The planetary boundaries (PBs) define ecological limits that are critical to preserve the stability of the Earth. Six of them have already been exceeded, which calls for urgent action to optimize industrial systems capable of operating within the safe operating space that they define for humanity. Here we discuss the challenges and opportunities of including PBs in a range of application domains in Process Systems Engineering, focusing on chemicals and fuels production and the use of mathematical programming coupled with life cycle assessment to support sustainable decision-making.