There are a lot of people in the world, over 7.5 billion these days, and that number will continue to climb over the coming decades. According to UN statistics, in 2018 53% of the world's population live in urban centers, this number will rise to 60% by 2030. Urbanization, overall has been fantastic in helping to improve the quality of life of the world's population. Greater density means that resources can be utilized to greater effect, meaning that per capita environmental impacts are generally lower for urbanites than their sub-urban and rural counter parts. While many modern cities are working hard to further reduce their per capita environmental impact there is one inescapable fact, when a city is built or expands it is often displacing arable land that could either remain more wild or at least used as farmland. As humans continue to urbanize we should consider the possibility of creating cities in places that cannot be used as farmland.
According to the United Nations over 17% of the world's land mass is either desert or semi desert (hyper arad and arad), land that historically has made very little sense for large human populations to gather. What would it look like if humans were to begin moving their population into these desert regions by building sustainable cities of the future?
Before we look at the technologies and potential urban planning solutions that could be used to make these proposed desert cities sustainable, let us first look into the math of estimating how big these new urban centers would need to be. Our first assumption is that these cities are unlikely to get their food from traditional farmlands located within the bounds of the city (this would still allow for either food imports, vertical farming, a mix of the previous two, or something entirely unimagined by this author). The next assumption has to do with how many people will relocate to these new urban centers, the lower bound is obviously zero, for any number of reasons people just don't want to move to a manufactured urban center, the upper bound is almost 100% of humans, where authoritarian regimes have forced all people to live in these new cities, and only a few hold outs remain outside city limits. The last variable (for the basic calculation) is the population density of our new cities.
Population densities can have a tremendous impact on how efficiently resources can be shared by residents of a city, but it also can impact your quality of life. While it might be super efficient to have 50 people share a single dorm style bathroom many would consider that a less than desireable compremise on quality of life. Kowloon Walled City is considered one of the most densely
populated urban environments in human history, at its height Kowloon WalledCity had an effective population density of 1.2 million people per square kilometer
(I say effective population density as the city only covered 0.026 square
kilometers) To put things into perspective, if all humans
lived at the density of the Walled City, you could fit every human being into an
urban environment just about the size of Delaware (this sounds like it could have a decent chance
of being rather unpleasant). On the other end of the spectrum we have the city
of Anchorage Alaska, with a population density of about 60 people per square
kilometer, at the population density of Anchorage, we would need to create a
city that covered 128.3 million square kilometers (the entire Earth only has
510 million square kilometers of land) A
sweet spot might be something like the population density of a place like Boston
Massachusetts, with a density of 5100 people per square kilometer, you would only
need 1.5 million square kilometers of city to house all of humanity. At this time you might be questioning the
statistic used for the population density of Boston, as you have likely seen
photos of Boston, with its collection of sky-scrapers and ability to play act
at being a big city. The reason for your
confusion stems from the fact that much of Boston is devoted to things like
office space for people who come into the city from other communities to
work. North of Boston in Cambridge the
population density is much higher at 6300 per square kilometer, with Somerville
taking the cake with an average density of 7100 residents per square kilometer,
all without resorting to large tracts of skyscrapers (this may change over
time).
For sake of argument we will assume
our desert cities will strive for a population density like Cambridge,
Massachusetts. We will now assume that
roughly 20% of the world’s population could be convinced to move into these new
urban centers that means we are going to be making cities for 1.5 billion
people, that is more than the population of either India or China. These new cities will require roughly 245
thousand square kilometers (95 thousand sq miles or just shy of the area of the
state of Oregon) of land to be converted into cities. Now this amount of desert being converted
into cities seems like a lot and in human terms it is, for comparison, the
Sahara Desert is 9.2 million square kilometers (3.5 million square miles). That means that our new cities would cover
less than 3 percent of the entire Sahara, let alone the other large deserts of
the planet. It also means that if we
decided to move all humans into the Sahara, we could do so with land left over*.
Thanks for reading part 1 of the
desert development outline, Part 2 will
focus on some of the technologies and policies that might be useful to ensuring
that people actually want to live in these new Desert Cities
*7.7 billion humans / 6300
humans/sq km = 1.2222 million sq kilometers
1.2 million sq kilometers/9.2
million sq kilometers of sahara *100%= 13.3 % of the Sahara Desert
Reduced per capita environmental impacts are beneficial, but we can do better.
In most instances when a city needs to expand, the city willwill do so by acquiring neighboring land and converting it into a part of the city, by building more dense structures. This is natural and not unreasonable, unfortunately there are times where that expansion is done at the cost more ecologically sensitive regions
As humans continue to urbanize many urban planners and architects are working hard to make their cities as sustainable as possible for future generations
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