What if CO2 was not a greenhouse gas?

It would be hard to say precisely, but the Earth would be a very different place. The mean temperature would certainly be below freezing and there would be no liquid water on the surface of the planet. The paper by Gavin Schmidt estimates how much the addition or removal of each GHG component has

http://pubs.giss.nasa.gov/docs/2010/2010_Schmidt_e...

In it he finds that the removal of CO2 from the atmosphere gives a net forcing of -28 W/m^2. For comparison a doubling of CO2 gives a net forcing of +4 W/m^2.

EDIT for jim z: Actually the paper does look at cloud forcings also, although how he specifically treated cirrus clouds I don't know. However on a planet without any liquid water I would expect substantially less cloud cover anyway. Much of the cirrus cover is generated by thunderstorms (which won't exist) and mid-latitude baroclinic storms (which may not exist either).

Life would not be possible if CO2 were not a greenhouse gas. Living things depend on the energy released in making CO2 to make ATP. As a consequence of its biological role, CO2 has a dipole moment and molecular compounds wiht dipole moments absorb infrared.

Your hypothetical question about what the temperature of Earth without CO2 forcing could be answered by considering what Earth would be like without CO2. Would the water vapor still be in the atmosphere? The answer is no.

In order to double the amount of water vapor in the atmosphere, a temperature increase of about 10 degrees C is required, but such a doubling of water vapor will not produce a 10 degree C of temperature increase. If it did, we would have a runaway greenhouse effect. Earth without CO2 and with water vapor in the atmosphere would be warmer than if there were neither CO2 or water vapor in the atmosphere but it would be much colder than it is now.

i've got faith that Mars is a much better occasion of a greenhouse gasoline moderating a planets temperature. Mars' atmosphere is ninety 5% CO2 with a diurnal temperature selection from -89 to -31 C. It does this with a photo voltaic irradiance of basically 589.2 W/m2. it somewhat is atmosphere is dry and has no significant cloud impression. without the greenhouse result from CO2, the night time temperature may well be close to to the darkish area of Mercury -184.4 C.. the ambience would desire to loose adequate warmth at night that CO2 ought be precipitating out of the ambience each and each Martian night, even though it would not get that chilly.

I have a theory about the increase in greenhouse gases. As you know, catalytic converters were first mandated back in 1975 . Also powerplants that use oil, natural gas and coal have catalytic converters, I believe, It is possible that we added much more water vapor into the atmosphere than normally before 1975. Carbon dioxide is more of a permanent greenhouse than water vapor from any source. Lets suppose we remove all catalytic convertters , I can only imagine what it would be alike. I dont know, really. Maybe powerplants should stop releasing water vapor through catalytic converters and instead condense it into drinking water This should not be an expensive new regulation on top of layers of regulations burdening powerplants. We will probably be drinking water out of tailpipes later on.. You never know when you will be maroooned in a hot desert one hot summer day, you know? We will probably add a extra long coiled exhaust pipe to help condense water vapor before letting the exhaust fumes go. We will all have water coolers while on the go!

I don't think the question is answerable though I suspect that won't stop alarmists from trying. You have to realize that climate is due to many factors and those factors change with temperature among other things. If CO2 were not present or didn't act as a GHG, the effect of water is probably not as a simple as subtracting the supposed CO2 warming effect.

Obviously since we live in a period of ice ages, our climate is very near to moving into a glacial episode. It probably wouldn't take much to freeze us.

Note: Sometimes the best answer is we don't know. Alarmists, being they are normally arrogant and full of themselves don't like this answer. That is why they are the stupidest among us. When you can't even acknowledge what you don't know, you can't learn anything. They don't live on planet Earth. I am guessing that Peg's link didn't take into account the change the sirus clouds as one tiny example.

What a mindless nonsensical question of babble. What if this ,what if that lol. But not far off the mark in a way because co2 is a very very minor greenhouse gas and definitely not the 2nd most powerful by a long shot. Basically co2's effects are so small it barely qualifies as a greenhouse gas.

No greenhouse effect? The mean global temp would be about ~-15C more or less.

Current mean global temp is 15C. Greenhouse effect raises temp a little more than 30C (not out of line with the 33C to 34C you provide). This means that the average global temp would be about -15C if no greenhouse effect existed (no greenhouse gases). It could be a couple of degrees cooler if we use 33C-34C instead of 30C.

http://earthobservatory.nasa.gov/Features/EnergyBa...

I'm not sure on the effect of CH4 and N2O. They would have some warming effect because they have much greater of a forcing effect than CO2.Water vapor and CO2 are the 2 biggest influences just because they are more abundant than CH4, N2O, and the others that occur in even lower concentrations. I think that -15C might be a little too cool, but still much closer to what the temp would be compared to the current temp of 15-16C.

If CO2 were not a greenhouse gas then airheaded anti-science deniers of science COULD actually be on another planet (Venus) instead of just acting like they are.

That is an essay question on a take home test if I ever heard one. Seriously, go do some research on your own.

According to Wiki you would have somewhere between 9% to 26% less Greenhouse Effect, but I think that is grossly exaggerated, but that's what Wiki says anyway.

Gases, percentage contribution to the greenhouse effect

http://en.wikipedia.org/wiki/Greenhouse_effect#Gre...

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