On Sunday, December 16, 2018 at 10:37:24 AM UTC-6, a425couple wrote:
On 12/16/2018 3:53 AM, Mark Earnest wrote:
...we are going to have to build skyscrapers to the sky to hold everyone and we

are going to have to ship a lot of people to exoplanets among the stars...


In Robert Silverberg's "The World Inside" he addresses that thought.

https://en.wikipedia.org/wiki/The_World_Inside
The novel is set on Earth in the year 2381, when the population of the
planet has reached 75 billion people.[4] Population growth has
skyrocketed due to a quasi-religious belief in human reproduction as the
highest possible good. Most of the action occurs in a massive
three-kilometer-high city tower called Urban Monad 116.

Plot summary
War, starvation, crime and birth control have been eliminated. Life is
now totally fulfilled and sustained within Urban Monads (Urbmons),
mammoth thousand-floor skyscrapers arranged in "constellations", where
the shadow of one building does not fall upon another. An Urbmon is
divided into 25 self-contained "cities" of 40 floors each, in ascending
order of status, with administrators occupying the highest level. Each
building can hold approximately 800,000 people, with excess population
totalling three billion a year transferred to new Urbmons, which are
continually under construction.

The Urbmon population is supported by the conversion of all of the
Earth's habitable land area not taken up by Urbmons to agriculture. The
theoretical limit of the population supported by this arrangement is
estimated to be 200 billion. The farmers live a very different
lifestyle, with strict birth control. Farmers trade their produce for
technology and the two societies rarely have direct contact; even their
languages are mutually unintelligible

Looks like somebody else thought of this even before I did...