we're going to need a lot more farms

to feed the planet.

Yet, in a lot of places,

farming is almost impossible.

And much of the land

we can use for farming is disappearing.

With so many farms on land,

could we build farms vertically to save space?

Maybe it's time to grow ... up?

The United States has 10 percent

of the world's farmland.

But between the years 1992 and 2012,

over 12 million hectares (31 million acres)

of it was gobbled up due to development.

That's 70 hectares (175 acres) per hour.

As populations grow,

this is happening in other countries

around the world too.

So where can we grow food?

People have built farms all over our planet,

in the most unlikely places.

We've grown food in arid deserts

and on the sides of mountains,

and used greenhouses

to extend growing seasons.

But what about in a plantscraper?

A Swedish company called Plantagon

is working on one right now.

The $40 million World Food Building,

in Sweden, is set to open in 2020.

The company calls this process

So why should we farm vertically?

Well, we'd save a lot of space

and water.

In fact, vertical farming

saves 80-95% of the water

used in traditional outdoor farming,

by using computer controlled

mist and slow drip systems.

Vertical farming also means

we wouldn't need

expensive combines and tractors.

Cities would have fresher veggies,

and we wouldn't need to send trucks

great distances to transport food.

This would cut pollution too.

So how, exactly,

could we build a vertical farm?

Using the power of AI,

companies such as Belgium's

Urban Crop Solutions

are creating climate-controlled

vertical farms up to 24 levels high.

Farmers can grow anywhere

from 75,000 to 91.5 million crops

per year indoors.

The company also sells

indoor vertical farming kits

for 12 m (40 ft) shipping containers.

These kits offer four to six levels,

which can grow up to 54,000 crops per year.

With the ability to control the lighting,

moisture levels and nutrients

for each type of crop by using computers,

plants grow much faster in a vertical farm.

Plus, vertical farms don't require pesticides,

since they are contained indoors

and are high up off the ground

where many insects thrive

The majority of the crops grown

in vertical farms include

leafy green vegetables like

kale,

bok choi,

watercress,

arugula,

lettuce,

mizuna,

mustard greens,

collard greens,

basil,

mint,

chard

and chives.

That's almost everything you'd need

for a power smoothie.

Companies have started building vertical farms

in existing urban spaces,

such as abandoned warehouses and factories.

The vertical farms can turn cities'

excess heat and waste

into vital assets for local food production.

In China, entire districts are devoted

to agriculture and vertical farming.

With a rapidly growing population,

less and less land has become available,

and pollution is a big problem

for traditional farms.

In this case, growing vertically

has become a necessity.

Vertical farms have proven to be invaluable

after natural disasters,

such as the destruction

of the nuclear power plant

at Fukushima in Japan in 2011.

Since land near the reactor

was not safe for growing crops,

consumers were happy

to have their lettuce grown indoors.

Five years later,

there were more than

190 vertical farms in Japan.

One company says it grows

21,000 heads of lettuce per day.

That's a lot of salad!

Many countries in the Middle East

import almost 80% of their food

due to their arid climate and landscape.

Vertical farms could drastically

improve this situation,

and would also create more jobs in the area.

Tech companies like Google,

Amazon and Asia-Pacific

are already investing in vertical farming

and automated agriculture.

Soon we'll start seeing vertical farms

in many more urban areas.

These will help to bring communities together

and provide safe access to nutritious food.

But in order for vertical farms to succeed,

they will need the backing of consumers.

Some people argue that this kind of farm

is too unnatural or expensive.

While others like the idea

of fresh food produced closer to home.

What do you think?

Let us know in the comments below.

In the near future,

we may need to make vertical farming

an even bigger priority,

especially if we run out of oil.