ooh boy... first let me say that i am not disagreeing with your conclusions, as i am a proponent that the earth is warming outside of human and
industrial influence. the issue that i have here is some flaws in your thinking and such that i would like to point out to help strengthen your case
and remove holes.
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.
ok sounds good so far, although i am not sure where the 0.01% is coming from. is this a ratio to the whole volume of the troposphere or a ratio of
initial ppmv to current ppmv, which would be an increase of nearly 36%. be clear here what you are saying.
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.
Again, this is not entirely true. You have to talk about the interaction with the solar radiation and the earth/atmosphere. a large portion of the
suns energy is actually filtered in the thermosphere. The earth is considered to be a black body, and for all intensive purposes will emit all of the
energy that is absorbed. The heating is due to the absorption of the shorter wave energies coming in and the emitting of the longer wave terrestrial
radiation. It is the longer wave energy that is emitted that is absorbed by the atmosphere which is NOT a black body and has absorption windows cause
them to trap certain wavelengths.
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.
Woah woah! Slow down! Important note here! You are calculating for a flat disk. Not to mention you are not taking into consideration the VOLUME of the
troposphere, or the atmosphere’s above it. The earth is a spherical shape, and the angle of incidence of incoming solar radiation has a HUGE impact
on the amount of absorbed solar radiation. Why do you think it can be daylight for 6 months at the poles and be cold as all get out? Any figure that
you propose to be the quantified amount of solar energy that is absorbed by the earth at this point is about as accurate as me throwing a dart at a
board blind folded and dizzy! It is not as simple as you try to make it seem.
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
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.
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
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 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.
There are multiple layers of the troposphere and each one is heated differently. For instance the molecular boundary layer (that being the point where
the air “touches” the ground, is heated through convection, while the planetary boundary layer is heated mostly by mixing (that is the “dirty”
layer that interacts with all the terrain and what not) and the free atmosphere is heated through radiation. Each process requires different
circumstances and cannot be married so simply as you state.
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
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.
While I give you a star and flag for effort and overall importance of the message, there as you can see many many holes that under scientific scrutiny
would be torn to shreds.
Regards-
Wx4cAsTeR