The Science is Rocky

The last time I gave a thought to geologic time measurements (eons, eras, epochs, etc.) was in college. It was my senior year, when I took a popular geology "gut" (easy) course whose only requirement was to pass a multiple-choice open book final. Unlike most of my classmates, I did attend the weekly lectures. After all, annual tuition at the East Coast private university was an astronomical $3,400, and I had to get my money's worth.

But back to geologic time. Starting from the largest unit, we are living in the Phanerozoic eon, Cenozoic era, Quaternary period, and Holocene epoch. An influential body of geologists has decided that [bold added]

Humanity’s influence on the Earth is so great, an entirely new geological epoch called the Anthropocene should be declared.

Geologic time periods are distinguished by strata, i.e., they have different chemical compositions, fossils, etc.

The Anthropocene epoch should begin in about 1950, as man-made developments ended the geological time defined by the current epoch, the Holocene, the scientists said. The Holocene encompasses the 12,000 years since the last ice age.

Mid-20th century phenomena, such as carbon dioxide emissions, rising sea levels, the global mass extinction of species and deforestation, have ended the Holocene epoch, the scientists said. The Anthropocene would be defined geologically by the effects of nuclear bomb tests, plastic pollution, concrete and more, according to scientists.

Two comments:

1) Again, humankind has lived through an important historical event (1950, the start of the Anthropocene epoch) without knowing it;

2) Plastic pollution, mass extinction, deforestation--any time scientists tell you that they keep their language value-neutral, tell them they're full of it, which is not a value-neutral statement. For example, they could have said that the Anthropocene stratum is distinguished by "a marked increase in polyethylene molecules" instead of describing the phenomenon as "plastic pollution" but hey, what do I know, I just took Rocks for Jocks 40 years ago.