Orders of Magnitude: A Timeline
A look at the influence of mankind over time
by Eric Sorensen
In his landmark investigation of geology, Annals of the Former World, John McPhee meditated on how hard it is to comprehend the brevity of a human lifetime against the enormity of geologic time. Even geologists have a hard time getting it.
“They wonder to what extent they truly sense the passage of millions of years,” McPhee writes. “They wonder to what extent it is possible to absorb a set of facts and move with them, in a sensory manner, beyond the recording intellect and into the abyssal eons. Primordial inhibition may stand in the way. On the geologic time scale, a human lifetime is reduced to a brevity that is too inhibiting to think about.”
Given humanity’s rising influence on the planet, it’s worth a try.
Formation of Solar System, including Earth.
Possible age for earliest microbial life
Massive production of dioxygen, or O2, creates the Great Oxygenation Event, possibly wiping out anaerobic life.
Age of Earth’s oldest known petroleum.
Dawn of sexual reproduction. According to the fossil record, it started with the B. pubescens, a type of alga.
Age of most of the world’s known oil deposits.
Largest of five known mass extinctions, known as the end-Permian or the Great Dying. Ninety-six percent of marine life and 70 percent of terrestrial vertebrate species disappear.
Origin of the human genus Homo.
Inhabitants of Abu Hureyra, in Syria, cultivate rye, auguring the birth of agriculture.
Younger Dryas, a 1,300-year period of cooling, ends. Cultivation of wheat and barley begins.
A stone wall is built around Tell es-Sultan, the ancient city of Jericho, making it the world’s earliest known urban fortification.
Human population stands at 300 million.
Europeans arrive in the Western Hemisphere.
A new era dawns as the world’s hemispheres connect, species are exchanged between the East and West, and global trade begins to proliferate. From here out, the human influence on the planet is great enough to form a stratigraphic record, an imprint on the face of the earth, as distinct as the previous geologic epochs.
Human population is 790 million.
Thomas Robert Malthus, an English cleric and scholar, proclaims the human population is growing faster than its ability to support itself, making famine, disease, or some such “misery or vice” inevitable.
Earth’s atmosphere contains 270 to 290 parts per million of carbon dioxide
World population reaches 1 billion.
Irish Physicist John Tyndall publishes the molecular basis for the greenhouse effect.
At the Mauna Loa Observatory in Hawaii, geochemist Charles David Keeling records a CO2 concentration of 313 ppm. Subsequent rising levels, plotted over time, come to be called the “Keeling Curve.”
U.S. scientists warn that man’s burning of fossil fuels is increasing levels of atmospheric carbon dioxide. Those rising levels “may be sufficient to produce measurable and perhaps marked changes in climate.”
Paul Crutzen, a Nobel laureate in chemistry, proposes calling the current epoch the Anthropocene, a period in which humans influence the earth as powerfully as the biogeophysical forces that preceded them.
Electric car sales in the U.S. doubles.
A total of 322 species of vertebrates have gone extinct since 1500 while remaining species have declined by one-fourth.
The new year has begun with carbon dioxide concentrations above 400 parts per million. CO2 levels are now higher than they’ve ever been in mankind’s history.