5.2.3 Explain the enhanced greenhouse effect

The greenhouse effect is a NATURAL PHENOMENON.

Incoming short wave radiation from the sun enters the atmosphere. Some of this is re-emitted from the earth's surface as longer wave radiation and results in heat lost to space. The rest is reflected from the earth and absorbed by greenhouse gases in the atmosphere (such as carbon dioxide, methane, oxides of nitrogen and water vapor). These then re-reflect the radiation back towards earth. This absorption of radiation by greenhouse gases results in heat being retained in the atmosphere and therefore the mean temperature of the atmosphere increases.

When the concentration of these greenhouse gases is increased, more radiation is absorbed by them and thus more heat is retained in the atmosphere. This results in a greater increase in mean temperature of the atmosphere, and this is known as the enhanced greenhouse effect.

[iCookieCrunch]

Thank you this is useful for my a level geography revision as I don’t understand the notes I have!!

[grindupBaker]

*** PART 3 OF 3 ***
The tropospheric temperature lapse rate is required to cause the so-called "enhanced greenhouse effect".
The average altitude for LWR to ocean and land got lower (1, 650 metres ---> 1, 550 metres in my example) which means LWR to the surface of the ocean and land is from warmer (faster) molecules on average because tropospheric temperature decreases with altitude and LWR to ocean/land is from lower-down-than-before molecules on average, so there are more GHG molecular collisions / second which leads to more MVE which leads to more LWR production. The quantity of LWR energy (power flux) provided by a mass of gas is proportional to its temperature(Kelvin)**4 (to the fourth power) so, as explained in detail above, the increasing of tropospheric GHGs ==must== cause more LWR than before to be passing downwards to the surface of the ocean and land. This latter is called "downwelling LWR radiation at the surface" and I've explained why it must increase and this must, of course, warm the land and ocean surface.
That's the lower end of how the so-called "enhanced greenhouse effect" works.

Note 1: I haven't yet found the collision MVE production & destruction spectra so I don't know what %age make MVE and what %age destroy MVE. I looked a few hours 4 years ago but couldn't find it (not for free anyway). It makes no difference to the description of the mechanism above but it would be needed to confirm the quantity of effect for doubling CO2.
Note 2: Removed because I've gotten confirmation.
Note 3: 80% of Earth's atmosphere is in the troposphere (the top of which is 16 km in the tropics and 9 km in the polar regions, averaging ~12, 000 metres). The "greenhouse effect" warming can only happen in Earth's troposphere, there's no effect in Earth's tropopause and the effect is "backwards" in Earth's stratosphere with =increased= stratospheric GHG gases causing =cooling= of the stratosphere because the stratospheric temperature lapse rate has temperature increasing with altitude (that's how it's known with total certainty that it's increased "greenhouse gases (GHGs)" doing the global warming for the last several decades). Since there's no temperature lapse rate in the tropopause then any change in the quantity/type of GHGs in the tropopause cannot have any warming or cooling effect on the tropopause or the entire atmosphere, ocean or land. No effect at all. If you follow my description of the effect above for the troposphere but apply it to the tropopause then you'll clearly see that any change in the quantity/type of GHGs in the tropopause cannot have any warming or cooling effect That's the reality. The increasing GHGs in the stratosphere are a slight -ve feedback to global warming because downwelling LWR radiation from the stratosphere decreases with increased GHGs, but it's a very slight -ve feedback because only 6.3% of the well-mixed GHGs (and all molecules) are above the tropopause and they are initially colder than the average of the troposphere so they make even less LWR than the 6.3% factor. By the time the stratosphere warms more than the average of the troposphere there's only 0.4% of Earth's atmosphere's molecules above, negligible.
Note 4: FTIR power flux vs wave-length spectra recorded by the IRIS Infra-Red Interferometer Spectrometer instruments on the Nimbus-1 (1964 - 1964), Nimbus-2 (1966 - 1969), Nimbus-3 (1969 - 1972) satellites show which wave-lengths of LWR heading to space past the satellite came from the surface of the ocean and land and which wave-lengths came, on average, from the GHG molecules and surfaces of solid particles and water droplets in the atmosphere. From this atmospheric physicists have calculated the 91.5% of the LWR that Earth sends to space that is emitted by the atmosphere rather than by the surface of the ocean and land. Also, the MODTRAN tool on the internet can be used to play with a theoretical calculation of the FTIR power flux vs wave-length spectra by adjusting GHGs.
Note 5: 2020-01-25 edited example altitudes. The Kevin Trenberth & other Earth's energy budgets show 17% (40 w/m**2) in the atmospheric window but "Outgoing Longwave Radiation due to Directly Transmitted Surface Emission" of S.M.S. COSTA & K. P. SHINE 2012 states that as ad hoc and assesses instead 8.5% (20 w/m**2 +/- 4 w/m**2). I don't attempt quantifying anything in the effect explanation but I made my examples for illustration as close to reality as is reasonable to do (Stefan-Boltzmann equation & average tropospheric temperature lapse rate).

[ripthelat]

Did you misplace 5.2.4 and 5.2.5? I dont see them in the playlist

[PacificCircle]

You forget the water vapor that is increased from irrigation.

[wrath]

The Earth is in thermal equilibrium at a temperature T, energy from radiation in equals energy from radiation out. The temperature is stable. You state that additional greenhouse gases reduce the energy leaving the Earth, so to an observer looks to be cooler. Clearly equilibrium needs to be restored as a body must increase in temperature until energy in equals energy out. The Earth needs to increase its radiation to more than before to make up the deficit due to some energy not escaping. This means the surface has to emit more radiation which requires more energy in. It goes against the laws of physics to claim the energy it has already emitted can be used again to achieve this. If you could reuse energy in this way, perpetual motion would be possible. Where does the additional energy come from?

[grindupBaker]

This video does not properly describe how the so-called "greenhouse effect" in Earth's troposphere causes warming because there is no description of the ABSOLUTELY VITAL role of the tropospheric temperature lapse rate. For a so-called "greenhouse effect" in a planet's atmosphere to affect surface temperature it absolutely requires TWO THINGS and not just ONE THING. It absolutely requires:
1) The type of gases with the "springy" covalent bonds that have energies matching those of frequencies of transverse electromagnetic radiation which the surface emits (the GHG molecule's "absorption spectrum"), and
2) An atmosphere with a temperature lapse rate in which atmospheric temperature decreases with altitude.

Here's why:
LWR EMISSION: The amount of long-wave radiation (LWR) that a "greenhouse gas (GHG)" emits depends on how often it collides because it can (and almost always does) obtain the harmonic motion in its "springy" covalent bonds by collision. So if it collides 3, 000, 000, 000 times / second then obviously it'll get a "ringing" of its oscillating atomic nucleus (carbon for CO2) more often than if it collides 2, 000, 000, 000 times / second (average for Earth's troposphere is 2, 700, 000, 000 collisions / second for a molecule). Since the collision rate depends on temperature because the molecules are flying around faster (that's precisely what "temperature" & "heat" are in a gas, the average speed/weight of molecules, in a liquid or solid its "jostling" rather than "flying around") therefore at higher temperature there will be more LWR photons generated because more collisions. A scientists named "Max Plank" figured this out and other scientists developed the Stefan-Boltzmann equation PF = 5.6703 * (temp<Kelvin>/100)**4 where "PF" is the power flux in w/m**2 for a bulk quantity of gas. Since temp<Kelvin> decreases on average by 6.75 degrees for each 1 km increase in altitude therefore the power flux emitted by the GHGs decreases strongly (as the 4th power) as the altitude of the GHGs increases.

LWR ABSORPTION: The amount of long-wave radiation (LWR) that a "greenhouse gas (GHG)" absorbs DOES NOT DEPEND IN THE SLIGHTEST on how often it collides so the amount of long-wave radiation (LWR) that a "greenhouse gas (GHG)" absorbs DOES NOT DEPEND IN THE SLIGHTEST on the temperature of the parcel of atmosphere that it is in.

The tiny portion of you who have functioning brains, as I do, will immediately realize that the combination of
1) LWR EMISSION strongly increases with air temperature (5.6703 * (temp<Kelvin>/100)**4), and
2) LWR ABSORPTION doesn't depend in the slightest on air temperature, and
3) The temperature of Earth's troposphere decreases with altitude
means that increased GHGs in Earth's troposphere (definitely not any higher though) MUST cause tropospheric warming because increased GHGs means the quantity is getting higher and that means cooler and, per above, that means less LWR emission per unit GHG quantity but no change in LWR absorption per unit GHG quantity, so exactly the same LWR as before from below gets absorbed but less LWR than before gets sent upwards (the direction in which some of it will get to space). Very simple little bit of basic physics. British 13 year old grammar school child level.

This is why there can be no so-called "greenhouse effect" in Earth's tropopause and the "greenhouse effect" works BACKWARDS in Earth's stratosphere (increased GHGs should cool the stratosphere as I've just explained, and they definitely are, it's being measured by satellite instrument). Since the video here doesn't describe the absolutely vital role that the tropospheric temperature lapse rate plays in the "greenhouse effect" therefore it is highly incorrect and can easily be debunked by any self-respecting coal/oil shill (though perhaps they don't exist) not at all because the "greenhouse effect" is invalid science but because THIS VIDEO ABSOLUTELY DOES NOT DESCRIBE THE PHYSICS OF THE SO-CALLED "GREENHOUSE EFFECT IN EARTH'S TROPOSPHERE".

[chanelchamaa]

lak dont worry they call me wiki leaks