extinction rate
Quick Summary
Extinction refers to the complete disappearance of a species. While extinction is a natural process, the current rate at which species are disappearing is alarmingly high, estimated to be 1,000 to 10,000 times greater than the natural, or background, rate. This accelerated rate is primarily driven by human activities such as habitat destruction, pollution, overhunting, and climate change.12
There have been five major mass extinction events in Earth's history, characterized by a significant loss of species across a wide geographic area within a short geological timeframe. These events, caused by factors like asteroid impacts or widespread volcanism, drastically altered Earth's biosphere. Scientists believe we are currently experiencing a sixth mass extinction, largely due to human impact. This ongoing event threatens a substantial percentage of Earth's species, with projections suggesting a loss of 30-50% of extant species by the mid-21st century.32
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conservationHow many species are there?Any absolute estimate of extinction rate, such as extinctions per year, requires knowledge of how many species there are. Unfortunately, this number is not known with any great degree of certainty, and the problems of estimating it are formidable. Taxonomists have described—that is, have given names to—about 1.9 million…
Read MoreAny absolute estimate of extinction rate, such as extinctions per year, requires knowledge of how many species there are. Unfortunately, this number is not known with any great degree of certainty, and the problems of estimating it are formidable. Taxonomists have described—that is, have given names to—about 1.9 million…
Read More- conservationHow many species are there?
…likely to be so if extinction rates in widely different species groups and regions turn out to be broadly similar.
Read More…likely to be so if extinction rates in widely different species groups and regions turn out to be broadly similar.
Read More - conservationCalculating background extinction rates
To make comparisons of present-day extinction rates conservative, assume that the normal rate is just one extinction per million species per year. This then is the benchmark—the background rate against which one can compare modern rates. For example, given a sample of 10,000 living described species (roughly the number of…
Read MoreTo make comparisons of present-day extinction rates conservative, assume that the normal rate is just one extinction per million species per year. This then is the benchmark—the background rate against which one can compare modern rates. For example, given a sample of 10,000 living described species (roughly the number of…
Read More - conservationRecent extinction rates
To what extent has modern human activity increased extinction rates above the background rate? This discussion presents five well-known case histories of recent extinctions. From them, some general features can be deduced about recent extinctions that also provide clues to the future.
Read MoreTo what extent has modern human activity increased extinction rates above the background rate? This discussion presents five well-known case histories of recent extinctions. From them, some general features can be deduced about recent extinctions that also provide clues to the future.
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- conservationCalculating relative rates of extinction
To show how extinction rates are calculated, the discussion will focus on the group that is taxonomically the best-known—birds. The modern process of describing bird species dates from the work of the 18th-century Swedish botanist Carolus Linnaeus in 1758. Even at that…
Read MoreTo show how extinction rates are calculated, the discussion will focus on the group that is taxonomically the best-known—birds. The modern process of describing bird species dates from the work of the 18th-century Swedish botanist Carolus Linnaeus in 1758. Even at that…
Read More - conservationPredicting future rates of extinction
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