Comments on: Is It Possible for a Small Amount of CO2 to Warm the Earth? http://www.opentemp.org/main/2007/12/03/is-it-possible-for-a-small-amount-of-co2-to-warm-the-earth/ An Open Analysis of the Historical Temperature Record Fri, 30 Jul 2010 01:29:50 +0000 http://wordpress.org/?v=2.2.3 By: sue http://www.opentemp.org/main/2007/12/03/is-it-possible-for-a-small-amount-of-co2-to-warm-the-earth/#comment-269 sue Fri, 14 Dec 2007 18:28:26 +0000 http://www.opentemp.org/main/2007/12/03/is-it-possible-for-a-small-amount-of-co2-to-warm-the-earth/#comment-269 I'm not a scientist (duh), but I have direct observational experience from working in commercial greenhouses, that show the impact of vegetation/moisture on temperature when all other conditions are identical. Yoder Bros. a large commercial grower, had a California plant that produced chrysanthemum cuttings. The plant consisted of more than a dozen identical clear glass and wood frame greenhouses. Each greenhouse had eight long parrallel, beds about 18" off the ground, and four giant fans at the back of the green house, at blew air accross large fiber mats that water trickled over. Many times during my tenure at this operation I had occasion to work in the same day, (even within the same hour) in greenhouses that were completely full of plants and those that were completely empty of growing plants (removing dried remains and preparing beds for new planting). The only differences between the comparison greenhouses were the presence or absence of plants and the presence or absence of the water vapor resulting from the twice a day watering of the growing plants. It was entirely typical for the growing house to have a temperature of 86 degrees F while the bare house (right next door at the same time of day) had a temperature of 120 degrees F. Thermometers were located every few feet in all greenhouses and easy to read. Thirty to forty degree differences between houses were commonly observed through out the summer. I’m not a scientist (duh), but I have direct observational experience from working in commercial greenhouses, that show the impact of vegetation/moisture on temperature when all other conditions are identical. Yoder Bros. a large commercial grower, had a California plant that produced chrysanthemum cuttings. The plant consisted of more than a dozen identical clear glass and wood frame greenhouses. Each greenhouse had eight long parrallel, beds about 18″ off the ground, and four giant fans at the back of the green house, at blew air accross large fiber mats that water trickled over.
Many times during my tenure at this operation I had occasion to work in the same day, (even within the same hour) in greenhouses that were completely full of plants and those that were completely empty of growing plants (removing dried remains and preparing beds for new planting). The only differences between the comparison greenhouses were the presence or absence of plants and the presence or absence of the water vapor resulting from the twice a day watering of the growing plants. It was entirely typical for the growing house to have a temperature of 86 degrees F while the bare house (right next door at the same time of day) had a temperature of 120 degrees F. Thermometers were located every few feet in all greenhouses and easy to read. Thirty to forty degree differences between houses were commonly observed through out the summer.

]]> By: John V http://www.opentemp.org/main/2007/12/03/is-it-possible-for-a-small-amount-of-co2-to-warm-the-earth/#comment-258 John V Thu, 13 Dec 2007 04:40:13 +0000 http://www.opentemp.org/main/2007/12/03/is-it-possible-for-a-small-amount-of-co2-to-warm-the-earth/#comment-258 Alan: I don't believe your conclusion is correct. The moist air lapse rate only applies when the air is 100% saturated, such that additional expansion (cooling) causes condensation (warming). If the relative humidity is 98%, the dry adiabatic lapse rate still applies. I had thought that RH would go up with altitude, but Paolo M over at CA has taught me otherwise. For the record, I made a similar mistake about moist vs dry air but came to a different conclusion. You are also neglecting the greenhouse gas properties of water vapour, which is the primary reason it's considered a positive feedback. Other water vapour properties such as reflective clouds and surface evaporation are negative feedbacks. Alan:
I don’t believe your conclusion is correct. The moist air lapse rate only applies when the air is 100% saturated, such that additional expansion (cooling) causes condensation (warming). If the relative humidity is 98%, the dry adiabatic lapse rate still applies.

I had thought that RH would go up with altitude, but Paolo M over at CA has taught me otherwise.

For the record, I made a similar mistake about moist vs dry air but came to a different conclusion.

You are also neglecting the greenhouse gas properties of water vapour, which is the primary reason it’s considered a positive feedback. Other water vapour properties such as reflective clouds and surface evaporation are negative feedbacks.

]]> By: Alan D. McIntire http://www.opentemp.org/main/2007/12/03/is-it-possible-for-a-small-amount-of-co2-to-warm-the-earth/#comment-257 Alan D. McIntire Thu, 13 Dec 2007 01:28:23 +0000 http://www.opentemp.org/main/2007/12/03/is-it-possible-for-a-small-amount-of-co2-to-warm-the-earth/#comment-257 Water vapor does indeed have a negative feedback. The dry adiabetic lapse rate for the atmosphere would be about 9.8 C per 1000 meters. For moist air, that drops to roughly 5 C, depending on the original temperature of the air. The moral of the story is that dry air cools more rapidly with height than moist are. The converse is that moist air is warmer at higher altitudes, and this radiation of moist air from higher altitudes is a negative feedback- Water vapor does indeed have a negative feedback. The dry adiabetic lapse rate for the atmosphere would be about 9.8 C per 1000 meters. For moist air, that drops to roughly 5 C, depending on the original temperature of the air. The moral of the story is that dry air cools more rapidly with height than moist are. The converse is that moist air is warmer at higher altitudes, and this radiation of moist air from higher altitudes is a negative feedback-

]]> By: John V http://www.opentemp.org/main/2007/12/03/is-it-possible-for-a-small-amount-of-co2-to-warm-the-earth/#comment-250 John V Mon, 10 Dec 2007 04:04:00 +0000 http://www.opentemp.org/main/2007/12/03/is-it-possible-for-a-small-amount-of-co2-to-warm-the-earth/#comment-250 jae: Obviously I meant the temperature is higher because of lower albedo and evaporation, but thanks for the correction. You seem to have found that water vapour has a negative feedback on *surface* temperature. I merely asked if the same pattern existed at the level of clouds. Based on your response, I assume you don't have an answer. It's ok to say that. jae:
Obviously I meant the temperature is higher because of lower albedo and evaporation, but thanks for the correction.

You seem to have found that water vapour has a negative feedback on *surface* temperature. I merely asked if the same pattern existed at the level of clouds. Based on your response, I assume you don’t have an answer. It’s ok to say that.

]]> By: jae http://www.opentemp.org/main/2007/12/03/is-it-possible-for-a-small-amount-of-co2-to-warm-the-earth/#comment-249 jae Mon, 10 Dec 2007 02:56:46 +0000 http://www.opentemp.org/main/2007/12/03/is-it-possible-for-a-small-amount-of-co2-to-warm-the-earth/#comment-249 12: "higher in deserts because of albedo and evaporation." Now this is really an odd response. Both of these things tend to LOWER temperatures. And, sorry, if I put the m^3 in there, it was a mistake. The latent heat of evaporation is about 0.69 watt-hr/gram of water, and that is a NEGATIVE feedback. That energy is spent at the surface. Of course you get the energy back, but too high in the atmosphere to affect your thermometer. And please tell me why the radiation models dwell on CO2 and completely ignore the most important GHG--water vapor. It falls out of the sky, unlike CO2, but at any given time, it's there! I have no qualms with the radiation demonstrations that show the average temperature of the Earth. But when you start creating this bogus "layer in the sky" that decides how much IR goes to Earth, and how much goes to space, I get very skeptical. Someone, please tell me why it's hotter in Phoenix than in Guam, if the so-called GHGs have ANYTHING to do with temperature! It's all about heat storage, not radiation. I hope I can find a way to prove this. 12: “higher in deserts because of albedo and evaporation.”

Now this is really an odd response. Both of these things tend to LOWER temperatures. And, sorry, if I put the m^3 in there, it was a mistake. The latent heat of evaporation is about 0.69 watt-hr/gram of water, and that is a NEGATIVE feedback. That energy is spent at the surface. Of course you get the energy back, but too high in the atmosphere to affect your thermometer. And please tell me why the radiation models dwell on CO2 and completely ignore the most important GHG–water vapor. It falls out of the sky, unlike CO2, but at any given time, it’s there! I have no qualms with the radiation demonstrations that show the average temperature of the Earth. But when you start creating this bogus “layer in the sky” that decides how much IR goes to Earth, and how much goes to space, I get very skeptical.

Someone, please tell me why it’s hotter in Phoenix than in Guam, if the so-called GHGs have ANYTHING to do with temperature! It’s all about heat storage, not radiation. I hope I can find a way to prove this.

]]> By: John V http://www.opentemp.org/main/2007/12/03/is-it-possible-for-a-small-amount-of-co2-to-warm-the-earth/#comment-248 John V Sun, 09 Dec 2007 23:11:44 +0000 http://www.opentemp.org/main/2007/12/03/is-it-possible-for-a-small-amount-of-co2-to-warm-the-earth/#comment-248 ClaytonB, they have indeed performed wind tunnel tests and/or flight tests. But that's not the point. The point is that Steve McIntyre's request for the derivation of the climate sensitivity from first principles is basically impossible. There are two ways to determine the value: 1. Empirically using CO2, temperature, and solar reconstructions; 2. Numerically using computer models; Another problem with determining climate sensitivity is that it has different values depending on the timescale. There are slow feedbacks (eg. glaciers melting) and fast feedbacks (eg. water vapour). ClaytonB, they have indeed performed wind tunnel tests and/or flight tests. But that’s not the point. The point is that Steve McIntyre’s request for the derivation of the climate sensitivity from first principles is basically impossible. There are two ways to determine the value:

1. Empirically using CO2, temperature, and solar reconstructions;
2. Numerically using computer models;

Another problem with determining climate sensitivity is that it has different values depending on the timescale. There are slow feedbacks (eg. glaciers melting) and fast feedbacks (eg. water vapour).

]]> By: ClaytonB http://www.opentemp.org/main/2007/12/03/is-it-possible-for-a-small-amount-of-co2-to-warm-the-earth/#comment-246 ClaytonB Sun, 09 Dec 2007 18:01:28 +0000 http://www.opentemp.org/main/2007/12/03/is-it-possible-for-a-small-amount-of-co2-to-warm-the-earth/#comment-246 "As some have said at CA, it’s like asking for the total lift of a Boeing 747 from first principles (no modelling allowed)." Yes, but I'm quite certain that they performed wind tunnel tests... “As some have said at CA, it’s like asking for the total lift of a Boeing 747 from first principles (no modelling allowed).”

Yes, but I’m quite certain that they performed wind tunnel tests…

]]> By: John V http://www.opentemp.org/main/2007/12/03/is-it-possible-for-a-small-amount-of-co2-to-warm-the-earth/#comment-245 John V Sat, 08 Dec 2007 16:41:57 +0000 http://www.opentemp.org/main/2007/12/03/is-it-possible-for-a-small-amount-of-co2-to-warm-the-earth/#comment-245 jae, I did mention the latent heat of evaporation in #6. Using common SI units, the value is 2258 kJ/kg. I'm not sure what your units are -- is the g for grams and m for metres? If so, your units don't work out. Converting your value to more standard units I get: 0.69 watt*hr/g/m^3 =0.69 watt*(3600s)/g/m^3 = 0.63 J/g/m^3 = 0.63 kJ/kg/m^3 --> what's the m^3 doing there? Anyways, putting the units aside and focussing on your point, here's my opinion: The *surface* temperature is higher in deserts because of albedo and evaporation. But don't forget that the latent heat of evaporation is recovered when the water vapour condenses into clouds. Do you have data for atmospheric temperatures at a couple of thousand feet in these areas? jae, I did mention the latent heat of evaporation in #6. Using common SI units, the value is 2258 kJ/kg. I’m not sure what your units are — is the g for grams and m for metres? If so, your units don’t work out. Converting your value to more standard units I get:

0.69 watt*hr/g/m^3
=0.69 watt*(3600s)/g/m^3
= 0.63 J/g/m^3
= 0.63 kJ/kg/m^3 –> what’s the m^3 doing there?

Anyways, putting the units aside and focussing on your point, here’s my opinion:

The *surface* temperature is higher in deserts because of albedo and evaporation. But don’t forget that the latent heat of evaporation is recovered when the water vapour condenses into clouds. Do you have data for atmospheric temperatures at a couple of thousand feet in these areas?

]]> By: jae http://www.opentemp.org/main/2007/12/03/is-it-possible-for-a-small-amount-of-co2-to-warm-the-earth/#comment-244 jae Sat, 08 Dec 2007 15:07:22 +0000 http://www.opentemp.org/main/2007/12/03/is-it-possible-for-a-small-amount-of-co2-to-warm-the-earth/#comment-244 John V: I think you forgot something in #8. Increased temperature does cause increased evaporation, but at an "expense" of 0.69 watt-hr/g/m^3. This is the latent heat of evaporation, and it is a negative feedback, since you don't get most of that energy back anywhere near the surface (except dew). See http://www.esnips.com/web/climate Also, all that solar energy is spent in heating the air column and the surface. All those molecules are "trading" radiation, and at some elevation (maybe 5km?) there is more going to space than back and forth. But there's no "cascading" of radiation toward the ground, as is commonly thought. That would be adding energy. If the radiation hypothesis is true, tell me why it is hotter in July (average and maximum temperatures) in Dagget, CA than anywhere in the tropics? After all there is no shortage of "greenhouse gases" (water vapor) in the tropics. I have been asking this question for two years now, and nobody even attempts to answer it... John V: I think you forgot something in #8. Increased temperature does cause increased evaporation, but at an “expense” of 0.69 watt-hr/g/m^3. This is the latent heat of evaporation, and it is a negative feedback, since you don’t get most of that energy back anywhere near the surface (except dew). See http://www.esnips.com/web/climate

Also, all that solar energy is spent in heating the air column and the surface. All those molecules are “trading” radiation, and at some elevation (maybe 5km?) there is more going to space than back and forth. But there’s no “cascading” of radiation toward the ground, as is commonly thought. That would be adding energy. If the radiation hypothesis is true, tell me why it is hotter in July (average and maximum temperatures) in Dagget, CA than anywhere in the tropics? After all there is no shortage of “greenhouse gases” (water vapor) in the tropics. I have been asking this question for two years now, and nobody even attempts to answer it…

]]> By: John V http://www.opentemp.org/main/2007/12/03/is-it-possible-for-a-small-amount-of-co2-to-warm-the-earth/#comment-240 John V Thu, 06 Dec 2007 21:29:55 +0000 http://www.opentemp.org/main/2007/12/03/is-it-possible-for-a-small-amount-of-co2-to-warm-the-earth/#comment-240 #9 Michael Smith: As far as I know, 3.7W/m2 was established from numerical simulations. Wikipedia has a list of radiative transfer codes: http://en.wikipedia.org/wiki/List_of_atmospheric_radiative_transfer_codes MODTRAN has a web interface here: http://geosci.uchicago.edu/~archer/cgimodels/radiation.html #9 Michael Smith:
As far as I know, 3.7W/m2 was established from numerical simulations. Wikipedia has a list of radiative transfer codes:
http://en.wikipedia.org/wiki/List_of_atmospheric_radiative_transfer_codes

MODTRAN has a web interface here:
http://geosci.uchicago.edu/~archer/cgimodels/radiation.html

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