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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41 votes

Is there any experiment to prove that CO2 with the atmosphere concentration can have greenhouse effect?

Your question about water vapour is quite a common one among people learning about the greenhouse effect. Once you discover the relevant proportions of water vapour and CO2 in the atmosphere, it's ...
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  • 5,380
40 votes

CO₂ level is high enough that it reduces cognitive ability. Isn't that a reason to worry?

There looks like legitimate cause for further study, preferably by scientists breathing air under 950 ppm $\small\mathsf{CO_2}$ (this study showing a 15% decline in cognitive ability at this level). ...
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  • 1,178
26 votes

Why don't green house gases escape into space?

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 ...
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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
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
22 votes
Accepted

Why is Carbon Dioxide a Greenhouse Gas whereas Ammonia is not?

A molecular gas is a good infrared absorber if it has several atoms (not just 2, like O2 and N2) or if it is hetero-nuclear (e.g. CO and NO). These type of molecular arrangements allow more infrared ...
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  • 12.7k
14 votes

Why don't green house gases escape into space?

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 ...
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13 votes

How CO$_2$ warming effect stays overnight?

CO$_2$ doesn't significantly interact with solar radiation or UV, and doesn't store any significant amount of heat. What CO$_2$ effectively does is scattering infrared radiation emitted by the Earth, ...
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12 votes

Can anyone explain the reason why CO$_2$ increases global temperatures (not the simplistic greenhouse analogy provided for public consumption)?

Borrowing an explanation from one of my other answers, the basic mechanism of the greenhouse effect is roughly as follows (note this is also a simplified model) The Earth is in (to all intents and ...
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11 votes

Is there any experiment to prove that CO2 with the atmosphere concentration can have greenhouse effect?

Experiments don't necessarily prove things, per se; and in particular, a single experiment tends not to prove anything - at the very least, replication of the experiment is required. Experiments ...
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  • 4,060
9 votes

Are cattle really contributing to global warming?

Let's just talk about cattle here and ignore other factors related to cattle production for now. The current cattle number (93 million) you found is probably the total number of dairy cow and beef ...
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9 votes

Why can't we increase cloud coverage of the Earth to reduce mean temperature by flooding basins to increase evaporation?

Barring the technical feasibility of what you are proposing, there's a few points to consider which make your proposal problematic. Water vapor is a greenhouse gas. If you increase evaporation, you ...
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8 votes

CO₂ level is high enough that it reduces cognitive ability. Isn't that a reason to worry?

Two recent studies tend to contradict the 2016 study mentioned in Ken Fabian's answer. Acute Exposure to Low-to-Moderate Carbon Dioxide Levels and Submariner Decision Making (June 2018) reports: ...
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  • 5,892
8 votes

Which method is used to calculate tonnes carbon from tonnes CO$_2$ equivalents of GHGs?

OK it depends a lot on what exactly you mean. There is a known problem with people talking about "carbon" / "atmospheric carbon" / "Carbon Dioxide" and using the terms imprecisely - so there is often ...
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  • 494
7 votes

The atmosphere and the dispersion of greenhouse gases

The short answer is that greenhouse gases occur at all levels in the atmosphere. However, the concentrations can vary with altitude. In the case of greenhouse gases that are always in a gaseous state ...
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7 votes

Is there any experiment to prove that CO2 with the atmosphere concentration can have greenhouse effect?

The short answer to your question really is just this: Yes, CO2 causes global warming. There are many resources out there on the internet that explain this in about as much detail as you can tolerate,...
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7 votes
Accepted

How to calculate the temperature of Earth's surface

An easy calculation is to start with the solar constant, the power (energy per unit time) produced by solar radiation at a distance of one astronomical unit. This is 1.361 kilowatts per square meter. ...
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7 votes

Is there any experiment to prove that CO2 with the atmosphere concentration can have greenhouse effect?

To see why we can't perform an experiment in lab conditions to verify the greenhouse effect, we need to start by considering how the [rather badly named] greenhouse effect operates: The Earth is in (...
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7 votes

About the actual radiative impact of greenhouse gas emission over time

There is no doubt that the sooner the mitigation effort happens, the greater will be its impact. In other words, the impact on year 2100 climate of the sequestration of 20 billion tons $\ce{CO2}$-eq ...
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7 votes

Why is Carbon Dioxide a Greenhouse Gas whereas Ammonia is not?

The common factor among Greenhouse gases is that they absorb and scatter infra-red light. The Greenhouse effect is caused when energy coming in from the sun is prevented from escaping again. The Sun ...
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7 votes

Time for water vapor to generate more greenhouse effect than latent heat?

This is actually hinted at in the typical Trenberth energy budget diagram for the Earth: The $86.4\mathrm{\frac{W}{\,m^2}}$ is that energy movement up into the atmosphere from vaporization. The $340....
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6 votes

Is there any experiment to prove that CO2 with the atmosphere concentration can have greenhouse effect?

The Faint Young Sun Paradox - how greenhouse gases can keep a planet warm: When the Earth formed 4.5 billion years ago the Sun was around 30% less luminous than it is today and it has increased ...
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  • 2,201
6 votes

What exactly is "Land-Use Change and Forestry"?

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 ...
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  • 12.7k
6 votes
Accepted

Is it true that methane is responsible for nearly one-third of all warming?

Yes, this is broadly true. I haven't looked into much of the report yet, but I suspect that the BBC are referring to Fig 7.7 for an estimate of the observed warming attributed to changes in methane ...
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  • 3,133
6 votes

Why does the mainstream greenhouse gas theory for global warming ignore the mass of the surface?

You’re possibly thinking of the steady state descriptions, as shown in something like the Trenberth diagram below. These are steady state descriptions of energy flows rather than energy stores, in ...
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  • 3,133
5 votes

What is the ratio of infra-red light absorbed by green house gases?

There is no simple relationship since it all depends on the frequency (IR spectral lines for most species of molecules are a mess). The most direct and precise way of calculation is through line-by-...
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  • 2,083
5 votes

Methane remote sensing?

I found a great paper named Remote Sensing of Particulate Pollution from Space: Have We Reached the Promised Land? and collected some remote sensing instruments doing CH4 measurement in the chart ...
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  • 2,439
5 votes

Are plastics a carbon sink and how much carbon is released to the atmosphere making them?

The idea of a carbon sink is a bit misunderstood here. The idea of a carbon sink is a reduction of carbon that comes from the atmosphere. It must “fix” carbon that is already in the air. Trees are a ...
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  • 159
5 votes

Effective Temperature of a Planet and Surface Temperature due to Greenhouse Effect

I think you’re not far off with your understanding, but maybe I can put in a few comments to make things clearer. I often get confused because most diagrams for the Earth energy budget and net ...
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