about fourty percent of our energy.

And with our emissions threatening to permanently change our climate,

we need more efficient,

better, greener cities.

We can start by being smart with what we have:

passive solar buildings, public transit, private pedal power, high-density living and tele-working.

But our food production is still a long way from most of the people who live in the cities,

built on the best arable land. Vertical Farming could turn this on its head, or at

least its side. It would bring together a host of

emerging technologies by putting food production on the buildings we live and

work in.

To reduce land use,

cool our urban heat sinks,

and drastically reduce food transport costs.

Modern agriculture uses seventy percent of the world's available freshwater. But

Vertical Farms

could be fitted with 'nano-films' that boost condensation. And 'nano-membranes' would filter and clean recycled

water. Better water quality - less waste.

Crop effectiveness would be boosted by

genetic engineering to select the best

genetic variance for the environment.

Fiber optics

might provide light with incredible energy efficiency.

One square block farm thirty stories high, could

yield as much food

as ten square kilometers outdoors.

There are of course

hurdles. The crops best suited to Vertical Farming may require us to adjust our diets.

But would farmers and agribusiness take this lying down?

Or is it simply that our dollars are best spent on smart,

simple, and practical improvements to

existing infrastructure and technology.