<p>ONE WAY to judge atmospheric CO2 of primitive prehistoric environments is to gauge geologic fossil plants by taxonomic type and geographic source (Taking into account continental drift) Finding tropical variant plant types in areas with now temperate/cold climate.</p>

CC BY-SA 4.0
2021-09-30T06:49:09.470Z
2021-09-30T06:49:09.470Z
LazyReader
<p>According to Mann and Kump (2015),</p>
<blockquote>
<p>Geologic proxies are characteristics of sedimentary rocks that we can
use to infer ancient environmental conditions. Climate scientists
study proxies because there are no thermometer records or samples of
ancient air from the geologic past. Proxies may even include the pores
on fossil leaves: when atmospheric CO<sub>2</sub> levels are low, plants need
more pores to bring in more CO<sub>2</sub>. Under the microscope, well-preserved
fossils reveal the number of pores; comparing this pore density to
that of living plants allows scientists to establish CO<sub>2</sub> levels in the
geologic past.</p>
</blockquote>
<p>However, in order to use this comparison to make inferences about CO<sub>2</sub> levels, it seems to me that this would require establishing that everything else is held equal. If this is not established, it seems to me that this would not allow one to use plant pores as proxies for past CO<sub>2</sub> levels and thus climate change. Therefore, my question is, how do researchers attempt to hold all else equal when comparing the pore density of fossilized plants to living plants to establish a causal relation between past CO<sub>2</sub> levels and plant pores density?</p>
<p>Reference:</p>
<p>Mann, M. E. and L. R. Kump (2015). Dire Predictions: Understanding Climate Change 2nd Edition. DK Publishing.</p>

CC BY-SA 4.0
2021-03-28T16:46:58.893Z
double posted https://biology.stackexchange.com/questions/100020/how-reliable-are-fossilized-plant-spore-proxies-of-past-climate-change
trond hansen
CC BY-SA 4.0
2021-03-29T05:00:22.760Z
i=Including a link to where you got this is very helpful, Showing some attempt to answer this on your own would be even more helpful.
John
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2021-09-28T12:09:18.900Z
Related: https://earthscience.stackexchange.com/q/34/18081
Jean-Marie Prival
CC BY-SA 4.0
2021-10-31T07:38:46.500Z
I think you mean to refer to plant **pores**, not spores, in the question?
njuffa
<climate-change><co2><plant>
How is causality between past CO$_2$ levels and fossilized plant pores proxies established?
Ryan da Silva
# How is causality between past CO$_2$ levels and fossilized plant pores proxies established?

(Asked by: username_0 on 2021-03-27)

According to Mann and Kump (2015),

> Geologic proxies are characteristics of sedimentary rocks that we can
> use to infer ancient environmental conditions. Climate scientists
> study proxies because there are no thermometer records or samples of
> ancient air from the geologic past. Proxies may even include the pores
> on fossil leaves: when atmospheric CO2 levels are low, plants need
> more pores to bring in more CO2. Under the microscope, well-preserved
> fossils reveal the number of pores; comparing this pore density to
> that of living plants allows scientists to establish CO2 levels in the
> geologic past.

However, in order to use this comparison to make inferences about CO2 levels, it seems to me that this would require establishing that everything else is held equal. If this is not established, it seems to me that this would not allow one to use plant pores as proxies for past CO2 levels and thus climate change. Therefore, my question is, how do researchers attempt to hold all else equal when comparing the pore density of fossilized plants to living plants to establish a causal relation between past CO2 levels and plant pores density?

Reference:

Mann, M. E. and L. R. Kump (2015). Dire Predictions: Understanding Climate Change 2nd Edition. DK Publishing.

**Tags:** climate-change, co2, plant

> **Comments:**
> **username_1**: double posted https://biology.stackexchange.com/questions/100020/how-reliable-are-fossilized-plant-spore-proxies-of-past-climate-change  
> **username_2**: i=Including a link to where you got this is very helpful, Showing some attempt to answer this on your own would be even more helpful.  
> **username_3**: Related: https://earthscience.stackexchange.com/q/34/18081  
> **username_4**: I think you mean to refer to plant **pores**, not spores, in the question?  

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## 1 answers

### Answer by username_5 on 2021-09-30. Score: -2

ONE WAY to judge atmospheric CO2 of primitive prehistoric environments is to gauge geologic fossil plants by taxonomic type and geographic source (Taking into account continental drift) Finding tropical variant plant types in areas with now temperate/cold climate.


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