4:30
This tree is rising nearly 30 storeys. It's one of almost 800 being planted to create a vertical forest in Milan. This number of living trees would normally fill two hectares of woodland, but here they occupy one tenth of that area. Greening the walls and roofs of our buildings could create a rich and extensive habitat, if we wanted it to do so. There is one city where that idea is being applied on a major scale - Singapore. Two million trees have been planted here in the last 45 years.
This city is now richer in species than any other in the world. And this practice extends to all parts of the city. The waterways have been cleaned up and smooth-coated otters are coming back. But perhaps the most spectacular example of city greening is this grove of "supertrees". These 150ft-high metal structures are now full of life.
Creepers have been planted to grow over the outermost branches. This is a new urban world that we have now designed and built with others in mind. Create the space and the animals will come. Is this a vision of our cities of the future?
It could be possible to see wildlife thriving within our cities, across the planet. We, after all, are the architects of the urban world. Now, over half of us live in an urban environment. My home too is here, in this city of London. Looking down on this great metropolis, the ingenuity with which we continue to reshape the surface of our planet is very striking. But it's also sobering. It reminds me of just how easy it is for us to lose our connection with the natural world. Yet it's on this connection that the future of both humanity and the natural world will depend.
It's surely our responsibility to do everything within our power to create a planet that provides a home not just for us but for all life on Earth.
