Optical space telescope
- CO2 + NO2
Reflected light
S4
After the peak of high technology, people live by subsistence, simple tools, and artisanal crafts. Rituals and oral traditions reinforce belonging to the biosphere, while settlements migrate with seasonal and planetary cycles.
Illustration of future S4. Wild forests, grasslands and restored ice cover Earth. People live in small seasonal camps that drift with the year, beside the overgrown ruin of a former high-technology age. One derelict satellite still circles. The description and data are on this page.
The scenario study measures every future against a fixed Earth: 7.9 billion people, each using 75 gigajoules of energy a year (592.5 EJ per year in total). An exajoule (EJ) is a billion billion joules.
The multipliers are rounded and count every world a civilization lives on. The reference is the study’s model, not a measurement of Earth today, and says nothing about how many people a planet can support.
Planetary technosignatures: industrial pollution scaling, p. 12 ↗Table 9 caption and Section 5.1, p. 18 ↗
How the scenario study describes this civilization. Where it offers more than one option, both are shown. Each line links to the table it came from.
| Economy | ScarcityTable 2, p. 5 ↗ |
|---|---|
| Politics | Rule by fewTable 2, p. 5 ↗ |
| Society | HierarchicalTable 2, p. 5 ↗ |
| Technology and nature | They partly overlapIn the paper: Some common elements with the biosphere; neither set is equalTable 4, p. 7 ↗ |
| Centers of technology | One centerIn the paper: UnipolarTable 4, p. 7 ↗ |
| How technology develops | Evolved and emergentTable 4, p. 7 ↗ |
| Smallest engineering scale | 1 nm to 1 μmTable 4, p. 7 ↗ |
Five instruments, from the observing study. “Nothing listed” means the study lists no sign for that instrument—not that this civilization has no technology.
Nothing listed for this instrument.
Radio arrayNothing listed for this instrument.
Large Interferometer for ExoplanetsNothing listed for this instrument.
Solar Gravitational LensPollution, night lights, reshaped land, satellites and haze on Earth, the Moon, Mars and Venus, compared with Earth today. Each kind of mark keeps its own units; we don’t squash them onto one scale.
| World | Mark | Amount | Measured as | Source |
|---|---|---|---|---|
| Earth | Industrial pollution | 0.038 | abundance relative to Earth 2024 | Table 6, p. 14 ↗ |
| Moon | Industrial pollution | Not given | abundance relative to Earth 2024 | Table 6, p. 14 ↗ |
| Mars | Industrial pollutionS5 and S6 include artificial greenhouse gases for terraforming Mars. | Not given | abundance relative to Earth 2024 | Table 6, p. 14 ↗ |
| Venus | Industrial pollutionS5 and S6 indicate O2 production and depletion of other constituents for terraforming Venus. | Not given | abundance relative to Earth 2024 | Table 6, p. 14 ↗ |
| Earth | Agricultural pollution | 0.29 | abundance relative to Earth 2024 | Table 6, p. 14 ↗ |
| Moon | Agricultural pollution | Not given | abundance relative to Earth 2024 | Table 6, p. 14 ↗ |
| Mars | Agricultural pollution | Not given | abundance relative to Earth 2024 | Table 6, p. 14 ↗ |
| Venus | Agricultural pollution | Not given | abundance relative to Earth 2024 | Table 6, p. 14 ↗ |
| Earth | Artificial illumination | 0.025 | intensity relative to Earth 2024 | Table 6, p. 14 ↗ |
| Moon | Artificial illumination | Not given | intensity relative to Earth 2024 | Table 6, p. 14 ↗ |
| Mars | Artificial illumination | Not given | intensity relative to Earth 2024 | Table 6, p. 14 ↗ |
| Venus | Artificial illumination | Not given | intensity relative to Earth 2024 | Table 6, p. 14 ↗ |
| Earth | Surface modification | 0.0006 | fraction of planetary surface | Table 6, p. 14 ↗ |
| Moon | Surface modification | Not given | fraction of planetary surface | Table 6, p. 14 ↗ |
| Mars | Surface modification | Not given | fraction of planetary surface | Table 6, p. 14 ↗ |
| Venus | Surface modification | Not given | fraction of planetary surface | Table 6, p. 14 ↗ |
| Earth | Satellite belt | 0.015 | density relative to Earth 2024 | Table 6, p. 14 ↗ |
| Moon | Satellite belt | Not given | density relative to Earth 2024 | Table 6, p. 14 ↗ |
| Mars | Satellite belt | Not given | density relative to Earth 2024 | Table 6, p. 14 ↗ |
| Venus | Satellite belt | Not given | density relative to Earth 2024 | Table 6, p. 14 ↗ |
| Earth | Contaminated aerosol | Not given | density relative to Earth 2024 | Table 6, p. 14 ↗ |
| Moon | Contaminated aerosol | Not given | density relative to Earth 2024 | Table 6, p. 14 ↗ |
| Mars | Contaminated aerosol | Not given | density relative to Earth 2024 | Table 6, p. 14 ↗ |
| Venus | Contaminated aerosol | Not given | density relative to Earth 2024 | Table 6, p. 14 ↗ |
Signs of technology across the Solar System come from the scenario study. Collapse and recovery come from a separate study that simulates each future for 1,000 years.
Collapses in every run and has the lowest reported mean duty cycle, with frequent deep collapses.
The gases and temperature the observing study gives this future’s Earth. Where the paper leaves a value out, we show “Not given” rather than zero.
| Gas or property | Value | Unit | Source |
|---|---|---|---|
| Mean Temperature | 288 | K | Table 1, p. 4 ↗ |
| CO2 | 290 | ppm | Table 1, p. 4 ↗ |
| CH4 | 0.96 | ppm | Table 1, p. 4 ↗ |
| NOx | 0.17 | ppb | Table 1, p. 4 ↗ |
| N2O | 220 | ppb | Table 1, p. 4 ↗ |
| NH3 | 4.3 | ppb | Table 1, p. 4 ↗ |
| CFC-11 | Not given | ppb | Table 1, p. 4 ↗ |
| CFC-12 | Not given | ppb | Table 1, p. 4 ↗ |
| NF3 | 2.5 | ppt | Table 1, p. 4 ↗ |
| SF6 | 11 | ppt | Table 1, p. 4 ↗ |
| CF4 | 87 | ppt | Table 1, p. 4 ↗ |
| SO2, Stratospheric | Not given | ppb | Table 1, p. 4 ↗ |
| Na Emission | 0.042 | erg s^-1 cm^-2 | Table 1, p. 4 ↗ |
| Laser Emission, 1.064 um | Not given | MW | Table 1, p. 4 ↗ |
Stories and objects artists made inside this future. They’re fiction, not evidence. Works whose creators reserve all rights are linked, never copied here.
Clara Mae Gonzales
All rights reservedView the original ↗