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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 ...
gerrit's user avatar
  • 11.7k
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). ...
Ken Fabian's user avatar
  • 2,120
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 ...
BarocliniCplusplus's user avatar
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 ...
Kevin's user avatar
  • 351
23 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 ...
craq's user avatar
  • 327
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 ...
f.thorpe's user avatar
  • 13.8k
22 votes
Accepted

Why is CO₂ abundance in the atmosphere still small?

The mass of the atmosphere is 5.1 × 1018 kg, which is 5.1 × 1015 t. As stated in the edited question, industries emits 1.5 billion metric tons of carbon dioxide each year, That's 1.5 × 109 t. The ...
Fred's user avatar
  • 24.8k
20 votes

Why is CO₂ abundance in the atmosphere still small?

As well as the atmosphere having a lot of mass, there are many processes which remove CO2 from the atmosphere, see the wikipedia article for the carbon cycle. Plants sequester it as biomass, some of ...
llama's user avatar
  • 309
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 ...
AtmosphericPrisonEscape's user avatar
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, ...
Camilo Rada's user avatar
  • 17.7k
13 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 ...
Dikran Marsupial's user avatar
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 ...
Yolanda Pan's user avatar
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 ...
f.thorpe's user avatar
  • 13.8k
9 votes
Accepted

How much does overpopulation affect the carbon dioxide concentration in the air in terms of just breathing?

Human and animal respiration has no global warming impacts. The CO2 released by respiration is in balance with the CO2 absorbed by the plants that became the foods that were the source of the CO2 ...
Ken Fabian's user avatar
  • 2,120
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: ...
DavePhD's user avatar
  • 5,962
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 ...
Will's user avatar
  • 504
8 votes
Accepted

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 ...
f.thorpe's user avatar
  • 13.8k
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 ...
Camilo Rada's user avatar
  • 17.7k
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 ...
Camilo Rada's user avatar
  • 17.7k
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 ...
Turksarama's user avatar
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....
JeopardyTempest's user avatar
6 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 ...
Han Zhengzu's user avatar
  • 2,469
6 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 ...
spmoose's user avatar
  • 169
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 ...
Deditos's user avatar
  • 3,960
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 ...
Deditos's user avatar
  • 3,960
6 votes
Accepted

Why doesn't earth radiate at wavelengths where there is strong absorption?

Due to the large optical thickness, the outgoing radiation is emitted at stratospheric temperatures (the black-bodies indicated by ~210K temperatures). Keep in mind that the black-bodies in the graph ...
AtmosphericPrisonEscape's user avatar
5 votes
Accepted

How can we calculate the temperature of the atmosphere, including the greenhouse effect?

One can account for greenhouse gas effect for Earth's temperature in simple energy balance model in following manner. Assume that fraction $f$ of longwave radiation emitted by Earth's surface is ...
Harish's user avatar
  • 797
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 ...
Deditos's user avatar
  • 3,960
5 votes

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

The NASA has recently lowered their recommendation for astronauts on the ISS from 7000 ppm to 5300 ppm $\small\mathsf{CO_2}$ NASA has continued to lower $\small\mathsf{CO_2}$ exposure levels for ...
asmaier's user avatar
  • 159
5 votes
Accepted

USA and UK government report on plane emissions: 200% difference... which is right?

I've looked into this briefly and noticed a few things that are worth pointing out. First, your EPA table looks like it was based on Table 8 of this EPA pdf: https://www.epa.gov/sites/production/...
Deditos's user avatar
  • 3,960

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