Now we can calculate how much energy it would require to raise the temperature of the troposphere by a single degree Kelvin:
1.012 J/g·°K = 1.012 kJ/kg·°K
1.012 kJ/kg·°K · 1.2 kg/m³ = 1.2144 kJ/m³·°K
1.2144 kJ/m³·°K = 1,214,400,000 kJ/km³·°K
The re-transmitted 50% will then be once again emitted by the earth and 50% of that which is absorbed by greenhouse gases will be transmitted back down to the earth. This will happen over and over with the proportion of the total initial energy decreasing down to nothing (think two mirrors opposite each other with 50% attenuation).
Originally posted by neo5842
This is what we need, though in my simple understanding of the mathematics here, i would like to see, how sunspots would change things when added to the equation, though i understand its not possible to see with any degree of accuracy because of how random they can be from year to year, though i do understand the 11, 80 (and so on) year cycle, but still not predictable. As far as i am aware they contribute the largest amount of energy attributed to the heating and cooling of the planet, and for that reason it can take up to 800 years for the CO2 to follow with its increase. Leading to many to conclude that the earth is in a state of cooling rather than warming as a result of the sun's relative inactivity for the past 9 years or so. Please correct me if i am wrong. However like i said i would like to see how things look after sun spots are taken into consideration.
Originally posted by downisreallyup
reply to post by DjSharperimage
Also, CO reforms into CO2 in the air, only remaining in the air for a relatively short time (couple months).
Originally posted by DjSharperimage
Originally posted by neo5842
This is what we need, though in my simple understanding of the mathematics here, i would like to see, how sunspots would change things when added to the equation, though i understand its not possible to see with any degree of accuracy because of how random they can be from year to year, though i do understand the 11, 80 (and so on) year cycle, but still not predictable. As far as i am aware they contribute the largest amount of energy attributed to the heating and cooling of the planet, and for that reason it can take up to 800 years for the CO2 to follow with its increase. Leading to many to conclude that the earth is in a state of cooling rather than warming as a result of the sun's relative inactivity for the past 9 years or so. Please correct me if i am wrong. However like i said i would like to see how things look after sun spots are taken into consideration.
IT IS NOT CARBON DIOXIDE (CO2)
IT IS CARBON MONOXIDE (CO) !!!!!!
will you people please!!!!! learn your table of elements!!@!!!!!
Originally posted by 4nsicphd
Oh-Oh. a concepual problem - the sort my physics students have when they haven't studiedfor the final . You multiply Radiant energy times the % increase in CO2 per Wikipedia. That's a big fail. It's like painting a 150 mm thick window with5mm of black paint and saying it's only going to cut down on 3% of the light coming in. It ignores totally the absorption spectrum of the substance. Think about it. The sun warms one=half of the earth 's atmosphere by 15 degrees K in 4 months every spring and summer.
Your post is going to be a good exercise for my class this weekend. I'll let them dissect the wikipedia references and double check the caculations.
Offhand, it appears that you have used a specific heat value for fresh water. That is enough to get you a reject from a refereed journal. You need to use the correct value for the correct salinity. And specific heat also varies with pressure. What Q are you using? ISA? And what values for the albedo from all surfaces?
Yor approach is actually conceptually correct for the first part of the problem = find out the total rnergy budget. But it's only a start. Next look at absorption spectra The absorption spectra must be applied And the specific heat and relevant albedos. Then you look atthe real world and see if it fits your model.
i'm afraid your work is not quite ready for prime time. Or a refereed journal. But keep working. I like the effort.But before your next effort you should study the concept of significant figures and computational accuracy. 8,694,154 km, huh. How sure are you that it's not 8,694,153 or 8,694,155? There is a difference between precision and accuracy. To the layman, the purported exactness seems impressive. To a scientist, it screams poseur. I'm not going to tell my class where this little homework exercise in critical analysis came from. Unless you want me to.
EYou should see some of the crackpot stuff we get at the journals for which I review. Yours is not crackpot, just fatally flawed. For now. Keep working, tho.
I still don't get why you decided to add the ocean... Why not do the ground as well?
Water vapor is the most significant, but you can't stop that from happening right?
I still don't get why you multiplied the amount of energy that reaches the sun by 0.01% which is the increase in CO2 levels.
What does that give you? It doesn't give you the amount of light trapped by CO2.
Originally posted by TheRedneck
It has been theorized that the use of anthropogenic (man-made) carbon dioxide is the reason for the recently observed warming trend from ca. 1960-1998. The present level of CO2 in the troposphere is stated by multiple sources as being on the order of 380 ppmv. This represents an increase, based on the most liberal estimates I have uncovered for pre-industrial levels of 280 ppmv, of 100 ppmv or 0.01%. Since this base point is considered to be 'safe and natural', it would logically follow that any warming would have to be associated with the 0.01% increase and it alone.
All heat energy reaching the earth is from the sun, in the form of solar irradiance. Heat reflected back into space is a result of this solar irradiance, and can therefore be considered the same in energy calculations.
Solar irradiance can and has been quantified. The amount of energy reaching the planet is on the order of 1366 W/m². The planet presents a more or less circular profile to the sun, so the area of the earth normal to solar irradiance can be calculated as this circle. The earth is an average of 6371 km, with a troposphere layer surrounding it that averages 17km in height, which also must be included since it is the location of the atmospheric carbon dioxide.
again you forget to correctly unit your statistic in volume, so now you have an inaccurate and debatable value that is not given in the proper units. You need to be dealing with joules per kilogram or per meters squared and then per second. Atmospheric energy is unitized in j/kg, or j/m^3.
That result is in Joules (or kiloJoules) per second. Since most climate predictions are based on much longer time intervals, I will now calculate how much energy would be available during such a longer time interval such as the commonly used 100-yr. period:
100 yr = 36,525 days = 876,600 hr. = 52,596,000 minutes = 3,155,760,000 s
We can now multiply this time interval by the rate of energy influx to obtain the total energy that the planet will receive from solar irradiation over the next 100 years:
175,117,838,274,000 kJ/s • 3,155,760,000 s/100yr =
552,629,869,311,558,240,000,000 kJ/100yr
you are now assuming a homogenous atmosphere with a homogenous ppm for co2. this is not the case. Co2 levels vary, and greatly, depending on where in the globe you are. And then you have to take into consideration how much energy that part of the globe is receiving, what the surface coverage type is and its albedo, then find out the average amount of water vapor is available and the average height of the tropopause and the average volume of the column of atmosphere you are looking into. You cannot simplify such a complicated process!
Now we must calculate exactly how much of that energy will be affected by the increase in the amount of carbon dioxide in the troposphere. Remembering that the increase from pre-industrial levels is 0.01% of total atmospheric volume, we multiple this total energy by 0.0001:
552,629,869,311,558,240,000,000 kJ/100yr • 0.0001 =
55,262,986,931,155,824,000 kJ/100yr intercepted by anthropogenic CO2
Now let us turn to the question of how much energy is needed to increase global temperatures. Of course, the first and most obvious area to be heated is the troposphere itself.
again, not area… but volume. The volume of the troposphere is what you calculated, but that still does not take into effect that the troposphere is denser at the poles, despite being a thinner layer there.
Air under average atmospheric conditions has a specific heat capacity of 1.012 J/g•°K and an average density of 1.2 kg/m³. The troposphere itself can be calculated by using the information presented earlier (average radius of earth = 6371 km and a troposphere extending 17 km above the surface). Thus the area of the troposphere can be determined by calculating the volume of a sphere of 6388 km radius and subtracting a sphere of 6371 km radius from it:
V(tot) = 4/3 π r³ = 4/3 π • 6388³ = 1,091,901,171 km³
V(earth) = 4/3 π r³ = 4/3 π • 6371³ = 1,083,206,917 km³
V = V(tot) - V(earth) = 1,091,901,171 km³ - 1,083,206,917 km³
= 8,694,154 km³
Now we can calculate how much energy it would require to raise the temperature of the troposphere by a single degree Kelvin:
[align=center]1.012 J/g•°K = 1.012 kJ/kg•°K
1.012 kJ/kg•°K • 1.2 kg/m³ = 1.2144 kJ/m³•°K
1.2144 kJ/m³•°K = 1,214,400,000 kJ/km³•°K
You are assuming a constant density of 1.2 kg/m^3 for the atmosphere up to 17 km. This is entirely incorrect.
Also the atmosphere extends out to roughly 60 km
Then again, this is assuming that all intercepted energy affects only CO2, which is very conservative. To do this properly, you need to use the absorptivities (throughout the optical spectrum) of CO2, and all other greenhouse gases to find heat input for each greenhouse gas.
Integrate over the absorption spectrum/irradiant solar energy like this:
And what I am proposing is a simple analysis compared to climate models out there.
Basically what it comes down to is that this is not a problem well suited to back of the envelope calculation at all. This is not an engineering problem where you can assume certain things to make the problem easier and have it come out to anywhere near the correct answer. It is far too nonlinear, and there are far more variables than you have specified.
I applaud your use of math and physics on ATS, certainly ATS could stand some more rationality now and then. But, you have to remember to make sure your assumptions are reasonable, and that your math makes sense. Cheers.
Originally posted by TheRedneck
reply to post by ZombieOctopus
That's your rebuttal?
"They've got bigger computers and they're smarter"?
Come on, at least try to rebut the calcs. Just saying "I don't believe it" isn't much of a rebuttal...
TheRedneck
Originally posted by Hastobemoretolife
reply to post by ZombieOctopus
That is IF the models are programmed right, and all the data is correct. If the model is coded incorrectly and the data is wrong, then it could be a quadrillion core super computer and it's still going to get it wrong.
Computers are only as correct as the people programming them. As I also mentioned earlier they don't know the effect of clouds on the environment so before they can eve think of getting a correct model coded they need to know if the clouds produce a negative or positive feedback.
As I also mentioned if clouds produce a negative feedback then that means the climate is negative feedback, which means it doesn't matter what we put into the environment the earth will right it self.