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There are three different ways to calculate background extinction rate. [5] 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. [6] Another way the extinction rate can be given is in million species ...
Extinction Date Probable causes [2] Quaternary: Holocene extinction: c. 10,000 BC – Ongoing: Humans [3] Quaternary extinction event: 640,000, 74,000, and 13,000 years ago: Unknown; may include climate changes, massive volcanic eruptions and Humans (largely by human overhunting) [4] [5] [6] Neogene: Pliocene–Pleistocene boundary extinction: 2 Ma
The report concluded that global warming of 2 °C (3.6 °F) over the preindustrial levels would threaten an estimated 5% of all the Earth's species with extinction even in the absence of the other four factors, while if the warming reached 4.3 °C (7.7 °F), 16% of the Earth's species would be threatened with extinction.
More significantly, the current rate of global species extinctions is estimated as 100 to 1,000 times "background" rates (the average extinction rates in the evolutionary time scale of planet Earth), [71] [72] faster than at any other time in human history, [73] [74] while future rates are likely 10,000 times higher. [72]
The surviving populations are in continual decline in 43% of those that are threatened. Since the mid-1980s the actual rates of extinction have exceeded 211 times rates measured from the fossil record. [148] However, "The current amphibian extinction rate may range from 25,039 to 45,474 times the background extinction rate for amphibians."
These papers utilized the compendium to track origination rates (the rate that new species appear or speciate) parallel to extinction rates in the context of geological stages or substages. [60] A review and re-analysis of Sepkoski's data by Bambach (2006) identified 18 distinct mass extinction intervals, including 4 large extinctions in the ...
It is estimated that, because of human activities, current species extinction rates are about 1000 times greater than the background extinction rate (the 'normal' extinction rate that occurs without additional influence). [37] According to the IUCN, out of all species assessed, over 42,100 are at risk of extinction and should be under ...
[47] [48] For example, coral reefs—which are biodiversity hotspots—will be lost by the year 2100 if global warming continues at the current rate. [49] [50] Still, it is the general habitat destruction (often for expansion of agriculture), not climate change, that is currently the bigger driver of biodiversity loss.