in the case of fishing gear: (i) politico‐institutional support, (ii) the system's value proposition, (iii) the system integrator, and (iv) operational factors (i.e., a network of collection points and procedures, and material variety and complexity). Our findings highlight that when innovations are not based on the usual market mechanisms, unconventional conceptualizations of value itself and how value is mapped and distributed are required. Meaningful engagement of the private sector depends upon either explicit articulation of value capture or policy instruments to enforce responsibility; both are currently either unclear or lacking in the context of fishing gear.