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The Future is Vast: Longtermism’s perspective on humanity’s past, present, and future

1.5 million years remaining: If Homo sapiens survives as long as Homo erectusHow long has Homo Erectus existed? Homo erectus is an extinct specie

1.5 million years remaining: If Homo sapiens survives as long as Homo erectus

How long has Homo Erectus existed? 

Homo erectus is an extinct species of archaic humans. It is  among the first recognizable members of the genus Homo. It was also the first human ancestor to spread throughout Eurasia,

Homo erectus survived for at least 1.7 million years. The oldest fossils regarded as Homo Erectus are the Dmanisi specimens from present-day Georgia, dated to 1.8 million years ago (Lordkipanidze et al, 2006). The most recent fossils are from present-day Indonesia, and have been dated to 0.1 million years ago (Yokohama et al., 2008).

How large was humanity’s future if we survived as long as Homo erectus?

If we – Homo sapiens – survive as long as Homo erectus we would have 1.5 million years left. Our future would be almost twice as large as shown in the chart in the main text. 

Almost 190 trillion children would be born into this world.

This is the calculation:

  • 1,500,000 years
  • 11,000,000,000 people
  • And the average person lives for 88 years

(1,500,000 years / 88 years per person) * 11,000,000,000 people = 

187,500,000,000,000 people = 

187.5 trillion people would be born in the next 1.5 million years

[Alternatively you could see this by considering that 1,500,000 years is 1.875-times longer than 800,000 years.]

1 billion years: If Homo sapiens survives as long as the earth is habitable

How long will Earth remain habitable? How long will our sun exist?

Astrophysicist Jillian Scudder, Anders Sandberg, and Toby Ord suggest that our planet will remain habitable for roughly a billion years.

Based on the scenario above this would be a future in which 125 quadrillion children will be born.

This is the calculation:

  • 1,000,000,000 years
    • 1,000,000,000 years is 1250-times longer than 800,000 years
  • 11,000,000,000 people
  • And the average person lives for 88 years

(1,000,000,000 years / 88 years per person) * 11,000,000,000 people =
(1,000,000,000 / 88) * 11,000,000,000 = 125,000,000,000,000,000 people = 125 quadrillion people would be born in this scenario in the next billion years.

A quadrillion is a one followed by 15 zeros (1,000,000,000,000,000).

125 quadrillion is 125 thousand trillion people (According to the short scale).

5 billion years – as long as the sun exists

If humanity survived for as long as the sun exists, 5 billion years.

  • 5,000,000,000 years
    • 5,000,000,000 years is 6,250-times longer than 800,000 years
  • 11,000,000,000 people
  • And the average person lives for 88 years

(5,000,000,000 years / 88 years per person) * 11,000,000,000 people =
625,000,000,000,000,000 people = 

625 quadrillion people would be born in this scenario in the next 5 billion years.

625 quadrillion is 625 thousand trillion people.

How to imagine 625 quadrillion births?

625 quadrillion relative to 100 trillion

Over the next 5 billion years: 625 quadrillion = 625,000,000,000,000,000

Over the next 800,000 years: 100 trillion = 100,000,000,000,000

625,000,000,000,000,000 / 100,000,000,000,000 = 6,250

Two ways to illustrate this:

  • The chart would not fit on one page, but would need 6,250 pages. 
    • That’s a stack that is 62.5 centimeters tall. [If one page is 0.1 mm thick]
    • That’s a stack of 30 books [If one book is 200 pages. 6250 / 200 = 31.25 books]
  • If the chart for the 100 trillion people is 30 cm high, then a chart that shows the future that is 6250-times as long would be 62.5 metres high.
    • 6250 * 30 cm = 62.5 metres

625 quadrillion relative to today’s population

The ratio between today’s world population and the future world population:

625,000,000,000,000,000 / 7,953,952,577 = 78,577,285 

The ratio between future people and all people alive today would be 78.6 million to one.

78,577,285 meter are 78,577 kilometer

Making the beach 17 meter wide means it would be 4,622km long (78,577/17). These are 2872 miles.