The effect of water vapor on global warming

One of the false arguments global warming deniers make is that CO2 measurements are unimportant because water vapor is much more effective greenhouse gas. This is one of those statements that has just enough truth behind it to obscure the lie.Yes, water vapor is a very potent greenhouse gas, much more so than CO2, but what the deniers don’t want to admit is that the reason there is water vapor in the atmosphere is because something else warmed it up in the first place.

This process makes water vapor a positive feedback agent with the potential to approximately double the amount of warming due to other sources. As the atmosphere gets warmer the amount of water vapor in the atmosphere also increases. The increased level of water vapor will then trap more heat, resulting in warmer temperatures and even more water vapor. But, the water vapor cannot do it alone. There must be some agent to start the process and that agent in our current situation is CO2. By dumping billions of tons of CO2 in our atmosphere every year, we trap heat in the atmosphere that would otherwise radiate into space and this leads to warmer atmosphere. This warmer atmosphere then leads to more water vapor.

Since water vapor is so important in the process we need to know just how much effect it has on the climate. A team of scientists used measurements from instruments onboard the Aqua spacecraft to make direct measurements of this effect. According to their work, water vapor amplifies global warming by 2.2 watts per square meter per degree Celsius (plus or minus .4 watts per square meter per degree Celsius). In comparison, the solar index (the amount of energy reaching Earth from the Sun) is about 1360 watts per square meter. For every one degree Celsius change in temperature, water vapor increases the amount of energy stored in the atmosphere by about .16%. It may not sound like much, but you keep doing that every day for a long period of time and it will add up to a very large amount of energy stored in the atmosphere that we would not otherwise have.

The scientists point out that this is only a short-term measurement because the amount of data is small. This figure is subject to short-term changes in the weather and climate fluctuations. They used these figures in models to try and determine a long-term value and the models suggested it is between 1.9 and 2.8 watts per square meter per degree Celsius. As more data is collected this figure will be refined to a more accurate value.

Thoughts on Climate Armageddon

I am an advocate of manmade global climate change, and have been for a long time now. I was first convinced of the scientific validity of this in the mid-1980s. Every day since then has reaffirmed my scientific belief.

At the same time, I have stood fast against alarmist predictions. I have a hard time seeing the validity in them and feel they work against the effort to convince the public and politicians that we need to take action now.

I read today an article on scientificamerican.com that I think perfectly illustrates the point. This article was adapted from the book, “The Fate of the Species: Why the Human Race May Cause Its Own Extinction and How We Can Stop It,” by Fred Guterl. Fred Guterl is not some light weight. He is the executive editor of Scientific American and has been doing science reporting for over 25 years. However, despite his credentials, Mr. Guterl is wrong in this article and I will show you why I say so. I have not read the entire book, so I will not comment on it.

The article focuses on nine ‘tipping points,’ as defined by climate scientist Tim Lenton at the University of East Anglia. Dr. Lenton identifies tipping points as a combination of factors that could lead to a sudden change in dynamic factors. In the case of the climate, these tipping points, he claims, could result in a change in the climate occurring in a matter of a few years or even a period of a few months. I do not dispute that each of the tipping points is a cause of concern. What I dispute is the idea that these might result in a catastrophic change in the climate over a short period of time.

Let me briefly summarize these tipping points:

1. Failure of the Indian Ocean monsoons. This is caused by the combination of pollution in the air that causes the monsoons to weaken and global warming which causes the monsoons to get stronger. The result is a kind of balancing act that could rapidly change the monsoons.

2. Failure of West Africa monsoons. The same as the Indian Ocean monsoons, except applied to the monsoons of West Africa.

3. Loss of Arctic sea ice. He postulates that as the summer ice sheet continues to get smaller and thinner it could eventually result in a year-round ice-free Arctic Ocean. This would result in continuous warming and a change in the ocean currents.

4. Collapse of the Greenland ice sheet. The ice sheet could collapse much more quickly that predicted (by a factor of 3 times faster), resulting is dramatic sea level rises worldwide.

5. Altering of the North Atlantic ocean currents. The change in fresh water in the North Atlantic Ocean due to the melting of the Arctic ice sheets and the Greenland glaciers will cause the dynamics of the North Atlantic currents to alter, greatly affecting the climate of Europe.

6. Collapse of the West Antarctic ice sheet. See the collapse of the Greenland ice sheet above, only much bigger.

7. Collapse of Amazon rain forests. Droughts get longer and more severe in the Amazon, leading to a change in the climate.

8. Collapse of Canadian boreal forests. Same thing, but with the Canadian forests.

9. Altering of the El Nino – La Nina Southern Oscillation. The Southern Oscillation drives much of the world’s weather. Global warming will result in changes to this oscillation and cause changes to the world climate.

So, there are the nine tipping points he mentioned. Like I said before, I don’t have any particular problem with this list, it is the time frame that I have the biggest concern with. To begin with, he defined a tipping point as something that occurred over a few years or even a few months. Some of these things, he states, will take hundreds of years to occur. That hardly fits the definition of a ‘tipping point’ that was put forth. Specifically, he estimates the melting of the ice sheets on Greenland and Antarctica will take about 300 years. In both cases, this is dramatically less than the more than 1000 years that is predicted for both. Still, 300 years is quite a bit of time. In comparison, the United States is only 236 years old this year.

Looking at numbers 1 and 2, the two about the monsoons. We are already seeing changes in the monsoons and this is an issue of great alarm. Well over 1 billion people depend on these monsoons for their livelihood and their food supplies. However, while we are certainly concerned with the idea of these monsoons changing, the scientific evidence does not support the idea that they may change dramatically, or even cease, anytime in the next few years. Could it happen? Possibly. And, we need to be concerned and work to prevent it. But, it is not something we need to worry about happening within the next few years.

Number 3 deals with the loss of the Arctic ice sheet. This is, once again, something of great concern. As the ice sheet melts the dark ocean will absorb much more sunlight than the bright ice that reflected much of it. However, the North Pole is in darkness six months of the year and the entire Arctic Ocean experiences lengthy, and cold, winters. It is not believable that the Arctic Ocean will be ice free throughout the winter in the foreseeable future.

I already mentioned numbers 4 and 6, concerning the Greenland and Antarctic ice sheets. Even if he is right, 300 years does not qualify as a tipping point. But, the change in the North Atlantic Ocean currents certainly does. This is one that he may be right about. In fact, one of the seldom discussed problems with the melting of the Arctic ice sheet is the fact that old ice is composed of fresh water. Ice slowly squeezes the salt out and so becomes more and more fresh as it ages. As this old ice is melting in the Arctic Ocean it is creating a large bubble of fresher water sitting on top of the ocean. There is concern that this bubble might be forced into the North Atlantic and we really aren’t sure what would happen if it does. Adding billions of tons of fresh water from the melting of the Greenland ice sheet will only make matters worse. And, what is all of that extra fresh water going to do to the currents around Antarctica?

Changes in the Amazon rain forest are already being observed. As the forest is chopped back, it no longer has the critical mass to affect the climate the way it use to. Already, we see that droughts are more frequent, more severe and last longer in the Amazon region. These droughts are causing trees to die, which will only make the situation more severe. There is no speculation on this. It is already happening. But, will it suddenly collapse in a matter of years? There isn’t anything to make me believe this is true. The Amazon is an area under great stress that we need to be actively working to save. But, I do not believe it will suddenly collapse in a matter of a few years.

All of this also applies to the Canadian boreal forests.

Number nine may or may not be valid. We are really learning a lot about the Southern Oscillation, but there is much we don’t understand. Could it suddenly change or disappear? Really, I don’t think we know enough at this time to say. But, neither does Dr. Lenton.

So, is there anything I see in this list that I am concerned with? Yes, every thing he listed is something I am concerned with. Do I believe these things will suddenly ‘tip over’? No, I really don’t think the time frame is that fast.

And, as I have stated before, none of this helps us. The public does not believe in a “climate Armageddon.” Claims like this tend to turn them off and make them think all scientists are alarmists. At the same time, I don’t ever want to be mistaken for someone that says we shouldn’t be concerned about these issues. We should. And, we need to start working on them right away. I just don’t believe that yelling ‘wolf’ is the best way to get people motivated.

Sooner or later, they won’t listen to you anymore.

Australia’s climate history displays the Hockey Stick

The scientific paper, “Evidence of unusual late 20th century warming from an Australasian temperature reconstruction spanning the last millennium,” published in the journal of the American Meteorological Society, reports the results of reconstructing the Australian climate for the last 1000 years. They used tree rings, cores from corals and ice cores to build the proxy record. This record was then used to help validate climate models. This reconstruction shows the same hockey stick pattern that has been routinely identified in the northern hemisphere. The researchers found the warmest pre-industrial revolution period occurred in A.D. 1238 – 1267, right in the period known as the Medieval Warm Period (MWP). The coldest period occurred between A.D. 1830-1859, at the end of the Little Ice Age. There was no period that matched or exceeded the period since 1950.
This study was interesting for more than the climate pattern. What they found was that they only way they could get models to reproduce this data was to include natural forcings, such as solar and volcanic activity. But, they also found natural forcings could not reproduce the observed warming period since 1950. They only way they could reproduce the data was to include manmade emissions of greenhouse gases.
The climate change deniers will spin this up some how, they always do and the gullible people will fall for their lies and false arguments. But, the data keeps piling up. Within the scientific community there is virtually no debate that manmade climate change is real. Over 97% of climate scientists and over 80% of all scientists in all fields agree that manmade greenhouse gas emissions are changing the climate.Within the scientific community the focus is now more on understanding the dynamics of climate change and trying to figure out what we can do about it. But, before we can really do anything we must overcome the skepticism the general public has and to soundly refute the climate change deniers. 
Research like this Australian paper will help. It is one more big piece of the puzzle.

New information tends to refine models

One of the criticisms made by climate change deniers is that ‘scientists don’t know everything.’ The premise of this is that as we learn more then what we thought to be true becomes false. In this particular instance, deniers claim that as we learn more we will learn there is no such thing as climate change. This, of course, is a totally false argument and there is a bit of recent research that illustrates this.

A new report came out showing how human use of water is contributing to sea level rise. This, of course, makes sense. We are pumping huge amounts of water out of aquifers and other land-based sources of water for use in agriculture, industry and for home use. Much of this water finds its way into the oceans, via one path or another. Measurements have shown this has added .7 mm/year worth of sea level rise.

Of course, deniers at this point will be going, ‘Ah, ha! See! You were wrong about those climate change claims!’ Actually, no. We were right and this study shows that. The problem has been that our calculations and measurements always came up with a shortage of about .7 mm/year in the sea level rise. When we did the calculations of sea level rise due to melting ice and thermal expansion our results were about .7 mm/year short of what was actually measured. There had to be an extra source for sea level rise that was not being factored in. Now, that source has been accounted for and the numbers add up very nicely.

The point of this is that the more we learn, the more we confirm and refine what we already know. And, the reason for this is simple. Any hypotheses or theory we come up with in the future must take into what we already know. We will not come up with a new theory that throws out everything we have already discovered. It may add a whole new dimension to it or change the way we look at things, but it will always include the discoveries that have already been made. It has to because those discoveries are properties of the natural world and the natural world does what it does with or without our understanding.

As we learn more and more about climate change the new discoveries are not going to refute climate change discoveries. They are rooted rock-solid in massive amounts of scientific evidence that is not suddenly going to go away. What we learn will merely refine what we already know and help us understand what is going on.

Those are the kinds of discoveries we need, ones that help us understand what is going on better.

Next Generation Climate Models

Climate change deniers like to attack the credibility of climate change models. One of the common charges is that ‘you can make a model do anything you want.’ In this way they are able to fool the public with a false argument.  The fact is, models must faithfully represent natural processes, or it isn’t a model. I cannot go out and generate some computer code that will give me a desired end result. That is not a model. If I am creating a model then it has to be something that follows the laws that govern what ever it is I’m modeling. In the case of climate change, this would be the laws of physics.

Research scientists creating climate models must write the laws of physics into their code. If done correctly, the researcher can then input a data set and the results will accurately reflect the consequences of that data set. Unfortunately, this is very difficult. The laws of physics on the scale of planetary climate systems is very complicated and has a large number of variables. The good news is that researchers have been working on these models for a long time and are very skilled at what they do. Each new set of models is more and more sophisticated and accurate. In fact, today’s climate models are becoming amazingly accurate and produce results that accurately reflect the world’s climates.  Models today have been able to reproduce past climate changes as well as climate features of today. 

It is important that these models are tested and compared with other models. This is called validation and is the process of determining just how accurate a model is.Obviously, validation is an extremely important step in modeling. We all need to know just how dependable a model is if we want it to be of any use. That is why climate models are subjected to some of the most rigorous validation of any models anywhere. There is a very good chapter on climate model validation in the latest IPCC report.

Deniers will point out that models are only so accurate and there is still some errors in them. These statements are true, but irrelevant. If we were able to model the climate down to the last atom on the planet, there would still be some errors. What the deniers don’t want you to know is that models give us results that are so accurate that we can now use them to make forecasts and their results can be reliably used in policy making decisions.

The real reason deniers don’t like climate models is that they consistently and repeatedly show the only way we can have the climate of today is if manmade emissions are factored in. Without gases generated by humans we would have a significantly different climate today. This is just more than the deniers can stand to hear.

But, work is always in progress and I noticed that the National Science Foundation is calling for proposals for new advances in climate models.

I’m sure the deniers will use this as a false argument with the claim that models are so bad the government is vainly trying to find people that can figure out a way to make a better one. Well, don’t listen to them. The models are good, but that is no reason to not want to improve them.