# extinction rate **URL:** \ **Category:** Factual Questions\ **Created:** [July 24, 2000, 5:38pm UTC](https://boards.straightdope.com/t/extinction-rate/26663 "2000-07-24T17:38:24Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![Phobos](https://avatars.discourse-cdn.com/v4/letter/p/3d9bf3/32.png) [@Phobos](https://boards.straightdope.com/u/Phobos)\ **Post date:** [July 24, 2000, 5:38pm UTC](https://boards.straightdope.com/t/extinction-rate/26663/1 "2000-07-24T17:38:24Z")
I’ve heard a wide variety of claims on the rate of extinction of species nowadays…including some on the order of 10s per day (or something like that). I think there’s no way to accurately measure this, but are there any reliable sources on this? ---
**Author:** ![tcburnett](https://avatars.discourse-cdn.com/v4/letter/t/c5a1d2/32.png) [@tcburnett](https://boards.straightdope.com/u/tcburnett)\ **Post date:** [July 24, 2000, 10:39pm UTC](https://boards.straightdope.com/t/extinction-rate/26663/2 "2000-07-24T22:39:58Z")
All extinction rate estimates made by scientists are theoretically extrapolated from various historical and observable rates. But they are only guesses since we have no idea how many species we cause to go extinct that we do not know exist. I find no new information in the following, but I include them with an apology: [http://bioweb.cs.earlham.edu/9-12/formation/](http://bioweb.cs.earlham.edu/9-12/formation/) [http://fig.cox.miami.edu/Faculty/Tom/bil160sp98/10\_extinct.html](http://fig.cox.miami.edu/Faculty/Tom/bil160sp98/10_extinct.html) [http://www.portalmarket.com/earthportals/extinct.html](http://www.portalmarket.com/earthportals/extinct.html) [http://biology.uoregon.edu/Biology\_www/Online\_classes/Bi103s97/l9/tsld005.htm](http://biology.uoregon.edu/Biology_www/Online_classes/Bi103s97/l9/tsld005.htm) ---
**Author:** ![wevets](https://avatars.discourse-cdn.com/v4/letter/w/e9a140/32.png) [@wevets](https://boards.straightdope.com/u/wevets)\ **Post date:** [July 26, 2000, 1:07am UTC](https://boards.straightdope.com/t/extinction-rate/26663/3 "2000-07-26T01:07:28Z")
Tc’s right, extinction rates are pretty much guesswork with the notable exceptions of birds and mammals in well-studied or heavily populated habitats. For anything else, especially prehistoric extinctions and invertebrates, the numbers are only a ballpark figure. Perhaps one of the most reliable sources would be the [International Union for the Conservation of Nature (IUCN)](http://www.iucn.org/), which acts as a clearinghouse for data from several hundred national governments, NGOs, and the UN. Also, the number of recorded extinctions from 1600 to 1989 can be found in Reid and Miller. 1989. _Keeping Options Alive: The Scientific Basis for Conserving Biodiversity_. World Resources Institute, Washington DC. They give a documented rate of one species of bird or mammal going extinct every decade during the period 1600-1700, increasing to one bird or mammal species per year during the period 1850-1950. They also estimate that somewhere between 2% and 11% of the world’s total species go extinct every decade. Including unknown species, E. O. Wilson has estimated (in 1989. Threats to biodiversity. [_Scientific American_](http://www.sciam.com/). Vol. 261: 108-116.) that 0.2% or 0.3% of species are lost each year, translating into 68 species a day or 3 species an hour (and that was a somewhat conservative estimate!) if there are 10 million species in the world. I suspect the [U.N. Environment Programme](http://www.unep-wcmc.org/) maintains more up to date figures than I’ve just posted, but I’ve been having trouble with their search feature. ---
**Author:** ![wevets](https://avatars.discourse-cdn.com/v4/letter/w/e9a140/32.png) [@wevets](https://boards.straightdope.com/u/wevets)\ **Post date:** [July 26, 2000, 1:17am UTC](https://boards.straightdope.com/t/extinction-rate/26663/4 "2000-07-26T01:17:57Z")
How about a numbers game? Let’s take Wilson’s 0.2% of all species lost each year rate: If there are 2 million species, we lose 4000 species a year or 11 a day. If there are 5 million, it’s 27 a day. If there are 30 million, it’s 164 a day. 2 million is about the low end estimate for the number of species in the world, while 30 million is the largest estimate I’ve seen. ---
**Author:** ![Phobos](https://avatars.discourse-cdn.com/v4/letter/p/3d9bf3/32.png) [@Phobos](https://boards.straightdope.com/u/Phobos)\ **Post date:** [July 26, 2000, 12:56pm UTC](https://boards.straightdope.com/t/extinction-rate/26663/5 "2000-07-26T12:56:23Z")
thanks for the input. the numbers are staggaring, so it’s good to know what kind of evidence backs it up.