Atmospheric evolution of the Earth

I hope someone can explain this to me. 3.5 billion years ago Carbon Dioxide levels were thousands of times higher than they are today. But yet Earth didn’t turn into Venus. I do believe in global warming due to CO2, but I am not sure I buy some of the more extreme claims predicted by some people. So in order to get some perspective I’m asking the question. How much global warming did we have when the carbon dioxide in the atmosphere was 350,000 PPM and why should we be freaking out over 400 PPM?

  1. bobbo, are we Men of Science, or Devo says:

    Hey Marc—-just for grins====BECAUSE, I do admire your libertarian stance…… and your squirrel.

    If you have remaining questions that maybe tossing the ball back and forth could provide some insights…..drop me an email…..or answer here. I will follow this thread for a time to gauge any continuing interest on your part.

    Your words notwithstanding, I sense you are anti-AGW “in final analysis/reality.” I’ll even say: make it a three way. Mickey is anti AGW BUT==also well informed. By well, I mean he does have a lot of the mechanics and details/science down….then he fubars when it comes to drawing a common sense/scientific conclusion. THAT is interesting too!

    How do we know what we know, and how do we change our mind?……….Endlessly fascinating to me. I DO have my mind around it….from time to time….issue by issue. Comes and goes actually!! :-)

    • IM75 says:

      Impressed (certainly more lately than I used to be.) Not that it matters.

  2. Captain Obvious says:

    I’m trying to figure out at what point did this thread cross the event horizon and couldn’t escape the crushing oblivion of the bobbo black hole.

  3. MikeN says:

    Fess up, Mark Perkel. This post of yours was the result of a Trading Places style bet. You got Bobbo to post half the responses.
    So who is Valentine?

    • bobbo, are we Men of Science, or Devo says:

      YOU KNOW….the flip side of the complaint that I post too much is: why aren’t you guys posting more?

      On the OP, I totally understand the kind of ambiguity that presents when you first read that co2 causes atmosphere to heat up and then that Earth had lots of co2 and did not heat up. Sounds like a contradiction…but it completely demonstrates a real weakness of innate human reasoning that we all must become aware of: treating complicated multi factored issues as if there was but one variable. Recognize this trait/tendency and many more issues become almost immediately less contradictory: there are other issues that give us the outcome. Try it. I laugh at myself when I notice I’m doing it. Course, I do it less which gives me more time to be confused by my other failings.


  4. MikeN says:

    Small list of errors by one prominent climate scientist.

    • bobbo, are we Men of Science, or Devo says:

      Hey Mickey.

      Religious/conservative mind set: resistant to change, uncomfortable with ambiguity, seeks simple absolute explanations.

      Scientific/humanist mind set: seeks change/new ideas, looks for the ambiguity, and distrusts simple absolute explanations.

      Forarmed as you are now….how should the “theory”/understanding of AGW go forward? Absolute and correct right out of the gate with not a single authority world wide ever getting anything wrong….or like EVERY OTHER FREAKING THING WE KNOW IN THE UNIVERSE==>by hits and misses that narrow down to what is generally accepted?


      #2–So Mickey==another conservative mind set: never deal with questions that undermine what you already think. Does Venus demonstrate the effect of co2 loading in an atmosphere or not? How does it apply to Earth’s atmosphere? ie==much or hardly at all?

      Take a breath, THEN……GO===========>

      Ha, ha. Oh Mickey, why do I like you so much?

    • bobbo, are we Men of Science, or Devo says:

      Nice link to read though. I don’t know the science well enough to parse it on first look. On its face, it sure looks like Mann is incompetent if not fraudulent.

      If that dense cloud cover on Venus just made it cooler than Earth…..wouldn’t that meet Marc’s skepticism et al?

      AGW==a good issue re Man vs Devo. How do you make up your mind, and how do you change it?

      I accept the general consensus of scientists that evolution proceeds pretty much as Darwin first published and that co2 is a Green House gas that if not curtailed will poisonous us all.

      After that, its all dithering details.

      • Tim says:


        • bobbo, are we Men of Science, or Devo says:

          I agree. So succinct you are Timmy. A real pleasure to read.

          What we need is fag hating HMyers to kick our asses all over the place with his most informed opinion.

          I love it when that happens.

      • deowll says:

        Venus has a surface pressure of 90 bars. That is 90 times what earth has. It also gets 3 times as much solar energy as Earth. It also seems to rotate on its axis about once a year according the last study I read but they used to say it was tidally locked on the sun.

        You might want to look at this:

        Please not that the air you breathe out contains between 35,000 and 50,000 ppm of CO2. Indoor air at 5,000 ppm makes you groggy.

    • Captain Obvious says:

      I guess all the guys who can’t post on reddit science forum come here now.

  5. pedro says:

    Could someone please give bobbo his medicine? Thank you!

  6. Bookshelf says:

    400-500 PPM and you die. after 3 hours

  7. deowll says:

    I did a little research and CO2 is nothing like as powerful as water vapor as a green house gas because it only directly impacts a tiny part of the spectrum. Reality is that if you double the amount of CO2 in the atmosphere, in theory, you just might get 2C of warming and another doubling would do the same etc. but that also assumes air doesn’t move and it does. AGW was supposed to work by causing more water vapor to be in the air but satellite data shows that isn’t happening. That should have ended it.

  8. Harris says:

    The reason Earth’s surface temp has been relatively stable (with the exception of some ice ages) despite the huge drop in atmospheric CO2 over time all has to due with the Sun. Back when the Sun was 4 Billion years younger it was significantly dimmer and put out a lot less energy.
    However, there was a far higher level of greenhouse gases in Earth’s atmosphere at the time which compensated for the lack of solar radiation.
    Over time the Sun’s output steadily increased (like all good yellow dwarfs do) and if the amount of greenhouse gases in Earth’s atmosphere remained constant Earth would indeed have ended up looking like Venus.
    Luckily for us, and all other forms of life here, the amount of CO2 and various other greenhouse gasses began to drop. What caused this drop? The main cause has been the sea life such as foraminifera and coccoliths which pull CO2 out of the water (which pulls CO2 out of the air) in order to make their tiny shells. When they die, depending on the local ocean temperature and chemistry, they fall to the bottom and become limestone. Sometimes the limestone gets dissolved through various mechanisms but most of the time it just sits there.

    So to sum up, we did have way more atmospheric CO2 contributing to the greenhouse effect 3.5 Billion years ago but it didn’t make the Earth much hotter than it is now because the Sun was weaker then. Since that time the rate of decline in the % of CO2 has been, more-or-less, matched by the rate of increase in solar output. If we start to increase the amount of CO2 in the atmosphere without a significant rise in temperature we need to find a way to reduce the amount of solar radiation that hits Earth.