<p>When or if the current interglacial ends, what sort of extinction level can we expect, and what sort of organisms and ecosystems are affected ?
How does this compare with the current extinction rate, both in the past and potentially in the future ?
Will species loss due to glaciation include the things we are currently trying to conserve ?</p>

CC BY-SA 3.0
2017-12-20T12:39:36.457Z
Your question is quite broad. Do you mean extinction of plants or animals? On land? Are you looking for "measures" of species richness and their change due to the two _extinction-reasons_?
daniel.heydebreck
CC BY-SA 3.0
2017-12-20T15:11:40.050Z
Plants and animals, yes. Land, ocean, urban, everywhere. I don't know about measures of species richness other than just a number count so if anyone can tell me that'd be appreciated.
Jimmy Widdle
CC BY-SA 3.0
2017-12-20T19:05:22.883Z
I think you first need to ask whether glaciation (Ice Ages, IOW) actually does cause any significant extinctions, rather than just moving habitats towards the equator.  I don't know of any actual data, but certainly the glacial and immediate post-glacial (pre-human, IOW) biota in North America seems much more diverse than now.  Here in the western US, there are many remnant Ice Age species that now inhabit only isolated mountain ranges.
jamesqf
CC BY-SA 3.0
2017-12-21T19:33:07.210Z
OK so I had to do my own search for this topic

https://www.sciencedaily.com/releases/2017/03/170306091927.htm

"Cold extermination: One of greatest mass extinctions was due to an ice age and not to Earth's warming"
The Earth has known several mass extinctions over the course of its history... Over _95% of marine species disappeared_...researchers have now discovered that this extinction took place _during a short ice age_ which preceded the global climate warming.....this ice age which lasted 80,000 years was _sufficient to eliminate much of marine life_."

So is this possible again ?
Jimmy Widdle
CC BY-SA 3.0
2017-12-21T19:51:06.140Z
@Jimmy Widdle: The P-T extinction is NOT what we generally think of as an Ice Age.  Even if this one paper is supported by further research, there were a LOT of other factors at work.  Likewise a "snowball Earth" event would cause a lot of extinctions, but it's not at all the same as the geologically-recent Ice Ages.
jamesqf
CC BY-SA 3.0
2017-12-21T20:14:05.547Z
@jamesqf But the researchers say an 80,000 year ice age killed 95% of marine species. What are your objections to this claim ?
Jimmy Widdle
CC BY-SA 3.0
2017-12-22T04:38:02.213Z
@Jimmy Widdle: 1) Lots of other researchers have different ideas about just what happened during the P-T extinction.  2) If this scenario did play out, it is much more like a nuclear winter than the normal Milankovic cycle-driven Ice Ages that we've experienced in the geologically recent past.  3)  There was much else happening during the P-T.  E.g. they suggest SO2-driven cooling as causing decreased temperatures, but that should also cause acid rain & ocean acidification, unlike a "normal" Ice Age.
jamesqf
CC BY-SA 3.0
2017-12-22T15:00:27.237Z
@jamesqf  Those seem like reasonable points. But if, or rather when, we get a return to glaciation with Ice as far as France and California it's hard to see that as anything but catastrophic for a large proportion of current life forms. I know, in our current era of climate change, the idea that our efforts to preserve our interglacial biosphere may well be just a temporary respite, but that's what it is isn't it - unless we take really drastic steps to extend the warm period ?
Jimmy Widdle
CC BY-SA 3.0
2017-12-22T19:00:58.063Z
@Jimmy Widdle: Why would it be catastrophic, unless it happened suddenly?  Different species just move their ranges equatorwards, or as with the montain refugia that host boreal species today, downslope.  You just have to look at the biodiversity during the last Ice Age - or for that matter, in areas north of the Arctic circle today - to see that conditions were not hostile to life or biodiversity.  Re extending the "warm period", I'd suggest thinking of it as the "really a bit too warm period" instead.
jamesqf
CC BY-SA 3.0
2017-12-23T01:14:50.123Z
@jamesqf What is sudden ? I take it you don't believe that if there was a mile of ice over where you are now, that the life on that ice would be more diverse than what you are currently surrounded by ? Maybe you work on an antarctic base ? Do you expect all the species to squash in around the tropics ?
Jimmy Widdle
CC BY-SA 3.0
2017-12-23T19:38:58.543Z
@Jimmy Widdle: Well, where I am now is the western edge of the Great Basin.  During the Pleistocene (which encompassed all the recent Ice Ages), the climate was cooler and wetter than today, with many large pluvial lakes, and varied animal life: http://www.onlinenevada.org/articles/ice-age-nevada-and-lake-lahontan  You seem to be holding the mistaken idea that an Ice Age covers the whole Earth with glaciers.  This is not so: in the recent Ice Age, the maximum extent was about upstate New York, south of the Great Lakes, then along the Canadian border.
jamesqf
CC BY-SA 3.0
2017-12-24T14:13:57.800Z
@jamesqf Well, ok, and I know that the ice sheets weren't global. But even now the northren latitudes aren't as biodiverse as equatorial ones. The Canadian tundra isn't anything like the Amazon jungle, and even less so are the polar ice caps - trees don't grow well on ice.
https://i2.wp.com/www.savingspecies.org/wp-content/uploads/2012/09/number-of-animal-species-world-map-med.jpg?w=961
Jimmy Widdle
CC BY-SA 3.0
2017-12-25T18:56:56.553Z
@Jimmy Widdle: Trees may not grow on ice, but they're certainly capable of adjusting their range as climate varies.  Most tree species survived quite well through the last several Ice Ages, as did other plants and animals.  Also consider that the lack of at least large animal species in circumpolar areas today is due to humans having killed off most of them after the last Ice Age.  Mammoths, mastodons, glyptodonts, giant sloths, dire wolves, cave bears... https://en.wikipedia.org/wiki/Pleistocene_megafauna
jamesqf
CC BY-SA 3.0
2017-12-26T11:57:59.097Z
Trees that have a large range might survive, they seem pretty resilient, but they only account for a small proportion of species. Species can't alter their ranges forever, would you expect the tropics to be able to accommodate all the new species that moved down from temperate areas ? I think widespread extinctions are likely during a glaciation but it's a laborious search.
https://theconversation.com/ice-age-flora-extinction-reveals-fresh-plant-biodiversity-clues-12174

Some numbers to show biodiversity through glaciations would help.
Jimmy Widdle
<mass-extinction>
How does extinction caused by human activity compare to extinction caused by glaciation?
Jimmy Widdle
# How does extinction caused by human activity compare to extinction caused by glaciation?

(Asked by: username_0 on 2017-12-20)

When or if the current interglacial ends, what sort of extinction level can we expect, and what sort of organisms and ecosystems are affected ?
How does this compare with the current extinction rate, both in the past and potentially in the future ?
Will species loss due to glaciation include the things we are currently trying to conserve ?

**Tags:** mass-extinction

> **Comments:**
> **username_1**: Your question is quite broad. Do you mean extinction of plants or animals? On land? Are you looking for "measures" of species richness and their change due to the two _extinction-reasons_?  
> **username_0**: Plants and animals, yes. Land, ocean, urban, everywhere. I don't know about measures of species richness other than just a number count so if anyone can tell me that'd be appreciated.  
> **username_2**: I think you first need to ask whether glaciation (Ice Ages, IOW) actually does cause any significant extinctions, rather than just moving habitats towards the equator.  I don't know of any actual data, but certainly the glacial and immediate post-glacial (pre-human, IOW) biota in North America seems much more diverse than now.  Here in the western US, there are many remnant Ice Age species that now inhabit only isolated mountain ranges.  
> **username_0**: OK so I had to do my own search for this topic  https://www.sciencedaily.com/releases/2017/03/170306091927.htm  "Cold extermination: One of greatest mass extinctions was due to an ice age and not to Earth's warming" The Earth has known several mass extinctions over the course of its history... Over _95% of marine species disappeared_...researchers have now discovered that this extinction took place _during a short ice age_ which preceded the global climate warming.....this ice age which lasted 80,000 years was _sufficient to eliminate much of marine life_."  So is this possible again ?  
> **username_2**: @username_0: The P-T extinction is NOT what we generally think of as an Ice Age.  Even if this one paper is supported by further research, there were a LOT of other factors at work.  Likewise a "snowball Earth" event would cause a lot of extinctions, but it's not at all the same as the geologically-recent Ice Ages.  
> **username_0**: @username_2 But the researchers say an 80,000 year ice age killed 95% of marine species. What are your objections to this claim ?  
> **username_2**: @username_0: 1) Lots of other researchers have different ideas about just what happened during the P-T extinction.  2) If this scenario did play out, it is much more like a nuclear winter than the normal Milankovic cycle-driven Ice Ages that we've experienced in the geologically recent past.  3)  There was much else happening during the P-T.  E.g. they suggest SO2-driven cooling as causing decreased temperatures, but that should also cause acid rain & ocean acidification, unlike a "normal" Ice Age.  
> **username_0**: @username_2  Those seem like reasonable points. But if, or rather when, we get a return to glaciation with Ice as far as France and California it's hard to see that as anything but catastrophic for a large proportion of current life forms. I know, in our current era of climate change, the idea that our efforts to preserve our interglacial biosphere may well be just a temporary respite, but that's what it is isn't it - unless we take really drastic steps to extend the warm period ?  
> **username_2**: @username_0: Why would it be catastrophic, unless it happened suddenly?  Different species just move their ranges equatorwards, or as with the montain refugia that host boreal species today, downslope.  You just have to look at the biodiversity during the last Ice Age - or for that matter, in areas north of the Arctic circle today - to see that conditions were not hostile to life or biodiversity.  Re extending the "warm period", I'd suggest thinking of it as the "really a bit too warm period" instead.  
> **username_0**: @username_2 What is sudden ? I take it you don't believe that if there was a mile of ice over where you are now, that the life on that ice would be more diverse than what you are currently surrounded by ? Maybe you work on an antarctic base ? Do you expect all the species to squash in around the tropics ?  
> **username_2**: @username_0: Well, where I am now is the western edge of the Great Basin.  During the Pleistocene (which encompassed all the recent Ice Ages), the climate was cooler and wetter than today, with many large pluvial lakes, and varied animal life: http://www.onlinenevada.org/articles/ice-age-nevada-and-lake-lahontan  You seem to be holding the mistaken idea that an Ice Age covers the whole Earth with glaciers.  This is not so: in the recent Ice Age, the maximum extent was about upstate New York, south of the Great Lakes, then along the Canadian border.  
> **username_0**: @username_2 Well, ok, and I know that the ice sheets weren't global. But even now the northren latitudes aren't as biodiverse as equatorial ones. The Canadian tundra isn't anything like the Amazon jungle, and even less so are the polar ice caps - trees don't grow well on ice. https://i2.wp.com/www.savingspecies.org/wp-content/uploads/2012/09/number-of-animal-species-world-map-med.jpg?w=961  
> **username_2**: @username_0: Trees may not grow on ice, but they're certainly capable of adjusting their range as climate varies.  Most tree species survived quite well through the last several Ice Ages, as did other plants and animals.  Also consider that the lack of at least large animal species in circumpolar areas today is due to humans having killed off most of them after the last Ice Age.  Mammoths, mastodons, glyptodonts, giant sloths, dire wolves, cave bears... https://en.wikipedia.org/wiki/Pleistocene_megafauna  
> **username_0**: Trees that have a large range might survive, they seem pretty resilient, but they only account for a small proportion of species. Species can't alter their ranges forever, would you expect the tropics to be able to accommodate all the new species that moved down from temperate areas ? I think widespread extinctions are likely during a glaciation but it's a laborious search. https://theconversation.com/ice-age-flora-extinction-reveals-fresh-plant-biodiversity-clues-12174  Some numbers to show biodiversity through glaciations would help.  

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## 0 answers

