Heat is not temperature - it is possible for hot objects to have a small amount of heat and vice versa. It just depends on what the object is made of.

Heat is measured in calories (joules in the SI system), temperature in degrees Kelvin.

For each type of material, there is a constant - called Specific Heat - that relates the amount of heat to the temperature.

When a substance changes phase (solid to liquid, liquid to gas, and the reverse of each), heat is absorbed (or released) with very little change in temperature. This is termed "Latent heat of ..." and is sometimes referred to as enthalpy.

As a result, a substance like water has 6 different "Specific Heat" and "Latent Heat" values

Ice	Solid	Specific Heat of ice
Melting	Solid to liquid phase transition	Latent heat of fusion (melting)
Water	Liquid	Specific Heat of water
Evaporation	Liquid to vapor phase transition	Latent heat of vaporization (evaporation)
Vapor	Gas	There is no constant for this - steam tables are used instead
Sublimation	Solid to vapor phase transition	Latent heat of sublimation / enthalpy of sublimation

Physics books generally cover 3 ways that heat moves

Conduction	When a metal spoon is placed in boiling water the handle tends to get hot. In this case, heat flows through the metal by conduction. If you use a wooden spoon, the handle stays cool. This indicates that metal is a better conductor of heat than wood.
Convection	Basically, this means that hot things rise and cold things sink.
Radiation	Heat can travel as Infrared (IR) radiation - the slowest of all the heat transfer methods. This is how heat from the sun reaches the Earth, and how the Earth releases the same heat, plus a little more (from the liquid core), back into space.

In the real world, these methods are also important

Phase change	When you boil water, the temperature does not change. It does not matter how much more heat you add, the temperature stays the same as the water converts to steam. When a cloud forms, the water vapor looses heat.
Transport	In the old days, some people would heat rocks in a fire and then place the rocks in a pot to cook the food. Today, we heat water in a tank and transport it (via pipes) to the shower. The Jet Stream, weather fronts, the Gulf Stream, and the like move tremendous amounts of heat from one area to another.
Chemical Change	A battery stores energy via chemical change. Leaves convert energy (Sun light) into sugar.
Mixing	Stirring a pot will keep the bottom from burning. Physically mixing fluids of different temperatures moves heat faster than simple convection.

Consider a hollow metal tube with both ends sealed. Inside the tube are a few drops of some liquid. As heat is applied to one end of the tube, the liquid vaporizes. At the other (cool) end, heat is loss and the vapor condenses back into the liquid phase. In the simplest configuration, the hot end is placed below the cold end so that gravity will pull the liquid back down. Other configurations exist.

Depending on the working temperatures, water, alcohol, freon, sodium, and many other materials can be used as working fluids. The only requirement is that the fluid must be liquid at the cool end and vapor at the other.

Most laptop computers contain heat pipes because there is not enough space for air to blow over the components. (My laptop has 2 - one for the processor and another for the video chip.)

The fact that air at the surface is usually warmer than the air above it helps - but it is not always necessary.

At some point, the expansion cools the rising air mass to the point where water begins to condense (forming clouds). Since the energy released is equal to the heat of vaporization, heat has been moved from the surface of the planet to the top of the clouds. At this point, the clouds act like mirrors reflecting the heat out into space.

Note - if the heat was released inside the cloud, it would simply be reabsorbed by the surrounding water droplets causing them to return to the vapor state. Therefore, the vapor *effectively* condenses only at the top of the cloud.

To complete the cycle, the condensed water returns as rain (or snow).

Even though there is no confining tube, I have described this cycle as an Atmospheric Heat Pipe because of the obvious similarities. These heat pipes are not the only way that the Earth cools itself - but they are the most efficient.

The model described here provides one mechanism for heat to move around the additional CO2.

Think of it this way

• The Earth is hot and surrounded with an insulating blanket of atmosphere
• The atmosphere is heated by
  • Conduction - the air touches the surface and gets hot
  • Radiation from the surface - Water, CO2, and methane absorb some of this heat. With a few exceptions, the rest of the atmosphere is transparent to IR radiation.
• At this point, both the atmosphere and the surface are trying to radiate heat into space.
• Note that the atmosphere is a very poor radiator because the radiation goes in all directions and, therefore, some of it returns to the surface and some is reabsorbed by the atmosphere. This is actually how the atmosphere helps to insulate the planet.
  • It is heated mainly by conduction
  • The heat is spread out via mixing - convection and wind
  • Radiation to space is very inefficient
• Radiation from the surface of the planet is more efficient because it is less likely to be reabsorbed
• Radiation above the clouds is the most efficient because it has less atmosphere between it and space ... and all of it is radiated upward

The Atmospheric Heat Pipe model presented in this page provides a very efficient mechanism to bypass this problem.

Of course, wind, weather fronts, and storms greatly complicate this model. My point was simply to show that simple evaporation followed, by cloud formation, effectively pokes a hole in the insulating atmospheric blanket so that heat can escape. As a result, if additional CO2 makes this blanket more efficient at holding heat, that will have almost no effect because the water driven heat pipe (phase change assisted heat transfer) will provide the necessary negative feedback.

One prediction of this model is that adding CO2 to the atmosphere will actually increase the amount of rainfall.

Note - Many Global Warming predictions include more storms AND expanding deserts - talk about covering ALL the bases.

Please, don't just read the few quotes I've included below - read the entire section. It is painfully obvious that none of the models are very good ... and clouds are almost ignored.

7.2.2.4 Cloud-radiative feedback processes

In response to any climate perturbation the response of cloudiness thereby introduces feedbacks whose sign and amplitude are largely unknown.
...
The sign of the cloud cover feedback is still a matter of uncertainty and generally depends on other related cloud properties.
...
Cloud optical feedbacks produced by these GCMs, however, differ both in sign and strength.

7.2.2.5 Representation of cloud processes in models

In spite of these improvements, there has been no apparent narrowing of the uncertainty range associated with cloud feedbacks in current climate change simulations. A straight-forward approach of model validation is not sufficient to constrain the models efficiently and a more dedicated approach is needed.

Note - This section has a graph showing which models consider clouds as positive or negative feedback mechanisms.

7.2.3 Precipitation

... the associated heating rates often dominate all other effects and strongly influence local and global circulations.
...
These aspects have been explored only to a limited extent in climate models. No studies deal with true intensity of rainfall,
...
However, estimates of precipitation and surface long-wave radiation suggest that the sensitivity of the hydrological cycle in climate models to changes in SST may be systematically too weak. Accordingly, it is important that much more attention should be devoted to precipitation rates and frequency, and the physical processes which govern these quantities.

The Atmospheric Heat Pipe I've presented above provides a major negative feedback mechanism that works to reverse any possible effects from increased CO2 - however, some climate models actually consider the feedback to be positive.

Note - Positive feedbacks will make a little heating get even hotter and negative feedbacks tend to make temperature changes very difficult.

I don't believe that there is enough evidence to believe that Venus is hot because its atmosphere is mostly CO2 - but those arguments will be discussed elsewhere. In the meantime, consider this

It can be argued that the main reason that Venus is so hot is because there is no mechanism to rapidly move surface heat above the cloud layer. As a result, it does not matter if the atmosphere is mainly CO2 or not, the planet is hot because the atmosphere does not contain a substance that is liquid at surface temperatures and condenses to form clouds above most of the atmospheric mass.

URL: http:// questionable-science.com / Global_Warming / Heat.html