Global Warming...New Report...and it ain't happy news

Okay, for us thermodynamically challenged, could you put that into layman's terms as to what happens to the heat that is released when water freezes or becomes colder?

Foxfyre wrote:

Okay, for us thermodynamically challenged, could you put that into layman's terms as to what happens to the heat that is released when water freezes or becomes colder?

It is probably more accurate and intuitively satisfying to say that melting ice requires that heat be transferred to it from its surroundings. Heat flows only in the presence of a difference in the temperatures of source and sink. Heat can be transferred by (1) Conduction from objects in direct contact (this is basically the transfer of energy from molecule to molecule in collisions); (2) Convection from a flowing stream of liquid or gas in direct contact (the flow in effect transports heat to the boundary); Radiation, which involves the flow of photons from the hotter object to a cooler one (it is the heat you feel when you put your hand a few inches above a lighted stove, or near an incandescent light bulb -- broiled foods are cooked by radiation as are those in a microwave oven.)

So the melting of the Antarctic ice requires that it be in direct contact with air or water at a temperature above the local freezing point. Heat flows from the warmer air or water to the ice during the melting. As a result the air or water cools. Generally there are convective flows of the air and water around the ice which effectively replenish the thermal energy in the air/water in contact with the ice. If an equilibrium is reached the ice stops melting.

In dry, clear air with intense sunlight ice can sublimate directly from a crystalline state to vapor due to intense radiation heat transfer. You likely see this in the Rocky Mountain area quite frequently.

But okay. I recently asked a question related to a NASA graphic showing that the large land mass of Anarctica was getting colder and the ice thickening--while the surrounding perimeter of Anarctica was shown as getting somewhat warmer.

Now when I was growing up amongst fruit and vegetable farmers, they sometimes used large tubs of water or ran water into the irrigation ditches just before a predicted freeze. The theory was that the water would emit just enough heat as it chilled and froze to keep the tender blossoms from being destroyed.

Now my question was that if the vast interior of Anarctica is cooling, doesn't the heat that was there have to go somewhere? And would the logical place for it to go be around the perimeter which could explain temporarily slightly higher temperatures? And if this is so, then could this be an alternate explanation and the whole phenomenon does not necessarily have to be caused by global warming?

Foxfyre wrote:

But okay. I recently asked a question related to a NASA graphic showing that the large land mass of Anarctica was getting colder and the ice thickening--while the surrounding perimeter of Anarctica was shown as getting somewhat warmer.

Your problem here is that you are implicitly assuming there is no convective flow of air or water that physically transports the heat - or, alternatively, isolates some regions. In addition, you are ignoring the effect of radiation heat transfer, which at the poles generally involves enormous transfer of heat from the earth to space during winter nights. It is entirely possible for the southern oceans to be slowly warming (or melting) the perimeter of the Antarctic ice, but still fail to add enough heat by conduction & convection to the Antarctic core to make up for the losses due to direct radiation to space. There is a strong and enduring 'Antarctic cyclone' flow of air around the southern pole in the winter months. This effectively insulates the polar region from convective heat transport from lower latitudes.

Foxfyre wrote:

Now when I was growing up amongst fruit and vegetable farmers, they sometimes used large tubs of water or ran water into the irrigation ditches just before a predicted freeze. The theory was that the water would emit just enough heat as it chilled and froze to keep the tender blossoms from being destroyed.

Remember that the farmer was just trying to sustain his crops through a few hours of freezing temperatures at night. Water is much denser than air and retrains a good deal of heat. It can slow the nocturnal cooling of the crops as long as the wind velocity is not too high. High winds in effect replenish the heat absorbing capacity of the cool night air.

Now my question was that if the vast interior of Anarctica is cooling, doesn't the heat that was there have to go somewhere? And would the logical place for it to go be around the perimeter which could explain temporarily slightly higher temperatures? And if this is so, then could this be an alternate explanation and the whole phenomenon does not necessarily have to be caused by global warming?

The principal heat loss at the polar core is by radiation to outer space. The southern oceans and the atmosphere are continuously adding heat to the Antarctic ice pack, and the ice pack is continuously giving up heat to outer space by radiation. Radiation heat transfer is proportional to the difference in the fourth powers of the absolute temperatures of the source and the sink. On the absolute temperature scale, the Antarctic ice is at a temperature of about 260 degrees Kelvin and the night sky is at an equivalent temperature of about 200 degrees Kelvin. The difference in the fourth powers of these numbers is very large.

The United States already is responsible for roughly one-quarter of the world's carbon dioxide and other "greenhouse" gases that scientists blame for global warming.
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http://www.huffingtonpost.com/huff-wires/20070303/global-warming

Yes I do know this and I know it only works when the surrounding air is relatively still. But the principle could not also work on a hugely larger scale; i.e. the enormous land mass of anarctica? The length of time comparatively of the warmer perimeter might be proportionally as temporary as a farmer trying to help his peach blossoms survive a frost?

The United States already is responsible for roughly one-quarter of the world's carbon dioxide and other "greenhouse" gases that scientists blame for global warming.

The United States already is responsible for roughly one-quarter of the world's carbon dioxide and other "greenhouse" gases that scientists blame for global warming.

Hmmm. How is CO2 that is generated by my Subaru any different from CO2 that is generated by a rain forest?