greenhouse gasses?

Question

I know that Global Warming is caused partially by Greenhouse Gasses, but what exactly is a greenhouse gas? And does this mean actual Greenhouses are bad for the enviornment? I bet that sounds really stupid right there :-/

Answer 1

The term Greenhouse Gases isn't the most accurate one as it's not really comparable to a greenhouse. The way a greenhouse traps heat is different to the way the atmosphere traps heat.

To answer your second point first - I've never come across anything to suggest greenhouses are bad for the environment; if anything they encourage plant growth which is good for the environment because plants take carbon dioxide out of the atmosphere.

Returning to your first point - what is a greenhouse gas (GHG). The term is used to describe those gases that have the ability to trap heat within our atmosphere and they do this because there's a difference between heat from the sun entering our atmosphere and heat from the Earth leaving it.

Heat from the sun, solar radiation, can easily pass through the atmosphere and the Earth absorbs this heat. The heat radiated back by the Earth is thermal radiation and this is a different wavelength to solar radiation. It's still heat but a different kind of heat and it has problems escaping from the atmosphere. It's this trapping of the heat which is referred to as the greenhouse effect.

Almost all the atmosphere is made up of just three gases - nitrogen, oxygen and argon and together they account for more than 99.9% of the atmosphere but they're not greenhouse gases.

Only about 0.05% (one part in every 2000) of the atmosphere is a greenhouse gas and the main one is carbon dioxide, the other two important ones are nitrous oxide and methane. These three gases occur naturally but they're also produced by human activities.

There's a whole host of synthetic greenhouse gases, many of which have now been banned. You've probably heard of the group known as CFC's (chlorofluorocarbons), there are similar groups as well such as HFC's and HCFC's (hydrofluorocarbons and hydrochlorofluorocarbons). These gases are extremely effective as greenhouse gases go and they also destroy the ozone layer (the reason they're banned).

One greenhouse gas I haven't mentioned is water vapour, this is almost entirely naturally occurring and the amount in the atmosphere varies considerably. Unlike other greenhouse gases there's a limit as to how much water vapour the atmosphere can contain, when the limit is reached the excess falls as rain. With the other GHGs they just keep on accumulating in the atmosphere. Although most of them deteriorate over time we're adding to them much faster than they're being naturally removed.

You asked if GHGs are bad for the environment and the answer is both yes and no. If there weren't any GHGs there would be no greenhouse effect and the planet would be so cold that life would never have evolved, this natural greenhouse effect is essential to life on earth.

The problem in the last 150 years or so has been that human activities have produced far more greenhouse gases then nature can handle and as a result the planet is now warming many times faster than it should be doing naturally. Basically it's a balancing act and we've messed it up.

Answer 2

No, greenhouses are not bad for the environment. In fact, they produce plants to improve the environment, plants we would perhaps not normally have access to.

But the term Greenhouse Gas comes from how the greenhouse generates the heat to keep tender plants growing in harsh climates.

As in regular houses, the sun's heat comes through the glass on short wavelengths, and strikes something that absorbs the energy. The heat generated in the absorption is then re-radiated in part, but at a longer wavelength, which will not penetrate glass, so it is locked into the greenhouse.

Greenhouse gases have the same effect on the earth...let the short-wavelength radiation thru, and when that heats the earth and is changed into longer-wavelength heat, the heat is blocked by the GHG from escaping.

In greenhouses there are windows to let out the hot air if it gets too hot, but as of yet we have not orbited a GHG opener to let the heat escape.

Though we might make a heat engine to drive a laser and send it back out into space in a beam...and hope nothing got in the way of the beam of concentrated heat!

Answer 3

Greenhouse Gas - Any gas that absorbs infra-red radiation in the atmosphere.

From the first link:
"The greenhouse effect is important. Without the greenhouse effect, the Earth would not be warm enough for humans to live."

Answer 4

Some gases ("greenhouse gases") let sunlight in, which warms the Earth, and then block that heat from leaving. That's the "greenhouse effect", and it's a natural thing, mostly caused by water vapor.

Man is making excessive amounts of greenhouse gases, mostly by burning fossil fuels. That causes the delicate natural balance to go out of whack and the Earth warms. That's global warming.

It won't be a Hollywood style disaster. Gradually coastal areas will flood and agriculture will be damaged. But it will be very bad. Rich countries will cope, but it will take huge amounts of money. In poor countries many people will die of starvation, but not all of them.

Most scientists say, in 20-50 years. But we need to start right now to fix it, fixing it will take even longer than that.

More information here:

http://profend.com/global-warming/

Lots of numerical scientific data proving it real here:

http://en.wikipedia.org/wiki/Image:Climate_Change_Attribution.png

http://www.ipcc.ch/SPM2feb07.pdf

Answer 5

Carbon dioxide receives the most press because it is the one that we have changed by the largest amount. The most common greenhouse gas is water vapour, and it's responsible for the majority of the 33C warming caused by the greenhouse effect. However, it's not believed to force changes in the climate because it's believed temperatures must change first for there to be long term changes in the amount of water vapour. If it's too cold, water vapour falls out. If it's too hot, it evaporates in. It doesn't go there by itself! By contrast, changes in carbon dioxide levels have persisted for decades and may continue for centuries. Many other gases; ozone, nitrogrogen triflouride, nitrogen oxides, methane etc are also greenhouse gases but are generally less abundant. A climate model says that if water vapour were removed, 36% of the greenhouse effect would disappear. If Carbon dioxide were removed, 9% of the greenhouse effect would disappear[1]. Using rough figures, that's a 12C cooling if water wasn't there and a 3C cooling if CO2 wasn't there. jpturboprop: the eruption of Mount Pinatubo in 1991 has been associated with worldwide, measurable changes in climate (albeit, short lived ones). The energy of its seismic activity was ~6.3x10^13J [2]. Annual human energy consumption is 487x10^18J[3]. Human energy consumption, every year, is 7.7 MILLION times larger than the energy from the Mount Pinatubo eruption. If something 7.7million times smaller than human activity can alter climate, then it would make sense that humans could affect things too. As an aside, we'd need to detonate millions of nuclear weapons every year for their energy output to match our current primary energy consumption. EDIT: Historically, CO2 rises appear to have trailed temperature[4], today is a different situation and so can't really be compared. James E says that as CO2 leaves solution (in the oceans), the pH goes down. Afaik, this is incorrect. CO2 dissolved in water leads to (negative) carbonate & bicarbonate ions and associated hydrogen-I ions. pH is a measure of the concentration of H+ ions (pH=-log[H+], low pH is acidic). As CO2 leaves the oceans, the pH rises: it does NOT go down!

Answer 6

Green house gasses in simple terms are gasses like co2 that comecs from cas and stuff floats up in the atmospherer and acts like a green house (thats why it has the name) and lets sun light in and warmpth in and holds it in more than the atmosphere would normaly. Much like a greenhouse. It has nothing to do with greenhouses being bad. :)

Answer 7

Green house gases are the gases which is used to keep the earth warm. It includes carbon dioxide and other gases. This is called global warming. Nowadays, this gases are getting increasing. So our earth's heat is getting increasing.
This is due to pollution. For example:Factory smoke,Petrol wastes,etc...
So we must preserve our nature.

Answer 8

1. Research Carbon Dioxide [CO2].
2. No.

Answer 9

Not stupid at all, have a look here

http://www.ozenergy.net