Hemp Fibre Life Cycle Carbon Footprint
topic
LCA studies of hemp fibre (ISO 14040/14044, cradle-to-gate) report GWP of 0.5–1.5 kg CO₂e/kg scoured fibre (Netherlands rain-fed cultivation) versus 5.5–8.0 kg CO₂e/kg conventional cotton and 3.5–5.5 kg CO₂e/kg polyester. Carbon sequestration during hemp crop growth is 1.63 kg CO₂/kg dry biomass, with 25–30% of total plant biomass being harvested bast fibre. Allocation of carbon credits between bast fibre (25%), hurds (65%), and seed (10%) co-products significantly affects system-level GWP — fibre GWP ranges from −0.5 to +1.5 kg CO₂e/kg depending on co-product allocation method (mass, economic, or system expansion). Processing (retting, decortication, spinning) adds 0.8–2.5 kg CO₂e/kg, mainly from energy consumption of wet spinning (0.5–1.2 kWh/kg yarn). Hemp-cotton blend (55/45) T-shirt total carbon footprint is 2.5–3.5 kg CO₂e versus 4.0–5.5 kg CO₂e for 100% cotton equivalent. System expansion LCA crediting hurds and seed oil co-products can produce a net-negative cradle-to-gate hemp fibre GWP of −0.3 to −1.2 kg CO₂e/kg.
Role
Quantified hemp LCA carbon data provides the scientific basis for brand sustainability claims, enabling science-based target alignment and providing procurement teams with credible environmental benchmarks for substituting cotton with hemp in fibre blending strategies.