Background extinction rate, also known as ‘normal extinction rate’, refers to the standard rate of extinction in earth’s geological and biological history before humans became a primary contributor to extinctions. This is primarily the pre-human extinction rates during periods in between major extinction events.
Overview
Extinctions are a normal part of the evolutionary process, and the background extinction rate is a measurement of “how often” they naturally occur. Normal extinction rates are often used as a comparison to present day extinction rates, to illustrate the higher frequency of extinction today than in all periods of non-extinction events before it.
Background extinction rates have not remained constant, although changes are measured over geological time, covering millions of years.
Measurement
Background extinction rates are typically measured three different ways. The first is simply the number of species that normally go extinct over a given period of time. For example, at the background rate one species of bird will go extinct every estimated 400 years. Another way the extinction rate can be given is in million species years (MSY). For example, there is approximately one extinction estimated per million species years. From a purely mathematical standpoint this means that if there are a million species on the planet earth, one would go extinct every year, while if there was only one species it would go extinct in one million years, etc. The third way is in giving species survival rates over time. For example, given normal extinction rates species typically exist for 5–10 hundred thousand years before going extinct.
Despite MEAs, the rate of fossil fuel carbon dioxide emissions increase unabated. With regard to biodiversity, "Species are going extinct at rates 1,000 times the background rates typical of the Earth's past."
... and resource depletion escalating at unprecedented rates ... Species extinction rates are estimated to be 10-100 times higher than the natural background rate, driven by habitat loss and deforestation.
On average, "the background extinction rate" will bump off about one species, per million species, per year ... That rate is around 600 times faster than the normal background extinction rate, and there ...
This is known as the background extinction rate ... times faster than this background rate, leading to the suggestion that we may even be in the midst of the sixth mass extinction in our planet’s history.
Species are currently disappearing hundreds to thousands of times faster than the normal background rate of extinction, and with rapid climate change and continued human expansion on the horizon, this trend shows no sign of diminishing.
The natural or 'background' extinction rate is about 10 to 100 species a year ... rates ... But their recovery cannot compensate for rapid global extinction rates, with more and more species under threat.
Yet, contrary to its seemingly gradual pace, species are vanishing 1,000 times faster than the natural background rate of extinction – a pace that surpasses even the aftermath of the comet that led to the demise of the dinosaurs.
Is the Anthropocene real? That is, the vigorously debated concept of a driven by humans ... Advertisement ... 1. Carbon In The Atmosphere ... Advertisement ... 2 ... Advertisement ... 3 ... 4 ... The rate of extinctions is now many times above background levels, and is accelerating.
“Incorporating estimates of the true number of invertebrate extinctions leads to the conclusion that the rate vastly exceeds the background rate and that we may indeed be witnessing the start of the SixthMassExtinction,” they say.
This is much faster than the expected “background” extinction rate, or the rate at which species would naturally die off without outside influence — in the absence of human beings, these 73 genera ...
... shift or natural disaster but by human activity — the rate of extinctions, dark or not, is intensifying. Extinction rates today are estimated at 1,000 and 10,000 times the planet’s background rate.
This is 500 times faster than the “background extinction rate” – the rate of extinctions absent from human interference ... Other studies have put the modern extinction rate closer to 1,000 times faster than pre-human extinction rates.
In reality, however, extinctions are occurring at least 100 times faster than this so-called background rate, and 10 times faster than the planetary boundary limit.
