How can greenhouse gases effect the climate of the earth?

Question

Greenhouse gases make up less than 1% of the earths atmosphere, yet people seem to think that they cause global warming. Could someone please explain to me how such a small amount of gas can effect the whole atmosphere?

What I really want is a scientific explanation about proportions...how can something so small have such a huge effect. Just saying that greenhouse gases effect the atmosphere isnt good enough. Where are the facts?

Answer 1

There are a couple of ways to approach this from a scientific basis. The most powerful way of looking at it is to look at the total energy flows.

Suppose that greenhouse gasses do cause only an effect proportional to their concentration in the atmosphere. CO2 makes up 0.038% of the atmosphere. Suppose it only affects 0.038% of the energy received from the sun.

Energy received from the sun every year is about 5.5 × 10^24J. 0.038% of that is 2.1 x 10^21J, which is a lot of energy. It is about 5 times the total amount of energy used by mankind every year!

So what can that much energy do? Lets see how much we could heat the oceans. The total mass of the oceans is about 1.4 × 10^21 kg. Since the entire ocean will not be heated for centuries because the deep ocean currents are very slow let us consider just the first 100 meters. The average ocean depth is 3,711 meters. The heat capacity of water is 4186 J/(kg·C).

The amount of heating per year then would be:

2.1 x 10^21 J/yr / ( 1.4 x 10^21 kg x (100 m / 3711 m) x 4186 J/(kg-C)) = 0.013 deg C / yr

So that means that just 0.038% of the sun's annual energy striking the earth can heat the oceans by 0.013 deg C per year. That is just about how fast the ocean is actually heating up. Records indicate the ocean is heating at a rate of about 0.13 deg C/ decade. That my numbers match the actual rate is just a coincidence based on the depth of the heating effect I guessed at of 100 meters. It is actually much more complicated but this calculation does give you an idea of why this can actually be happening.

The point should be very clear, that even very tiny changes in the atmosphere could have big changes on earth because there is such a tremendously large amount of energy hitting the earth from the sun.

Answer 2

Each carbon dioxide molecule absorbs some infra red light. I don't know how to calculate how much is absorbed by each molecule, but even one molecule would absorb some. So it is just a matter of how many carbon dioxide molecules does it take to absorb enough infra red light to cause what amount of warming. It is not an on/off thing, it is a gradual change from none to all. Clearly the very small amount now in the air is closer to none than it is to all. That is the only reason that our "puny" activities can have an effect at all, because it is so small. The source below was the best I could find, but there must be better ones. The answers that deal with your question are quite far down the page but are easy to find by scanning the bold type headings.

Answer 3

hey email me once you get the answer, i need to know. but from what i researched, greenhouse effect is an effect where heat is trapped in the earth, causing the temperature to rise. but you must be kidding me. greenhouse gases don't take up less than 1% of the earht's atmosphere. greenhouse gases take up around 30%. it's our consumption of oil that increases CO2 emissions. CO2 is a greenhouse gas. water vapor is a natural greenhouse gas so we can't do anything about that. most greenhouse gases consist of water vapor. since gasoline is a hydrocarbon, at a certain melting point, the bonds will break and soon release CO2. more CO2 = increase in global warming.

Answer 4

Water vapor. The alarmists' pet CO2 makes up 0.036% of greenhouse gasses, and about 0.00003% is man-made. If you were to say to an alarmist that whatever plans they may come up with will increase unemployment by 30%, then they'll say that it's a small, insignificant amount; but apparently 0.00003% is a massive, apocalyptic percentage.

Answer 5

I guess as the makeup of the gas slightly changes this has a significant effect on keeping the heat inside the atmosphere.

Answer 6

greenhouse gases are water vapour, carbon dioxide, methane etc .these gases absorb the sunlight reflected from the earth's surface and radiate it back towards the earth's surface and also acts as a blanket over the earth's surface,thereby maintaining ideal climatic conditions(not too hot nor too cold)for lifeforms.due to increased emission (even when they are in traces)considerably alter amount of sun's heat reaching earth's surface leading to global warming ,increase in sea level due to melting of polar icecaps thus leading to submergence of low lying coastal areas,increased evaporation ,destruction of climatic balance ultimately leading to destruction of habitats and to extinction of life forms

Answer 7

Even a small amount can block the suns rays from getting back out in order to cool the earth...
That heat goes back to our water and land...

Not to mention who likes breathin' in that nasty stuff EEWWwww!

Answer 8

It can make it hotter. It makes colder nights and hotter days.

Answer 9

look up "Medieval warm period"