Up, Down & Back Again: Value Judgements in Polymer Recycling

The intersection between climate change, energy transitions, and the circular economy highlight the opportunities and contestations between different efforts to mitigate the complex environmental challenges we face. The energy we use to extract, manufacture, remanufacture, and dispose of our material world is a major contributor to diverse climate impacts, an issue which is compounded by linear economic models that necessitate eternal extraction. Yet many of the materials we depend upon are exceptionally efficient at enabling functions that facilitate social, economic, and environmental sustainability. This dichotomy is arguably most acutely debated in the world of polymers and plastics. While recycling has long been touted as a solution space for plastic sustainability, a plethora of chemists, biologists, and engineers have more recently expanded global research in this direction. The resultant proliferation of terms like ‘up-’ or ‘down-’ or ‘re-’cycling that frame these opportunities are often poorly defined as value propositions. The danger lies in directions acting as a barrier to circularity, or even greenwashing transformations. Herein, we explore the value judgements and verifications of this directionality, investigate how we can better define these value judgements from a systems sustainability perspective, and evaluate different proposed approaches and their barriers across different supply chains and sectors.