"Today, at 380 ppm our atmosphere is CO2-impoverished"

[bhikkhu]

"Following the Carboniferous Period, the Permian Period and Triassic Period witnessed predominantly desert-like conditions, accompanied by one or more major periods of species extinctions. CO2 levels began to rise during this time because there was less erosion of the land and therefore reduced opportunity for chemical reaction of CO2 with freshly exposed minerals. Also, there was significantly less plant life growing in the proper swamplands to sequester CO2 through photosynthesis and rapid burial.

It wasn't until Pangea began breaking up in the Jurassic Period that climates became moist once again. Carbon dioxide existed then at average concentrations of about 1200 ppm, but has since declined. Today, at 380 ppm our atmosphere is CO2-impoverished, although environmentalists, certain political groups, and the news media would have us believe otherwise."

Following the Carboniferous Period, the Permian Period and Triassic Period witnessed predominantly desert-like conditions, accompanied by one or more major periods of species extinctions. CO2 levels began to rise during this time because there was less erosion of the land and therefore reduced opportunity for chemical reaction of CO2 with freshly exposed minerals. Also, there was significantly less plant life growing in the proper swamplands to sequester CO2 through photosynthesis and rapid burial.

It wasn't until Pangea began breaking up in the Jurassic Period that climates became moist once again. Carbon dioxide existed then at average concentrations of about 1200 ppm, but has since declined. Today, at 380 ppm our atmosphere is CO2-impoverished, although environmentalists, certain political groups, and the news media would have us believe otherwise...."

http://www.geocraft.com/WVFossils/Carboniferous_climate.html

---------------------------------------------

In spite of some odd statements, this is actually a pretty good site I thought I'd share. Very nice graphics and explanations of Gondwanaland and Laurasia and the continental arrangements during the laying down of Carboniferous coal deposits. I've read through it all in books and so forth, but this has an interesting perspective.

One glaring omission is the role of volcanism in the ancient CO2 records and temperatures, but it is interesting that the "modern-like" CO2 and climate conditions at the end of the Carboniferous period are followed by rising CO2 and "predomintantly desert-like" conditions, for about 100 million years.

[MH1]

1. I went to the site and couldn't find an exploded view for the most recent 5 million years or so

Thus, what does this have to do with environmental conditions for supporting human life on earth?

Seems a similar chart for Mars would be just as relevant as the one you posted.

[bhikkhu]

3. That would be the key point

As you can say the planet has experienced all of this variability over hundreds of millions of years, but the human race has evolved only in the last few fractions of that.
We probably would be able to survive as a species most of the conditions on the graph, but only as desperately beaten-down isolated populations.

[tabatha]

2. What were the concentrations of oxygen at that time?

The levels of CO2 in the air and potential health problems are:

* 250 - 350 ppm – background (normal) outdoor air level
* 350- 1,000 ppm - typical level found in occupied spaces with good air exchange.
* 1,000 – 2,000 ppm - level associated with complaints of drowsiness and poor air.
* 2,000 – 5,000 ppm – level associated with headaches, sleepiness, and stagnant, stale, stuffy air. Poor concentration, loss of attention, increased heart rate and slight nausea may also be present.
* >5,000 ppm – Exposure may lead to serious oxygen deprivation resulting in permanent brain damage, coma and even death.

[bhikkhu]

4. Apparently stable for 1.5 billion years or so

http://www.draget.net/hoe/index.php?p=p8

I agree more or less on the article. The data is very interesting and stands alone well enough, while the article's analysis of the data is certainly lacking.

[tabatha]

9. I don't think humans would survive in 10% oxygen.

If at 10% oxygen, then there has to be a period when it increases to today's level - 21%.

[bhikkhu]

12. Sorry - wrong time period

I didn't notice that the graph stopped at 1 billion years ago (!).

according to http://www.ux1.eiu.edu/~cfjps/1400/atmos_origin.html

"During the Proterozoic the amount of free O2 in the atmosphere rose from 1 - 10%. Most of this was released by cyanobacteria, which increase in abundance in the fossil record 2.3 Ga. Present levels of O2 were probably not reached until ~400 Ma."

Which gives us a generally stable level of oxygen for the past few hundred million years...

You're probably right about the 10% being non-livable, at least for our species. While the percentages stay the same, at 18000 ft the density of the atmosphere is about 1/2 of sea level, so the available oxygen is about half. Above that elevation there are no cities, and from what I've read acclimatization is difficult and temporary.

[tabatha]

14. And there is the part that GWD don't consider

If too much CO2 in the atmosphere causes the ocean to be too acidic, can the cyanobacteria and other O2 emitting organisms survive? If they cannot, then O2 level in the atmosphere will decrease, and so will the chances of humans living on the earth.

To me, the most important part of the CO2 debate that GWD deniers cannot deny, is the increase in acidity of the oceans - that is going to have far-reaching consequences.

Other problems caused by humans are from nitrogen - I think that was mentioned on the opening day of the summit.

[Pholus]

5. This is fishy...

1) The slightly shaded errorbars seem to imply a correlation between the 2.
Sure it looks weak, but where are the errorbars on the temperatures? I find
it beyond first order credibility that the global temperature clamps at
a seemingly constant 25 C through history.

2) The plot at www.scotese.com clamps the temperature to 25 C not 22 C so
why is this set of temperature data different?

3) I like the previous comment about the effects of CO2. That was GOING
to be my first response.

4) Try visiting http://www.scotese.com/climate.htm and click
through the capsule descriptions of the climate in each of these
epochs.

Example: Middle Triassic: "The interior of Pangea was dry during the Triassic. The polar regions were warm, even during the winter."

Sounds like a similar climate would JUST be a winner for feeding the world.

Sorry bhikkhu, this is a FAIL.

[Pholus]

6. Corrected my subject

The original subject I used implies a level of disgust I don't feel.

However, the source temperature data on the plots doesn't seem to match my quick attempt to match to real data. The CO2 looks credible but
the temperatures smell...

I also gut level equated the original subject of this thread with some AGW whacks that claim that we NEED to flood the atmosphere with more CO2.

[bhikkhu]

7. Thanks for the links

That's an excellent set of maps and information.

Other than just being interested for the sake of learning what there is to learn, I also have the predicament of living in and working with a very RW crowd. As the only one around who has a real interest in science and climate change, I'm often posed questions like the thread heading, as in "lets see him refute this!". Its been helpful to pre-research many things online, and the discussions here have been helpful as well.

[Pholus]

10. I know the feeling

The biggest problem for me is in knowing that without dedicating a lot of time to this stuff, you really can't know what's right and wrong. My usual first tactic is to try to track down the source data. Berner's stuff is published at NASA and has a peer review history, so the CO2 levels have a first order pedigree but I sure didn't spend time trying to figure out the method or limitations on the dataset. Scotese's stuff is on a self named website implying very little peer review. That being said, it looks legit but I was not able to rapidly locate methodology/limitations or errorbars on that set. Also, how the data is plotted can be misleading since Microsoft excel loves connecting the datapoints by a smoothly drawn curve (as my students show me much to my disgust every semester). I mean, seriously. You have data POINTS and any curve you draw implies knowledge you don't have. Oh well, sorry, it's end of the semester and I'm here because I'm running away from grading lab reports at the moment.

Sadly, being trapped with RW co-workers means that hours of thoughtful inquiry into real data will be brushed off with the first bit of truthiness from the counterargument they want to be correct. I've found that it sometimes helps to fall back on the old physics professor trick of staring at them like I'm mentally dissecting them and finding a lot to be lacking. They know deep down they're BS'ing and it does unnerve them a bit to think their personal credibility might just be shrinking cause they repeated the last thing that Rush told them.

[n2doc]

15. You nail it

They really don't want to be convinced, or have an open mind. They just want to argue in the hope that you will come over to their side. Facts are just weapons to be used or discarded in the battle.

BTW, Berner's stuff is first rate. He has been estimating paleo CO2 levels for much of his life (he's emeritus now) and he is one of the finest minds in the field. I have met him once, as a graduate student, and he did not suffer fools gladly. I was happy to escape the encounter without him finding some unforeseen flaw in my thesis research.

[bhikkhu]

19. What it takes to change someone's mind...

when their "social identity" depends upon an untenable position. Regular exposure to the realities of warming (in our area - pine-bark beetle infestation, warmer winters, longer growing season, drought) is opposed by regular injections of doubt and derision, almost like a defensive clique forming their own individual reality. Simple news like the coverage of Copenhagen is a threat, met with an equal level of scoffing doubt and derision...

I have to say, I don't know anyone who has changed their mind on global warming, and in spite of much discussion I have no idea what it would take for anyone I know to change their minds. It reminds me of the old UFO mania ("can 15 million Americans be wrong?"), with all the sightings and abduction stories and so forth. The fuel for deniers is that they mostly talk to each other and cherry-pick from a huge assortment of data things that are easily misunderstood.

The one thing that I've found works in argument is the breadth of the data. If CO2 is doubted, you can throw it out and look at tree rings, or throw those out and look just at temperature data, or discard all of those things and just look at phenology...everything tells pretty much the same story, so a point must be reached where either you close your eyes to all evidence, or you just admit that global warming exists.

Yet I haven't ever seen a person change their mind.

[kristopher]

26. That's because it is a political/tribal debate, not a scientific one.

They are playing a game where all that matters is that their "team" wins.

They will no more openly change their position than a rugby player would suddenly switch sides on the field.

[lapfog_1]

8. I like the earth the way it is...

or rather, the way it was some 60 years ago or so... maybe 110 years ago.

That means a *lot* less "development" and a *lot* more forests and wild animals and coral reefs and fish in the ocean.

It was an earth that was very kind to the people that lived on it (though mother nature could and would kill you if you were unlucky or stupid).

It was an earth that could grow enough food to feed probably 3 billion people, and allow all of them some comforts and some leisure.

I do love our technology and our medicine, but I beginning to wonder if it's really worth it.

I want that planet back. With it's enormous biodiversity.

I don't give a rat's ass about natural cycles (except that we need to understand them completely). If a large asteroid is headed our way, I want us to stop it. If the climate is changing so that the oceans are too acidic for a wide variety of fish and plants to thrive and that will cause nation to war with nation over water and farm land, I want to stop that too. If we are causing it to change with our emissions of CO2, well, a great start to halting the change would be to eliminate CO2 emissions and start reducing CO2 in the atmosphere. But I don't care if we are to blame or not, if it's changing to be a climate less hospitable to us and our animal cousins, it's up to us to "fix it". Hubris, yeah, a bit. But I have that "survival of the species" gene that really wants our species to continue and to thrive.

Nature has given us a planet that allowed our species to survive and do well. Let's not make it worse for ourselves and, furthermore, lets not let nature make it worse for us either.

[tabatha]

21. +10

[MH1]

22. Excellent post.

Restoring more land to natural forest would slow the increase in CO2 in the atmosphere, regardless of whether GW is "anthropogenic" or not, right?

I am a big fan of reforestation and I wish we could just get on with it. :) (of course I realize that might not be all that's needed. But we don't have to figure out fancy technical stuff to grow more trees, we just have to reclaim land area.)

[kestrel91316]

11. Oh, yeah, because conditions on earth were just pefect for human civilization during the

Ordovician period.

[wtmusic]

28. Sweltering

An average temperature of 105°F vs 55°F today. Equatorial regions would suffer summer peak temperatures above the boiling point of water, and make timeshares in those areas rather unattractive investments.

[struggle4progress]

13. Whose site is it?

[bhikkhu]

17. Monte Hieb

he's talked about at this link a bit:

http://globalwarmingwatch.blogspot.com/2006/04/end-of-our-epoch-all-in-good-time-2.html

Apparently once an engineer for West Virginia's Office of Miner's Safety, now maybe a professional blogger.

[struggle4progress]

18. So we needn't take his climate theories too seriously

[bhikkhu]

20. No, apparently he's never had a piece go through peer review.

And probably never will. When your audience doesn't know what peer review is, there isn't really much point I guess. Still its good to know what kind of theories are floating around out there, and where they are lacking.

[Dead_Parrot]

16. It's also nice and cold

It's interesting to see the the spin being put on it: We're CO₂ impoverished! (and nevermind that it's 10°C colder because of it.)

Or rather, 15°C - He seems to have fluffed the temperature from scotese which runs from 10-25°C. Which is a shame, I've used the geocraft graphic before to show how close we are to replicating the Permian extinction.

[wtmusic]

23. "So far the signal of a discernible human contribution

to global climate change has not emerged from this natural variability or background noise."

Fail. Let's look at periods relevant to homo sapiens:

"The most direct method for measuring atmospheric carbon dioxide concentrations for periods before direct sampling is to measure bubbles of air (fluid or gas inclusions) trapped in the Antarctic or Greenland ice caps. The most widely accepted of such studies come from a variety of Antarctic cores and indicate that atmospheric CO2 levels were about 260 – 280 ppmv immediately before industrial emissions began and did not vary much from this level during the preceding 10,000 years (10 kyr)."

http://en.wikipedia.org/wiki/Carbon_dioxide_in_Earth%27s_atmosphere

"With the industrial era, human activities have at the same time increased the level of carbon dioxide (CO2) in the atmosphere, primarily through the burning of fossil fuels. Carbon dioxide is one of the main greenhouse gases, and scientists have been able to connect human activities as one of the drivers to climate change and global warming."



http://maps.grida.no/go/graphic/historical-trends-in-carbon-dioxide-concentrations-and-temperature-on-a-geological-and-recent-time-scale



http://en.wikipedia.org/wiki/Temperature_record_of_the_past_1000_years

[bhikkhu]

24. That's one argument that I think will get harder and harder to make

as you point out in graphs, the present anomaly is obvious to anyone not wearing ideological blinders.

[NYC_SKP]

25. That site, geocraft, is apparently in denial of anthropogenic climate change.

Per their online quiz, http://www.geocraft.com/WVFossils/GlobWarmTest/start.html

The "right: answer to Question 3:

The main cause of Global Warming is:

a) pollution from factories and automobiles
b) orbital eccentricities of Earth and variations in the Sun's output
c) the Greenhouse Effect

Is: "b) orbital eccentricities of Earth and variations in the Sun's output"

I think it's a very poorly worded question, because all of these are factors.

Then, they link to this obvious denial site: http://www.junkscience.com/

[NickB79]

27. I, for one, don't want to live in a Devonian/Carboniferous swamp

But that might just be me :shrug: