Patrick Doncaster , 7 November , one of the then 7,,, rising by per minute, 79 million per year. Evolution of life on Earth 4,,, earliest life on Earth: single-celled prokaryotic Archaea Hadean Eon , 3. Human evolution 2,, earliest human, Homo sp. Years ago. Evolution of life on Earth. Homo habilis in Africa , using stone tools for cleaving meat from bone.
Homo antecessor in western Europe Atapuerca , Spain , closely related to the last common ancestor of Neanderthals, Denisovans and modern humans. Homo sapiens enter Eurasia Greece : first of multiple dispersals out of Africa by humans with early modern traits, including globular braincase and descended larynx facilitating spoken language. There are fossils, of course. But the fraction of life that gets fossilized is always minuscule and varies a lot depending on time and habitat.
It would be easy, therefore, to miss an industrial civilization that lasted only , years—which would be times longer than our industrial civilization has made it so far. Given that all direct evidence would be long gone after many millions of years, what kinds of evidence might then still exist? Future researchers should see this in characteristics of nitrogen showing up in sediments from our era. Likewise our relentless hunger for the rare-Earth elements used in electronic gizmos.
They might also show up in future sediments, too. Even our creation, and use, of synthetic steroids has now become so pervasive that it too may be detectable in geologic strata 10 million years from now. Wind, sun, and waves grind down large-scale plastic artifacts, leaving the seas full of microscopic plastic particles that will eventually rain down on the ocean floor, creating a layer that could persist for geological timescales.
The big question is how long any of these traces of our civilization will last. In our study, we found that each had the possibility of making it into future sediments. The more fossil fuels we burn, the more the balance of these carbon isotopes shifts. Atmospheric scientists call this shift the Suess effect, and the change in isotopic ratios of carbon due to fossil-fuel use is easy to see over the past century. Increases in temperature also leave isotopic signals.
These shifts should be apparent to any future scientist who chemically analyzes exposed layers of rock from our era. Along with these spikes, this Anthropocene layer might also hold brief peaks in nitrogen, plastic nanoparticles, and even synthetic steroids.
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