Any gas that is at least partially opaque (not transparent) to infrared light.
Examples are water vapor, CO2, and methane.
Water vapor comes from evaporating water.
CO2 somes from oxygen chemically combining with carbon. That can be fire or other chemical processes.
Methane is natural gas, CH4. It is produced biologically but it is also known to exist in large amounts all over the universe even in (likely) lifeless places.
A greenhouse gas (sometimes abbreviated GHG) is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect. The primary greenhouse gases in the Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone. In the Solar System, the atmospheres of Venus, Mars, and Titan also contain gases that cause greenhouse effects. Greenhouse gases greatly affect the temperature of the Earth; without them, Earth's surface would average about 33 C° (59 F°) colder than the present average of 14 °C (57 °F).
Greenhouse gases are everywhere. Water in the atmosphere is a much more potent greenhouse gas than the fabled carbon dioxide. Despite popular misconceptions , only neglibibly significant amounts come from combustion. The vast bulk of CO2 is being released by the Oceans, as they track planetary warming that set in about 800 years ago.
Need I explain where water vapour comes from too ?
Green house gases are gases that get trapped in the atmosphere. They come from us using too many things that can create smoke, and the sun.
The world's number 2 source of organically produced methane comes from termite farts yet the hysterical AGW cultists screech about methane from cattle farms. When are these AGW cultist lunatics going to demand a war on termites to save the earth from exploding due to global warming?
Well we are not here to do your schoolwork You need to think for yourself
http://en.wikipedia.org/wiki/Greenhouse_...
BTW greenhouse is one word
gases in a greenhouse, nitrogen, oxygen, argon and a little co2, and they come from the AIR
Out of your butt - out of a cow's butt - out of the activity of untold billions of ants and other insects, the rotting of vegetable material, a few billion automobiles, people burning stuff and heating their houses, people burning umpteen tons of coal to make electricty.
gases that trap heat and they are natural
Own words please
