Patricia Villarrubia-Gómez, Sarah Elisabeth Cornell, Bethanie Carney Almroth, Morten Ryberg, Marcus Eriksen

Plastics are novel entities that have exceeded the planetary safe operating space due to extensive and resource-intensive production, uncontrolled environmental releases, and failure to control the chemicals within the materials. This paper examines evidence and discusses how plastics pollution affects Earth-system processes along the impact pathway from production, to release, to environmental fate and impacts of plastics and their additives. Multiple lines of evidence are necessary to capture the complex reality of these substances and attempts to quantify a singular boundary would be detrimental to the global governance of plastics. We demonstrate causal links between plastics and other major environmental problems at the global scale, exacerbating the consequences of breaching other planetary boundaries, especially climate change and biodiversity loss. We propose ways to translate these assessments into control variables for the globally and biophysically defined planetary boundaries framework that can be utilized to tackle plastics pollution. Efforts should be oriented towards further developing and monitoring a set of control variables that describe the actual state of the system along the impact pathway. We call for experts and policymakers to take urgent action, considering plastics pollution not only as a waste management problem but as an integrative part of climate change, biodiversity and natural resource use policy.