What increase in temperature would be expected in a lab with increased CO2 levels.?

Question

Ok, so what temperature increase would you expect to see if a flask containing gases of the same concentration as the atmosphere if you increased CO2 concentration from 0.028% to 0.038%?

How controversial is this?

By the way, I don't want to hear about "feedback", I already know about that, I just wanted to know the predicted temperature rise if this was done in a laboratory.

Answer 1

Depends, is the flask in the sun?   CO2 doesn't create heat, it just stores it.   Probably not much since its such a small volume of gas; a milimeter of insulation on a small volume isn't going to have as much effect as 15 cm's insulation is going to have on a larger volume.

Answer 2

I don't know the answer, but it's interesting. Does any one know if scientists in the lab have ever tried to create a miniature biosphere of our earth including as many variables as humanly possible. It seems that if you could do that, you could answer a lot of questions.

Answer 3

That's actually a nice introductory chemistry experiment:

http://www.chemsoc.org/networks/learnnet...

I don't have the figures handy, but that increased CO2 concentrations will retain more heat isn't controversial at all.  You can read more about the history of this here:

http://www.aip.org/history/climate/co2.h...

Evans - Have you ever even taken an introductory chemistry course? It doesn't sound like it.  Perhaps you should consider insulation, albedo, and heating/cooling systems are the reason it's normally not hotter inside a building with higher CO2 levels than outside.

Answer 4

Many studies have been done regarding the Earth's sensitivity to increasing atmospheric CO2, the first one being over a century ago in 1896.  Most of them focus on how much the planet would warm if CO2 levels doubled from 280 ppm to 560 ppm.  A summary of their results is available here:

http://members.aol.com/bpl1960/ClimateSe...

If you scroll to the bottom of the page, you can see that the results are converging close to 3°C warming for a doubling of atmospheric CO2.

So for a 37% increase (280 ppm to 384 ppm), you would expect to see about a 1°C warming, which is approximately what we've experienced.

http://data.giss.nasa.gov/gistemp/graphs...

These studies weren't done in a laboratory setting because you can't simulate the highly complex climate of the Earth in a lab, as gcnp58 explains.

Answer 5

That's funny, because they can't reconstruct their abstract theories under laboratory settings...that's why AGW still exists at all.  

CO2 concentrations are usually higher indoors than the outside ambient air, yet the temperature is cooler.  Why?  The air is shaded from the sun.  Just more proof the sun causes global warming.

Go ahead and fill the room with 100% CO2....the temperature won't change if all other variables are controlled.

Edit:  LOL!!  I knew that would get someone's goat!  What's the matter Ken, scared I'm speaking at the public level?  Is it simple-minded enough to sway the masses?  Are you here to bathe us in your infinite wisdom?

Answer 6

The problem with that experiment is that it is extremely, ok, impossible, to create the same conditions in the laboratory that you find in the atmosphere.  The problem is one of scale, and that on kilometer and greater vertical scales, the atmosphere is not homogeneous.  Laboratory scale experiments, with scales on the order of a few tens of meters at most, will always have homogeneous gas phases.  

The inhomogeneity in the atmosphere is due to the combination of the adiabatic lapse rate, which makes the air colder the higher you go (up to the stratosphere) and the fact that at normal surface temperatures, water is found in a liquid state.  That last part is critical because it means that the thermodynamic equilibrium partial pressure of water in the gas phase is not determined by the ideal gas law, but by temperature and the vapor pressure of liquid water (or vapor pressure of ice once the temperature drops below 273.15 K).    Therefore, the mixing ratio of water vapor decreases with altitude whereas the mixing ratio for all other atmospheric gases (including CO2) is constant up to the homopause.  

The result of all this is that when you model radiative transfer through the real atmosphere, water vapor has a large effect for altitudes below about 5 km and the absorbance of longwave infrared radiation is essentially saturated.  At these low altitudes, increasing CO2 has little effect on radiative transfer.  However, above 5 km, the air is very much drier, because of the effect I explained above, the air is colder, the vapor pressure of water/ice is lower, and the mixing ratio of water has dropped off.  This means that the longwave IR absorbance is not saturated and that increases in CO2 will have an effect on radiative transfer and lead to a forcing.  

It is extremely difficult to simulate this effect in the laboratory since you can't get a large temperature gradient (or alternatively a pressure gradient) to be stable with time.  Because of that, you can't generate an inhomogeneous gas phase with respect to a single component.  So while you can show that increasing CO2 concentrations leads to increasing IR absorbance, demonstrating the "greenhouse effect" via radiative transfer is not possible.  

Most "greenhouse effect" demonstrations you find on the web that show warming with an increased CO2 atmosphere are in fact demonstrations of the actual greenhouse mechanism, suppression of convective cooling, rather than increases in radiative forcing (i.e., the atmospheric greenhouse effect).  

So researchers have shown ad infinitum that CO2 absorbs infrared radiation.  They also have measured H2O and CO2 through the troposphere.  Chandrasekhar worked out the theory for radiative transfer through inhomogeneous atmospheres in the early 50's.  Putting those pieces together in models leads to the conclusion that increasing CO2 from 280 ppm to 380 ppm (or thereabouts) leads to an increase in the planetary longwave radiative forcing of about 1.6 W/m^2.  That this same theory explains the surface temperature of Venus and Earth when not forced by increasing CO2 levels is pretty strong evidence it is correct.  

But you can't simulate this in a laboratory because of the scale effects.  There are lots of things you can't effectively simulate in a laboratory, plate tectonics for instance, that doesn't make them wrong.