31. He is the originator of the " ecological footprint " concept and co-developer of the method. 32. A big challenge for plastics engineers is the reduction of the ecological footprints of their products. 33. "EcoFootprinting " provides a way to measure your total use of productive land, or'ecological footprint '. 34. Cities, due to population concentration, have large ecological footprints and have become ground zero for footprint reduction. 35. The study, WWF's fifth since 1998, examined the " ecological footprint " of the planet's entire population. 36. Pulp made from wheat and flax straw has half the ecological footprint of pulp made from forests. 37. The Gabrielinos made sure to minimize their ecological footprint as much as possible to follow their beliefs. 38. Global Footprint Network calculates the global ecological footprint from UN and other data for over 200 nations. 39. Since 2006, a first set of ecological footprint standards exist that detail both communication and calculation procedures. 40. The ecological footprint , championed by the progress:
