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15

A nuclear winter would be a result of large amounts of smoke blocking light from the Sun. The smoke would be from the fires started by nuclear bombs on cities, not directly from the bombs. Most bomb tests have been underground, and the above ground tests were mainly done where there wasn't much to burn, for example in the Nevada desert so they didn't ...


8

To start with, I need to write a list of assumptions that are at play, and numerous disclaimers are needed. Firstly, the IPCC scientists don't say this follows a $ln$ function at all. They say it follows whatever their computer models says it follows. This is only a first order solution. Assumptions begin here: We are considering one gas We are only ...


8

No, it is not possible that nuclear fission is responsible for climate change. So although it's theoretically possible that we could do enough nuclear fission to raise the global heat content of the earth significantly, in reality, we've done very little nuclear fission industrially, and it's a tiny tiny contribution. First, remember that burning fossil ...


6

What you are talking about is called a combined cycle engine. They are commonplace in stationary power generation, i.e. utility-scale electricity generation. There has even been some talk of combined cycle engines in cars. As pointed out in the answer by dmckee, the reason this hasn't been widely applied in cars is that no one has demonstrated an ...


6

A major part of the reason for this is due to the temperature of the ground. While the length of days in the Summer are effectively a mirror of those in Spring, you must take into consideration more than that. When Spring commences in temperate climates, it is (usually) immediately preceded by winter. Due to the Winter, the ground and/or surrounding bodies ...


5

Yes, of course, the suntan/sunburn depends on the overall energy in UV radiation coming from the Sun to one's skin and this quantity is virtually unchanged in the glaciation cycles, at least if you average it over seasons. What primarily matters is the angle between the Sun rays and the plane of the skin; and the angle between the Sun rays and the plane of ...


5

To absorb infrared light, a stretching or bending vibration of the molecule must change the molecule's dipole moment. In $N_2$ and $O_2$ there is no dipole moment regardless of how you stretch the bond. On the other hand, O=C=O can change dipole moment by the C moving toward one O and away from the other O, or by bending with the C becoming a vertex of an ...


5

Well I would mostly dismiss the concern of the type: Adding ice to the planet wouldn't remove energy from the planet, it would just add matter to the planet. Sure, it increases the mass of the biosphere, but it would (in a cursory look) also decrease the temperature since the added water is lower energy than the average. We need an additional ...


4

The article you quoted frankly reads very poorly. It quotes a lot of stuff without once noting that greenhouse effects absolutely are real and critical to the earth being habitable. I don't know who this fellow is, but if he posted here directly I'd give it an instant negative vote. You, sir, I'm giving a thumbs up for taking the trouble to ask in a forum ...


4

The most important physics with respect to cloud formation happens in what is called the Atmospheric Boundary Layer (ABL). A lot of research is done in this field, since the effects of clouds is the major source of incertainty in all climate prediction models. To get some sort of cloud formation, in my opinion you would need to have some kind of ABL inside ...


4

Assuming it's a cloudless day, then yes you will get a sunburn just as you would today. Sunburn is caused by the intensity of ultraviolet light, and this didn't change (much) during the ice age. The external temperature makes no difference: it's just the uv intensity that matters. Any skier can tell you that :-) Actually, now I think about it, it's possible ...


4

In general small scale motions (like convection and formation of local eddies) in geophysical fluid dynamics are treated as turbulence, that is a regime characterized by chaotic motions and rapid, quasi random variations of pressure, temperature and velocity. Those random processes cannot be neglected in boundary layers (layers of flow close to bounding ...


4

I would add a humidity sensor, as water vapor is the strongest green house gas . This graph may suggest other gases > Breakdown of the anthropic greenhouse gas emissions by gas. Source : IPCC, 2007 Here is an article on halocarbons.


4

The Tsar bomb released an energy of $240 \mathrm{PJ}$ . The sun releases an energy of $10^{26} \mathrm{J}$ per second. That means there is a difference of $9$ orders of magnitude (supposing that the bomb released all it energy in a second), so the effect is negigible. It's like comparing the output of a coal power plant and a microwave oven.


3

Let's look a bit closer at the claims of Doug Cotton, and of Claes Johnson, whose work Doug relies upon. It's important because this is one of the strongest claims made by those who choose to reject the notion of anthropogenic climate change. Here's the core claim, from Doug Coton: The assumption is made that so-called "backradiation" from a cold ...


3

I think, this question more specific to meteorology and climatology than pure physics, but definitely can be answered in physics terms with some meteorological comments. Thereby, your question can be redefined as: How relative humidity, temperature, pressure and height relates to level of precipitation? Firstly, we should look at basic ideas to understand ...


3

The third equation is just a sum of the two first: $$ S+\lambda A=G \Rightarrow S=-\lambda A+G\\ \lambda G=2\lambda A \Rightarrow 0=2\lambda A-\lambda G $$ Add them up and get: $$ S=-\lambda A+2\lambda A+G-\lambda G=\lambda A+(1-\lambda)G $$ which is the third equation. So, still only two independent equations and two unknowns.


3

It is implausible to think of fires on the geological length and time scales you're considering. Fires are (relatively violent) chemical reactions that quickly consume their fuel and oxidizer, so such a planet would require pretty much infinite amounts of fuel and oxygen.


3

In the tropics, the main area of precipitation is the Intertropical Convergence Zone (ITCZ). Over the oceans and over many (but not all) land anreas the ITCZ follows the maximum of incoming solar radiation. In northern summer it is north of the equator, in northern winter (=southern summer) it is south of the equator. In the mid latitiudes however, most of ...


3

Climate modelling is a giant science of its own, and the proportion of CFD/statistics depends on the particular model. In general, what models do is first a simple (often uncompressable) large-scale CFD to advect the scalar fields and then apply a bunch of subrutines simulating small scale and more complex processes, like radiation transfers, heat transfers, ...


3

If humans were able to catch all sun energy reaching the earth for their use, will the climate change? It would depend on how much of that energy ends up as heat. Currently, a proportion is reflected back into space: the Earth has a non-zero albedo - it is not perfectly black, and does reflect back into space. Pretty much all the rest does end up as heat. ...


3

I think this is somewhat of an apples/oranges comparison. The benefit from a ground-based mirror is a fixed benefit per year, and lasts as long as someone is willing to leave it on their land and keep it clean. If lots of people put up mirrors for 25 years, then dismantled them, the earth would immediately warm back up. The environmental benefit from a ...


3

Many clouds are sustained by upward currents, either thermals or generated by a front, that also determine their vertical extension. However this would be an incomplete answer. Look at the clouds as regions where temperature and pressure are such that water molecules can condensate. If a water drop leaves that region without being big enough, it just ...


3

Have you ever walked through fog? What is it made of? Lots of very small water droplets. They are so small that their weight is negligible compared to the motion of air molecules, so they fall too slowly to ever notice. Next time you boil water, and you see "steam", what is it? Same thing. The only difference between fog and a cloud is that fog is a cloud ...


3

The issue with greenhouse gases isn't primarily that they are causing temperatures to change — that's part of the reason that people are trying to steer the discussion from "global warming" to "climate change." The issue is that they change the steady-state solution for the sun-earth-sky thermodynamic system. We are changing Earth's energy budget, and ...


2

To make things simple you want to compare two atmospheres that are identical, except that one has infinitessimally more of some IR absorber. In the second case, some IR photons that were traveling upwards are absorbed, and thermalized (i.e. the energy is transferred to the surrounding gas molecules, before being re-emitted). The IR photons are basically ...


2

The seasons on earth are caused by the rotation of the earth around the sun in addition with the inclination of the axis of the earth. This causes the angle of incident sunlight to be lower in winter and higher in summer. Now, the inclination of the axis of the earth is pretty constant. But if that axis would shift in some funny way, you could have any ...


2

N-body problem should pretty well cover this. Solving the almost intractable problem of three gravitating mass goes back to Newton. http://en.wikipedia.org/wiki/N-body_problem#Three-body_problem Quoting from the above article: "Specific solutions to the three-body problem result in chaotic motion with no obvious sign of a repetitious path." So assuming ...


2

The radiative portion is actually pretty straightforward. For the absorption of sunlight you multiply the strength of the sun (usually taken as 1000 watt/meter**2 at sea level by 1 minus the albedo, and multiply by the cosine of the angle. For IR, you need to know the emissivity (but for most surfaces .95 to 1 can be assumed), and use the Stefan Bolzmann ...


2

There CERES satellite has been measuring light reflected from Earth. In principle the raw data is available from NASA though I imagine some work will be necessary to process it.



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