5 ms·

How do we know CO2 is causing Global Warming?

15 points by philipn 17y ago

Folks, also see the graph of CO2 in the atmosphere over time: http://mathburritos.org/Atmos-CO2.gif

teeja 17y ago
Perfect example of the kind of straight-forward writing that is needed to help people to help people understand what's going on. It'd be great to see writing like this used to explain evolution clearly. (It may exist, certainly should exist, but I've never seen it.)
- thaumaturgy 17y ago
  I was all set to get all indignant and bombard you with links to PZ Meyers and the like, when I realized that you're right. The wonderful thing about this site is that it does such a great job of rounding up all the various global warming denialism and answers it factually and straightforwardly, without an excess of opinion or diatribe. Even after searching for a bit, I couldn't find anything like that for evolution. There are always books, though.
bumblebird 17y ago
Doesn't seem like a water tight argument at all to me. How about the alternate theory that heating up causes CO2 to be released from the Ocean - the extra CO2 is not the cause of heating, but the result of it. Way too much energy is being spent on this. Far more imminent threats to peoples lives and freedoms.
- thaumaturgy 17y ago
  It took only the merest effort to find this: http://skepticalscience.com/co2-lags-temperature.htm http://skepticalscience.com/co2-lags-temperature.htm You are right though that there are "far more imminent threats to peoples lives and freedoms". I would place willful ignorance to be chief among those threats. (See also http://scienceblogs.com/pharyngula/2006/01/idiot_america.php http://scienceblogs.com/pharyngula/2006/01/idiot_america.php)
  - bumblebird 17y ago
    I was talking about threats that actually kill people day to day. If I'm ignorant about the finer points of green house effects, it's not really that big a deal to my life, or that of my children. Perhaps every generation has to have a "catastrophe is just around the corner". I remember being taught at school how we'd run out of oil, coal, etc by the year 2000.
    - lawn 17y ago
      What if it turns out it'll kill 90% of all humans in say a hundred years? And what if we could have saved everyone if we just wasn't so ignorant? Now it doesn't really matter if you and I are ignorant, but if everyone is then that's potentially disastrous. You could draw similarities to medicine I think. What if nobody would've taken the first seemingly unnecessary steps towards creating the first vaccine, the first medicine etc etc. Where would be now? Sure there would be more acute things for these first "doctors" to do, but thanks to them we've now saved countless of people.
      - bumblebird 17y ago
        I find it extremely far fetched that if it was that imminent (Next 100 years), that there's anything we could do to prevent it.
        lawn 17y ago
        You're missing the point. In our little what if scenario, the point isn't how long it would take, but that it would happen and we had the power to prevent it.
        bumblebird 17y ago
        How are we going to prevent it?
        lawn 17y ago
- Tuna-Fish 17y ago
  > In 1970, NASA launched the IRIS satellite that measured infrared spectra between 400 cm-1 to 1600 cm-1. In 1996, the Japanese Space Agency launched the IMG satellite which recorded similar observations. Harries 2001 compared both sets of data to discern any changes in outgoing radiation over the 26 year period. The resultant change in outgoing radiation was as follows: > What they found was a drop in outgoing radiation at the wavelength bands that greenhouse gases such as CO2 and methane (CH4) absorb energy. The change in outgoing radiation over CO2 bands was consistent with theoretical expectations. Thus the paper found "direct experimental evidence for a significant increase in the Earth's greenhouse effect". Direct experimental evidence. Good enough for ya?
  - bumblebird 17y ago
    No, I can imagine there being many reasons for that (I'm no expert, but you have to admit there's quite a leap there between what was observed, and the explanation).
    - Tuna-Fish 17y ago
      Actually, as a physicist, I see no leap there. We know the absorption spectra of CO2. We measure an increase in the CO2 in the atmosphere. We measure the how well light penetrates the atmosphere, and we find it does so less well at the wavelengths that CO2 absorbs. At this point, we have a simple theory that is well supported by direct experimental evidence. What more do you need?
      - bumblebird 17y ago
        Well for a start, you need to know absolute numbers. Are the numbers big enough to make a difference.
    - dejb 17y ago
      It is nearly always possible to imagine alternative explanations for observations in complex systems. Sometimes the only way have any high level of confidence in a theory is to spend years studying the area and then more years researching the specifics of the particular theory. If you have a passion for this area then why don't you go down this path. Otherwise, like most people, you will often have to resign yourself to relying on the opinions of 'experts'. Choose your 'experts' wisely.
- yummyfajitas 17y ago
  The fact that CO2 is emitted from the oceans as they warm may explain long term trends in temperature. It would not explain short term trends in radiative transfer, or laboratory measurements of CO2's absorption spectrum. Note that you could write the exact same article replacing "CO2" with "H2O", though you might need to cite slightly different papers.
deleted 17y ago
[deleted]
yummyfajitas 17y ago
This article provides strong evidence for a minor and mostly undisputed point. This also proves almost nothing with regards to anthropogenic global warming, since I could write an identical article about H2O (maybe I'd need to tweak some citations).
- thaumaturgy 17y ago
  A treasure chest of answers has just been gathered up for you, the result of efforts of many other people. And it has been opened for you. And your attention has been diverted to it, briefly. And in that brief moment, you've noticed only one gem, found it not to your liking, and you've walked away, safe and comfortable in your belief that there is no such thing as a chest full of treasure. Try clicking some links on the site.
  - yummyfajitas 17y ago
    I clicked a link on HN. I noticed the article didn't live up to the title. I wrote a comment indicating this. Now it's my job to read other articles on the site (perhaps also misleadingly titled) to try to find evidence for the theory the original article hinted at in the title, but not in the body?
DanielBMarkham 17y ago
This is great. So line up the radiation measurements against temperature reports and you close the loop. ie, begin to form some sort of hypothesis about radiation and temperature.

15 points by philipn 17y ago

Folks, also see the graph of CO2 in the atmosphere over time: http://mathburritos.org/Atmos-CO2.gif

teeja 17y ago

Perfect example of the kind of straight-forward writing that is needed to help people to help people understand what's going on. It'd be great to see writing like this used to explain evolution clearly. (It may exist, certainly should exist, but I've never seen it.)

thaumaturgy 17y ago
I was all set to get all indignant and bombard you with links to PZ Meyers and the like, when I realized that you're right. The wonderful thing about this site is that it does such a great job of rounding up all the various global warming denialism and answers it factually and straightforwardly, without an excess of opinion or diatribe. Even after searching for a bit, I couldn't find anything like that for evolution. There are always books, though.

bumblebird 17y ago

Doesn't seem like a water tight argument at all to me. How about the alternate theory that heating up causes CO2 to be released from the Ocean - the extra CO2 is not the cause of heating, but the result of it. Way too much energy is being spent on this. Far more imminent threats to peoples lives and freedoms.

thaumaturgy 17y ago
It took only the merest effort to find this: http://skepticalscience.com/co2-lags-temperature.htm http://skepticalscience.com/co2-lags-temperature.htm You are right though that there are "far more imminent threats to peoples lives and freedoms". I would place willful ignorance to be chief among those threats. (See also http://scienceblogs.com/pharyngula/2006/01/idiot_america.php http://scienceblogs.com/pharyngula/2006/01/idiot_america.php)
- bumblebird 17y ago
  I was talking about threats that actually kill people day to day. If I'm ignorant about the finer points of green house effects, it's not really that big a deal to my life, or that of my children. Perhaps every generation has to have a "catastrophe is just around the corner". I remember being taught at school how we'd run out of oil, coal, etc by the year 2000.
  - lawn 17y ago
    What if it turns out it'll kill 90% of all humans in say a hundred years? And what if we could have saved everyone if we just wasn't so ignorant? Now it doesn't really matter if you and I are ignorant, but if everyone is then that's potentially disastrous. You could draw similarities to medicine I think. What if nobody would've taken the first seemingly unnecessary steps towards creating the first vaccine, the first medicine etc etc. Where would be now? Sure there would be more acute things for these first "doctors" to do, but thanks to them we've now saved countless of people.
    - bumblebird 17y ago
      I find it extremely far fetched that if it was that imminent (Next 100 years), that there's anything we could do to prevent it.
      - lawn 17y ago
        You're missing the point. In our little what if scenario, the point isn't how long it would take, but that it would happen and we had the power to prevent it.
        bumblebird 17y ago
        How are we going to prevent it?
        lawn 17y ago
Tuna-Fish 17y ago
> In 1970, NASA launched the IRIS satellite that measured infrared spectra between 400 cm-1 to 1600 cm-1. In 1996, the Japanese Space Agency launched the IMG satellite which recorded similar observations. Harries 2001 compared both sets of data to discern any changes in outgoing radiation over the 26 year period. The resultant change in outgoing radiation was as follows: > What they found was a drop in outgoing radiation at the wavelength bands that greenhouse gases such as CO2 and methane (CH4) absorb energy. The change in outgoing radiation over CO2 bands was consistent with theoretical expectations. Thus the paper found "direct experimental evidence for a significant increase in the Earth's greenhouse effect". Direct experimental evidence. Good enough for ya?
- bumblebird 17y ago
  No, I can imagine there being many reasons for that (I'm no expert, but you have to admit there's quite a leap there between what was observed, and the explanation).
  - Tuna-Fish 17y ago
    Actually, as a physicist, I see no leap there. We know the absorption spectra of CO2. We measure an increase in the CO2 in the atmosphere. We measure the how well light penetrates the atmosphere, and we find it does so less well at the wavelengths that CO2 absorbs. At this point, we have a simple theory that is well supported by direct experimental evidence. What more do you need?
    - bumblebird 17y ago
      Well for a start, you need to know absolute numbers. Are the numbers big enough to make a difference.
  - dejb 17y ago
    It is nearly always possible to imagine alternative explanations for observations in complex systems. Sometimes the only way have any high level of confidence in a theory is to spend years studying the area and then more years researching the specifics of the particular theory. If you have a passion for this area then why don't you go down this path. Otherwise, like most people, you will often have to resign yourself to relying on the opinions of 'experts'. Choose your 'experts' wisely.
yummyfajitas 17y ago
The fact that CO2 is emitted from the oceans as they warm may explain long term trends in temperature. It would not explain short term trends in radiative transfer, or laboratory measurements of CO2's absorption spectrum. Note that you could write the exact same article replacing "CO2" with "H2O", though you might need to cite slightly different papers.

deleted 17y ago

[deleted]

yummyfajitas 17y ago

This article provides strong evidence for a minor and mostly undisputed point. This also proves almost nothing with regards to anthropogenic global warming, since I could write an identical article about H2O (maybe I'd need to tweak some citations).

thaumaturgy 17y ago
A treasure chest of answers has just been gathered up for you, the result of efforts of many other people. And it has been opened for you. And your attention has been diverted to it, briefly. And in that brief moment, you've noticed only one gem, found it not to your liking, and you've walked away, safe and comfortable in your belief that there is no such thing as a chest full of treasure. Try clicking some links on the site.
- yummyfajitas 17y ago
  I clicked a link on HN. I noticed the article didn't live up to the title. I wrote a comment indicating this. Now it's my job to read other articles on the site (perhaps also misleadingly titled) to try to find evidence for the theory the original article hinted at in the title, but not in the body?

DanielBMarkham 17y ago

This is great. So line up the radiation measurements against temperature reports and you close the loop. ie, begin to form some sort of hypothesis about radiation and temperature.