Planet Earth is a vast place, with humans scattered all over it.
But how we're distributed is far from even. About half of the planet's 7.5
billion people live in just seven countries. China tops the list with over 1.4
billion people, while its neighbor India is catching up fast at 1.3 billion.
Though far below the billion mark, the United States comes in third, with about
325 million people. Indonesia, Brazil, Pakistan and Nigeria round out the top
seven.
Dividing the world up by continents can give a sense of where the world's
population is clustered. North and South America combined have about a billion
people. Africa has 1.3 billion, and Europe is at 742 million. And then there's
Asia, with 4 1/2 billion people. That's more than half of the humans on Earth.
How many more people will there be in the next hundred years? The United Nations
estimated in a report released Wednesday that by 2100, the human population will
actually stop growing.
By then, the U.N. predicts that more people will live in cities, make more
money, have more to eat, get better health care and have fewer kids.
There will probably be about another half-billion people in Asia and 3 billion
more in Africa, which is currently the continent with the youngest average age.
If the U.N. estimate holds up, there will eventually be 11.2 billion people
living on Planet Earth, about 50 percent more than the current 7.5 billion. And
80 percent of future earthlings will live on just two continents — Asia and
Africa.
Correction
June 23, 2017
A previous version of this story incorrectly said Africa and
Europe have a combined population of about 1 billion.
In fact, the continents have a total of about 2 billion people.
IF climate change and population growth progress at their current pace, in
roughly 50 years farming as we know it will no longer exist. This means that the
majority of people could soon be without enough food or water. But there is a
solution that is surprisingly within reach: Move most farming into cities, and
grow crops in tall, specially constructed buildings. It’s called vertical
farming.
The floods and droughts that have come with climate change are wreaking havoc on
traditional farmland. Three recent floods (in 1993, 2007 and 2008) cost the
United States billions of dollars in lost crops, with even more devastating
losses in topsoil. Changes in rain patterns and temperature could diminish
India’s agricultural output by 30 percent by the end of the century.
What’s more, population increases will soon cause our farmers to run out of
land. The amount of arable land per person decreased from about an acre in 1970
to roughly half an acre in 2000 and is projected to decline to about a third of
an acre by 2050, according to the United Nations. With billions more people on
the way, before we know it the traditional soil-based farming model developed
over the last 12,000 years will no longer be a sustainable option.
Irrigation now claims some 70 percent of the fresh water that we use. After
applying this water to crops, the excess agricultural runoff, contaminated with
silt, pesticides, herbicides and fertilizers, is unfit for reuse. The developed
world must find new agricultural approaches before the world’s hungriest come
knocking on its door for a glass of clean water and a plate of disease-free rice
and beans.
Imagine a farm right in the middle of a major city. Food production would take
advantage of hydroponic and aeroponic technologies. Both methods are soil-free.
Hydroponics allows us to grow plants in a water-and-nutrient solution, while
aeroponics grows them in a nutrient-laden mist. These methods use far less water
than conventional cultivation techniques, in some cases as much as 90 percent
less.
Now apply the vertical farm concept to countries that are water-challenged — the
Middle East readily comes to mind — and suddenly things look less hopeless. For
this reason the world’s very first vertical farm may be established there,
although the idea has garnered considerable interest from architects and
governments all over the world.
Vertical farms are now feasible, in large part because of a robust global
greenhouse initiative that has enjoyed considerable commercial success over the
last 10 years. (Disclosure: I’ve started a business to build vertical farms.)
There is a rising consumer demand for locally grown vegetables and fruits, as
well as intense urban-farming activity in cities throughout the United States.
Vertical farms would not only revolutionize and improve urban life but also
revitalize land that was damaged by traditional farming. For every indoor acre
farmed, some 10 to 20 outdoor acres of farmland could be allowed to return to
their original ecological state (mostly hardwood forest). Abandoned farms do
this free of charge, with no human help required.
A vertical farm would behave like a functional ecosystem, in which waste was
recycled and the water used in hydroponics and aeroponics was recaptured by
dehumidification and used over and over again. The technologies needed to create
a vertical farm are currently being used in controlled-environment agriculture
facilities but have not been integrated into a seamless source of food
production in urban high-rise buildings.
Such buildings, by the way, are not the only structures that could house
vertical farms. Farms of various dimensions and crop yields could be built into
a variety of urban settings — from schools, restaurants and hospitals to the
upper floors of apartment complexes. By supplying a continuous quantity of fresh
vegetables and fruits to city dwellers, these farms would help combat health
problems, like Type II diabetes and obesity, that arise in part from the lack of
quality produce in our diet.
The list of benefits is long. Vertical farms would produce crops year-round that
contain no agro-chemicals. Fish and poultry could also be raised indoors. The
farms would greatly reduce fossil-fuel use and greenhouse-gas emissions, since
they would eliminate the need for heavy farm machinery and trucks that deliver
food from farm to fork. (Wouldn’t it be great if everything on your plate came
from around the corner, rather than from hundreds to thousands of miles away?)
Vertical farming could finally put an end to agricultural runoff, a major source
of water pollution. Crops would never again be destroyed by floods or droughts.
New employment opportunities for vertical farm managers and workers would
abound, and abandoned city properties would become productive once again.
Vertical farms would also make cities more pleasant places to live. The
structures themselves would be things of beauty and grace. In order to allow
plants to capture passive sunlight, walls and ceilings would be completely
transparent. So from a distance, it would look as if there were gardens
suspended in space.
City dwellers would also be able to breathe easier — quite literally. Vertical
farms would bring a great concentration of plants into cities. These plants
would absorb carbon dioxide produced by automobile emissions and give off oxygen
in return. So imagine you wanted to build the first vertical farm and put it in
New York City. What would it take? We have the technology — now we need money,
political will and, of course, proof that this concept can work. That’s why a
prototype would be a good place to start. I estimate that constructing a
five-story farm, taking up one-eighth of a square city block, would cost $20
million to $30 million. Part of the financing should come from the city
government, as a vertical farm would go a long way toward achieving Mayor
Michael Bloomberg’s goal of a green New York City by 2030. Manhattan Borough
President Scott Stringer has already expressed interest in having a vertical
farm in the city. City officials should be interested. If a farm is located
where the public can easily visit it, the iconic building could generate
significant tourist dollars, on top of revenue from the sales of its produce.
But most of the financing should come from private sources, including groups
controlling venture-capital funds. The real money would flow once entrepreneurs
and clean-tech investors realize how much profit there is to be made in urban
farming. Imagine a farm in which crop production is not limited by seasons or
adverse weather events. Sales could be made in advance because crop-production
levels could be guaranteed, thanks to the predictable nature of indoor
agriculture. An actual indoor farm developed at Cornell University growing
hydroponic lettuce was able to produce as many as 68 heads per square foot per
year. At a retail price in New York of up to $2.50 a head for hydroponic
lettuce, you can easily do the math and project profitability for other similar
crops.
When people ask me why the world still does not have a single vertical farm, I
just raise my eyebrows and shrug my shoulders. Perhaps people just need to see
proof that farms can grow several stories high. As soon as the first city takes
that leap of faith, the world’s first vertical farm could be less than a year
away from coming to the aid of a hungry, thirsty world. Not a moment too soon.
Dickson D. Despommier,
a professor of public health at Columbia University,
