Cutting carbon in pharmaceutical supply chains may depend less on how much a process emits – and more on where it sits in the network. A new study shows that structurally central players, such as logistics hubs and contract manufacturers, can disproportionately shape a product’s total carbon footprint, even when their own emissions are relatively modest.

The researchers combined life cycle assessment (LCA) with social network analysis (SNA) to map emissions across entire supply chains for three representative drugs, including polymyxin B and acarbose. They introduced a “responsibility contribution index” (RCI), which ranks supply chain nodes by both emission intensity and structural influence – capturing not just how polluting a node is, but how much it amplifies emissions across the network.

The results reveal a consistent pattern: carbon is highly concentrated along a handful of “backbone” pathways. In one case, a single cold-chain logistics node – despite low direct emissions – controlled most transport routes and ranked among the highest-impact intervention points. Meanwhile, high-emission processes with limited connectivity proved less influential at the system level.

By shifting focus from individual hotspots to network dynamics, the framework identifies more effective decarbonization strategies – targeting nodes that combine high emissions with strong control over flows. The approach offers practical guidance for pharma companies navigating tightening sustainability regulations, and suggests that smarter, network-aware interventions could deliver outsized carbon reductions across complex global supply chains.