Sustainability footprints of a renewable carbon transition for the petrochemical sector within planetary boundaries

TLDR

The petrochemical sector is a key player in low‑carbon transition technologies yet remains a major source of greenhouse gas emissions, and while momentum grows to replace fossil feedstocks with biomass, captured CO₂, and recycled resources, the broader environmental implications of these renewable carbon solutions remain unclear. The study aims to evaluate the overall sustainability of renewable carbon pathways by assessing their life‑cycle environmental footprints against the nine planetary boundaries. This assessment was performed by quantifying the life‑cycle environmental footprints of the pathways using the nine planetary boundaries framework. The analysis revealed that although renewable carbon pathways could reduce CO₂ emissions by 25–100%, the scenario with the lowest carbon footprint could exceed the biodiversity boundary by at least 30%, highlighting the danger of neglecting other planetary limits and suggesting new approaches for measuring decarbonization impacts in hard‑to‑abate sectors.

Abstract

The petrochemical sector will play a crucial role in developing low-carbon transition technologies, but the industry also contributes a significant proportion of greenhouse gas emissions. Momentum is building to help reduce the carbon footprint of this hard-to-abate sector, particularly through replacing fossil carbon feedstocks with carbon from biomass, captured CO2, and other recycled resources, but the broader implications of these so-called "solutions" remain unclear. Here, we assess the overall sustainability of such "renewable carbon pathways" by quantifying their life-cycle environmental footprints with respect to the previously defined nine planetary boundaries. We show that although a shift toward renewable carbon pathways could indeed reduce CO2 emissions by 25% to over 100%, the scenario with the lowest carbon footprint could exceed the biodiversity planetary boundary by at least 30%. Our work highlights the potential pitfalls of overlooking global environmental guardrails beyond greenhouse gas emissions reduction and identifies new avenues for quantifying the environmental footprint of decarbonization solutions for hard-to-abate sectors.