Ms Brachlianoff said: "It sounds unbelievable but by 2050 it’s estimated that 70% of the world’s population will live in cities.
"That compares with just over 50% now and has huge implications for society and for our core business – how we preserve scarce raw materials, water, energy and waste.
"We see a future that can go one of two ways – resource efficient collaborative consumption based on a circular economy or a resource hungry urban sprawl."
Dr Savvas Verdis, Senior Research Fellow for LSE Cities at the London School of Economics, added: “We know from studying cities across Europe that the best-performing cities use a combination of infrastructure investment and innovative policies to encourage sustainable lifestyles.