He told the eFig conference in Swindon: "where's the logic that tells us you can have infinite growth on a finite planet. Exponential growth ends up in collapse."
Laurence, founder of Biotecture, added: "We have to grow food in and on buildings; it's not a nice idea, it has to be done because we don't have the energy to fly food from Kenya or South America on a whim because we fancy something on a supermarket shelf."
He added: "Average food miles for every single item is 1,200 miles. That's a heck of a cost and it happens because of the cheap cost of oil. Yet we have barely scratched the surface of ecosystem services, such as green walls and roofs and hydroponics."
"We need a global war footing on priority. When Pearl Harbour was bombed within four days the entire USA automative industry had been instructed to stop and switch to the war effort. We need that kind of urgency now. We won't get it but we need to do as much as we can to promote ecosystem services."