Global Warming and Phase Changes

By Frank Levinson, Guest Author

There are so many articles today about global warming. Its potential impact, our responses, the threat to our future and all of them fail to give us a simple statement of what is going on. Al Gore tried in his recent Oscar-winning film … now it is my turn.

In spite of all the press, there remain very active groups and articulate individuals who believe it is all a hoax, or that it is based on bad science, or that it will not be harmful. It is possible that the President of the US is even one of these people. Beyond those who simply think it false, there is a larger group who are confused about the arguments and reasoning that supports the conclusions today of nearly every scientist.

Examples of the confusion come from otherwise very connected, smart and conscientious individuals. Here are some quotes –

* A Silicon Valley VC said, “I have been swimming in the ocean in the same place, and there is a water pole that I stand next to and the water rises to the same place on my body now as when I was younger by 30 years. The ocean is not rising.”

* A CFO of a public company cites evidence from the web that there were more greenhouse gases released from Mount Pinatubo than by man and that did not change the climate.

* A famous novelist now is helping the current US President refute the evidence for global warming, citing dozens of sources for conflicting evidence.

* This winter (2007) was remarkably warm until February, when brutal cold and massive snowstorms arrived. As the snow in upstate New York passed 10 feet in just a couple of weeks, people were heard to say, “This should not happen if global warming is occurring.”

It is my firm, studied belief that global warming is happening and that its source is predominately human activity that is causing a build up of greenhouse gases (mainly C02). And that it will be one of the defining elements of our collective human future. But the reason it is not so obvious to many thoughtful individuals and so many more who generally ignore the debate is that the evidence they think they should see is not what is presented. In other words, they equate global warming with significant and consistent temperature rises. That is not the right evidence because the earth’s ecosystem is a buffered system.

The increased heat the earth has accepted and retained is not going into temperature increases so much as it is being used to melt ice.

Warming and temperature increases are not actually connected so long as the earth has substantial amounts of ice. And this statement is counterintuitive to nearly all of us.

What? Warming and temperature not connected? Exactly.

The key to understanding this requires an explanation of how water changes from

Solid? Liquid? Gas?

You know these three states of water as ice, water and steam, but in a normal kitchen these can exist side by side in close proximity. And they do so in nature, too. The change from ice to liquid water is called a “phase change”. The phase change from ice to water and from water to steam has been extensively studied and measured, and today is pretty well understood.

You may remember from some chemistry or physics class that a small amount of normal liquid water, a cubic centimeter or 1 cc, will rise 1 degree centigrade in temperature if you add to it 1 calorie of heat. This applies if the water is room temperature, just above freezing or close to boiling. So to raise 1 cc of liquid water that is just above freezing to just before it boils takes 100 calories because there are 100 degrees centigrade between these just melted and just boiling water points.

But to raise the same amount of water from just below freezing (from when it is ice) to just above freezing, a change of only 1 degree requires 80 calories!! Or nearly as much heat as the entire temperature rise from 0.1C to 99.9C.

The same general principle applies to water when it changes from liquid to gaseous steam. Again, a temperature increase of only 1 degree requires vast amount of energy to accomplish (in this case about 540 calories).

This principle is why if you have a glass of ice water for dinner, it stays the same temperature throughout a long meal so long as there is ice to melt. It is the melting of the ice that keeps all of the water in the glass pretty close to the freezing temperature. Clearly heat is flowing into the glass of water, but the temperature is not changing. If you do not believe this, then hold a glass of ice water until all of the ice melts. You will get colder, but the temperature of the water in the class does not appreciably rise. The “warming” of the glass of ice water, “the system” in this case, happens by taking the warmth from your body and it uses this measure of energy to melt the ice first and then to further change the temperature of the water after the ice is melted.

So you see, if the earth has large quantities of ice in some places then we might not see any real temperature change either as global warming occurs; just like the glass of ice water’s system, the earth’s system has both water and ice in large amounts so as things are “warmed”, first the ice will melt and in doing so it will undergo a “phase change” and this involves the adsorption of large quantities of heat in exchange for the phase change from ice to water.

And because of this, our land and seas have remained relatively stable for very long periods of time. It is why it is hard to have an “ice age” and why global warming may be happening but the average person cannot see the effects. The earth has remained a remarkably stable environment for water-based life because it is a buffered system wherein imbalances of energy (an excess will cause warming and a deficiency will cause cooling) on short term bases are insulated from becoming inadaptable temperature changes; instead ice either forms or melts (and water evaporates or condenses) and massive amounts of energy can be exchanged in either direction by the change from water to ice or ice to water. What primarily makes our climate is the global interaction between water and land temperatures and these have not changed over most of the earth very much.

What has changed?

Well, we do know that globally ice is melting on an unprecedented scale, for example –

* Mt. Kilimanjaro has had a beautiful snow-capped peak in the collective memory of all humans who have seen it in Africa. But in the next few years all of the snow and glacial ice will be gone.

* The glacier that is part of the tallest mountain in Europe, Mt. Blanc (the pen company is named for it), used to allow the sheep to cross it to summer pastures 120 years ago. But even 20 years ago, the tourism industry in France built a chair lift to ferry people who were unable to do the difficult walkdown to the glacier. Today, that chair lift is another long walk and perhaps 50 feet (15 meters) away from the glacier where it very recently nearly touched.

* Glacier National Park in Montana will likely have no more glaciers in the next 20 years.

* Large chunks of Antarctica and Greenland ice have broken off due to melting.

And so we know that it is likely that massive amounts of heat are being absorbed in the phase change conversion of solid water to liquid water, ice to water. And there is sufficient ice for many years to come. So the alarm bell of global warming will for years seem like hype because the reasons given above will continue to apply.

But what happens when ice is gone from some area or from the Earth generally?

That is the question we need to consider.

The simple answer is that the level of the ocean will rise and the saltiness of the ocean will fall a bit. But this will happen very slowly.

But what will happen quicker is that as ice melts, we will have more places where there has been ice for millennia, and quite suddenly there will be no ice. And I wonder if the melting of ice in locations during hot dry times has been a shelter to some animals or plants? Did the ice build back up other times in these places and diminish in some cycles that we don’t see? Because this time, we cannot anticipate the ice being rebuilt in our lifetimes, nor those of our children or grandchildren.

Kilimanjaro, Glacier National Park and other places when they lose their ice this time will remain ice-free. The storage of water as ice there will end and the buffering of temperatures thereby, at least, locally stored ice will be gone. I do not believe we understand the impact of this on any of these places.

The most prominent phase changes we all can see is that of ice to water to steam. But are there other changes that are also “phase change-like” in their nature?

The answer is certainly yes.

Water itself has two phase changes. The first we discussed. The second is from liquid water to water vapor or steam. This phase change occurs when a glass of water sits on a counter for a couple of days and the water slowly disappears or when you put a pot of water on the stove and heat it up so that it boils. In this latter case, you can see the immense amount of energy this phase change also requires because the moment you shut off a gas flame on the stove the boiling process stops. Changing 1 cc of water from liquid to gas takes about 540 calories. Again a big number when compared to simply changing liquid water 1 degree warmer.

This second phase change of water also helps buffer the earth’s ecosystem. As we warm up, more water will be cycled through our atmosphere. This may be what is causing more frequent and more violent hurricanes; but this is not certain or scientifically confirmed.

But I think that there are other phase changes that are occurring on the earth that are driven strongly by human activity. Changes that consume vast amounts of energy to happen and once they happen will be most difficult to reverse.

Consider the change from rainforest to farm/grazing land and then from farm/grazing land to fallow or desert land. This has also happened in our lifetime more frequently than many of us know. In this case, the land goes from biodiversity rich to biodiversity poor to, in some cases, virtually dead. And it also takes energy to make these changes. The forest must be cleared (often by burning), the previous vegetation suppressed (often chemically), and then energy is used to restructure and reshape the land for its new use.

In the case of the land change from farm to desert, this often happens because the land under the rainforest was not nutrient-rich enough to be sustainably farmed for very long, and so the farmer, having depleted the land, moves on and clears additional forest and abandons the land. In this state, it will degrade through erosion and through periods of drought and may lose its long-term ability to support rich and diverse life forms. Forests are long-term holders of carbon and water and support biodiversity on a scale that fallow land cannot.

In the end, I wonder if for every person who believes that global warming is not happening and that humans are not the dominant cause of it, what makes them so certain. I wonder if they were asked how they know the Earth is a sphere in the cosmic void that spins on its axis and orbits the sun so that we are all moving at tens of thousands of miles per hour. Why is it that they believe this more than global warming?

You cannot feel the Earth’s rotation, nor its orbiting about the sun. You cannot feel the solar system orbiting around a massive black hole at the center of our Milky Way galaxy. But I do think that these are “facts” that are generally believed by many people in the US and other first-world countries. The only difference is these astronomical facts do not drive the need for much change in the average person’s behavior.

The answer could be that they believe the pictures of Earth from space in this instance. That they believe the physicists, astronomers and those in government in this case but not in the case for global warming. For the personal, physical evidence is, in practical terms, the same level of believable in both examples.

How do we assign believable truth in our modern society? And how do we understand it quick enough to be able to use the scientific wisdom to make decisions that can make a difference in our future?

It is clear that we cannot use our ordinary physical senses to help us sort this out. And so we must find ways to separate fact from fantasy and to then trust even when we cannot sense personally one way or the other about the decision.