78 votes

How do 'greenhouse gases' let heat in, but not let it out?

In a nutshell: The radiation that enters is shortwave radiation from the sun. Solar radiation is dominated by visible (as well as UV and near infrared) radiation with a wavelength mostly between 0.2 ...
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45 votes

Why doesn't the 71% water of the earth dry or evaporate?

There are two ways this problem needs to be looked at. The first is more astronomy than Earth science. The Earth as an entire system is largely contained. Its gravity and magnetic field retains ...
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  • 5,707
39 votes
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Why were both the sun and the moon red today?

Smoke. There was significant smoke across the USA, which attenuated the light from the sun/moon due to increased scattering. The smoke particles effectively cause the light to reflect in different ...
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  • 12.7k
35 votes

Why is the temperature *still* rising?

"So much work"? Actually, compared to the global rate of greenhouse gas emissions, it's a case of "so little work"! From a scientific perspective the 'economists' solution' of carbon trading was ...
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31 votes
Accepted

What would be the temperature of earth if there was no atmosphere?

According to Wikipedia an approximate average surface temperature for a bare earth is 274.5 K. This scenario is quite reasonable in my opinion as stripping the atmosphere without changing much else ...
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  • 2,602
30 votes
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Why are mornings cooler than nights?

The Earth is always radiating heat to the space. But in the day the Sun delivers some heat. The net heat flux is then defined as the sum of those two factors. If the energy delivered by the Sun is ...
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  • 618
28 votes

Is the color of the sky the same everywhere on earth?

Absolutely not. While the answers by casey and farrenthorpe correctly state that the blue color is due to Rayleigh scattering, the composition of the atmosphere varies considerably from place to place ...
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  • 1,374
28 votes
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Where is the calmest place on Earth?

The main resistance that winds have to their movements comes from the topography and surface obstacles. Therefore, as a general rule the closer to the surface the less wind you will find. But I guess ...
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25 votes
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Is it true that a butterfly flapping its wings can result in a tornado in a distant location?

The butterfly is a colourful illustration of Chaos Theory, and the word butterfly came from the diagram of the state space (see below). A system that is chaotic is extremely sensitive on its initial ...
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  • 11.1k
25 votes

Why doesn't the 71% water of the earth dry or evaporate?

Why doesn't 71% water of the earth dry or evaporate? The simple answer: Because it rains. The not so simple answer: By some estimates, the Earth has already lost about a quarter of its water, and it ...
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  • 20.2k
25 votes

How do 'greenhouse gases' let heat in, but not let it out?

Gerrit's got the technical answer; I'm going to answer for a layperson. There are two ways objects lose heat. The first, and the way people are most familiar with, is conduction. Something touches ...
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  • 351
24 votes
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Does Earth's air leak into space over time?

Earth's atmosphere does escape over time, albeit very slowly. The distribution of kinetic energies of molecules in a gas obeys (more or less) a Maxwell-Boltzmann distribution. Notice that the graph ...
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  • 356
24 votes
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What is the fastest the Earth has ever spun?

The speed of rotation of Earth is controlled by its angular momentum. And the conservation of angular momentum is a very serious law of physics (perhaps even stricter than conservation of mass). So in ...
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23 votes

Why does El Niño only exist in the Pacific Ocean and not the Atlantic/Indian Oceans?

First, to describe El Niño as a Pacific Ocean event seems overly simplistic. The effects of El Niño are felt worldwide as can be seemed by a principal component (EOF) analysis (e.g., Alexander et al., ...
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  • 14.7k
23 votes

Why is the temperature *still* rising?

Your premises are flawed due to the lack of two critical details: Population rise; the sheer number of people on the planet that are consuming resources has risen to 7 billion people. Standard of ...
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  • 12.7k
22 votes

How do 'greenhouse gases' let heat in, but not let it out?

To add to Gerrit's excellent answer, I'd like to add a couple more Images. Images always help clarify things for me. Firstly, this one shows the spectrum light coming from the sun in red. The peak is ...
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  • 317
21 votes
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How will cloud feedback effects on the climate change as the result of global warming?

We don't really know. Climate models agree that the feedback is profound. Significant. Unfortunately, they do not agree about the magnitude of the feedback. Nor about the sign. The problem is ...
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  • 11.1k
21 votes

What is the steepest surface that can hold snow?

What's the minimum "uprightness" for it to not get obscured by snow and stay readable throughout the year? The answer to this problem is not in the angle at all. No amount of math will give ...
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  • 360
21 votes
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To what extent is hydroelectric power really renewable?

Electricity from waves, from hydro (both run-of-river and storage) and from wind, are all indirect forms of solar power. Electricity from tides is different, and we can deal with that in a separate ...
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  • 4,080
21 votes
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What is the origin of the dominant atmospheric nitrogen content in Earth's atmosphere?

According to the recent paper in Nature Geoscience: Nitrogen speciation in upper mantle fluids and the origin of Earth's nitrogen-rich atmosphere, $N_2$ originates from regions of the Earth where ...
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  • 5,892
20 votes
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What are the major differences between weather models and climate models?

The major differences between weather and climate models are many. At their core lie the same set of primitive equations, but from here there are many differences. A weather model only (skillfully) ...
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  • 13.9k
19 votes
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What is the cause of the jet streams?

The subtropical jetstream The subtropical jetstream can be explained with angular momentum arguments. In an idealized circulation model of the atmosphere, there is a hadley cell that circulates ...
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  • 13.9k
19 votes
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Coriolis effect and Cyclones

Don't think of the Coriolis force as deflecting motion clockwise/counter clockwise, but to the right (NH) or left (SH), when looking in the direction of the motion. So this is sort of 'by definition'....
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19 votes

Why are there no CO2 snowfalls on Earth?

There is more to phase change than just what you see on that graph. At temperatures and pressures that support multiple states (e.g. solid and gas) you have to look at the saturation vapor pressure ...
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  • 13.9k
19 votes

Is the Unified Theory of Climate (Nikolov & Zeller) compatible with the AGW/GHG theory in any respect?

The paper you linked lists as its first reference Volokin and ReLlez, 2014; a paper that addresses the magnitude of the Earth's greenhouse effect. The validity of the paper you found largely hinges on ...
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  • 3,294
18 votes
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Where does wind come from?

Wind is caused by pressure differences. Think of a balloon full of air; poke a hole in it and the air comes out. Why? Because the pressure in the balloon is higher than outside, and so to regain ...
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  • 13.9k
18 votes
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What woud happen to me if I touched the aurora?

The lowest reaches of an aurora is ~100 km in the air. Your problem won't be the ionized gas, it'll be that the air pressure is close to zero. Also, aurora are very diffuse, with at most a few ...
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