Our current linear way of producing plastics is widely regarded as unsustainable. However, quantifying absolute sustainability is actually an open problem. In this presentation, we will therefore explore the current state of knowledge regarding the sustainability of plastics. For this purpose, we employ life-cycle assessment and the concept of planetary boundaries to assess whether plastics transgress the safe-operating space. First, we will analyze the current linear fossil-based paradigm of plastics production. Next, we will study options for developing a circular plastics industry. Circular carbon flows can be established by employing biomass, CO2, and waste recycling.
The analysis shows that recycling is the key technology to reducing environmental impacts from the plastic life-cycle. Even though recycling alone will not be able to close the carbon cycle, it can minimize the amounts of plastics from biomass and CO2. Thereby, the resource demands can be reduced. The resulting plastics industry is expected to operate at cost comparable to the linear fossil industry. We will explore how the plastics industry could stay within the planetary boundaries and discuss promising targets for recycling.