26

The reason the atmosphere (including GHGs) stays attached to the earth is gravity. This is called the Hydrostatic Equilibrium. There is one GHG that this does not fully apply to: water vapor. While water vapor can be considered to be in hydrostatic balance, the fact that it undergoes a phase change (and becomes dissociated if it reaches too far up) prevents ...


14

Trapping compounds and changing composition are two very different things. The composition of an atmosphere is set by equilibrium chemistry. Equilibrium chemistry can be understood as mapping of a set of input atoms into molecules and remaining atoms. For example, at the given numbers of N, O, C, H... and given temperature and pressure, one will always find ...


6

You are correct that normally you see a net positive value of GHGs from land use change. However, if forests are grown or revegetated, it is considered a sink (and negative GHG value). This paper says that China has undergone a net increase in forest. The results sections says: The land-use data derived from Landsat Thematic Mapper (TM) imagery from 1990 ...


4

Δ𝐸=133.26+0.044[𝐶𝑂2] It’s just a numerical coincidence that the 0.044 looks like the molar mass of CO2. That equation gives 0.044 * 380 = 16 W/m2, which is the reduction in surface downwelling IR if you remove all the CO2 from the present day atmosphere (e.g., see Table 1 of Zhong and Haigh, 2013, Weather, https://doi.org/10.1002/wea.2072, pdf). Looking ...


3

Carbon dioxide has the same components as an oxygen molecule, plus a carbon atom, so the forces that keep oxygen from escaping the atmosphere apply even more to CO$_2$. The escape velocity of the Earth is about 11 km/s, and the speed of sound is 300 m/s. So a molecule would have to be traveling at more than Mach 30 to have escape velocity. That's not a ...


3

What you are looking for is called a zero-dimensional climate model. The equation without the Greenhouse effect is simple, though with a lot of simplifications, one with a very crude, linearized, Greenhouse effect is possible.


2

Looking at other planets in the solar system is a good way to get an indication of the role extreme variations of CO2 has. Mercury is closest to the sun, and has a high maximum temperature (449 centigrade) but a very low minimum (-170 centigrade). It has practically no atmosphere, and virtually no CO2. Venus, on the other hand - the planet between the Earth ...


2

There are other greenhouse gasses besides carbon dioxide (in particular water vapor) but in order to give a definite answer, let's pretend the atmosphere is completely free of them. In this case, it's easy to calculate the average temperature of the earth by holding the incoming shortwave heat flux at its present value and assuming that it is balanced by ...


2

The concentration of CO2 in the Earth's atmosphere has remained less than 1% in the past 470 million years when land plants first appeared--long before mammals, and long before humans graced the earth. If we are talking about having a biosphere comparable to the one we know, we need to be talking about CO2 and global average temperatures that are comparable ...


2

When you say produced, do you mean chemically made from another substance, or you do mean released into the atmosphere, or do you mean captured and stored? Methane, or CH4, is a biogas as it is gas biologically created by organisms. Methane is created in natural processes from which it may be immediately released into the atmosphere or on much slower time ...


2

Carbon dioxide is heavier than air but is found in nearly equal proportions throughout the well-mixed portion of the atmosphere. Xenon is much heavier than air, almost as heavy as sulfur hexaflouride, but it too is found in nearly equal proportions throughout the well-mixed portion of the atmosphere. Turbulence is what makes the well-mixed portion of the ...


1

We'll take an example of Venus as a poster child for runaway greenhouse effect. First of all, let's talk of day/night changes. At the surface level there is little to no change as Venus has an albedo of 0.77, i.e. its atmosphere reflects back 77% of light. Compare this to Earth's albedo of 0.3. So in the overall energy balance of Venusian atmosphere the ...


1

Do the calculation for 1 mol of CO$_2$ 1 mol of CO$_2$ weighs 49 grammes = 0.0049 kg 86400 seconds in a day, so 864000 * 0.0049 = 423.36 kg/day/m$^2$ The surface area of the globe is 5.1 x 10$^{14}$ m$^2$ - so 423.6 * 5.1 x 10$^{14}$ = 2.16 x 10$^{17}$ kg/day Convert from kg to Megatons, 10$^9$ kg in a Megaton - so we get 1 mol CO$_2$/m$^2$/second = 2.16 x ...


1

Simplest explanation I can think of (hopefully no logical mistakes in it): gases, just like liquids, are fluids; bound to the same physics laws. Lighter gases "rise up", above heavier ones which "sink down". Between all these, there's gravity, which attracts them all.


1

I think the third paragraph of the article hints at what might be the thinking. In the next five years, the total area covered by artificial rain or snowfall will reach 5.5 million sq km, while over 580,000 sq km (224,000 sq miles) will be covered by hail suppression technologies. The statement added that the program will help with disaster relief, ...


1

As Jean-Marie Prival commented, methane is the biogas (after removing impurites such as $H_2S$ and $CO_2$). Biogas is renewable because "From a carbon perspective, as much carbon dioxide is absorbed from the atmosphere in the growth of the primary bio-resource as is released, when the material is ultimately converted to energy."


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