Friday, April 3, 2009

A Layman's Guide to Climate Models - Part II

In my last post, we laid some ground work, provided key definitions and explained why models are not evidence. In part two we will look at some typical components of GCMs used to produce the findings oft cited as evidence by AGW proponents. My comments are general in nature and may not apply to all climate models for each particular component. Where it appears the case that a component does share commonality across models, I will make that statement. While I will not provide code or equations from models here, I will reference the Intergovernmental Panel on Climate Change (IPCC) averaged values where appropriate.

Climate models are complex mathematical approximations of the climate system. The models are complex, but the system is even more so and more importantly, the system is not completely understood. The graphic below shows the system as we currently think we know it1. Which components are the most powerful? Let’s look at some of the components as described by this IPCC graphic and how they are treated in most of the models referenced by the IPCC.

The Sun.       It’s the largest force in our solar system. The magnitude of how important the sun is a climate forcing should be obvious. Why then, is the sun given so little weight in most climate models? One need only look at the table of contents in Chapter 2, AR4 to see how little importance is assigned to the sun2.

There are at least three major components of the sun’s interaction with our planet and yet the GCMs address only one, solar irradiance3. Even within the solar irradiance context, the models do not address the full spectrum, concentrating instead on what we believe to be the most powerful, namely Ultra Violet (UV) radiation. We’ve only had the ability to measure components of the sun’s influence with any accuracy for about thirty years, during which time we’ve been experiencing a solar maximum which happens to correlate with the most rapid rise in temperatures in the last century.

The other two major components are solar winds and the sun’s magnetic field. Neither of these components are addressed in any GCM referenced by AGW proponents and the IPCC4. They are not addressed because they are not fully understood. It is thought that the solar winds protect the earth from cosmic rays, which in turn are thought to affect cloud formation, which in turn affects how much the sun heats the earth, which in turn affects climate5. Solar winds are greatest during solar maximums, of the kind that occurred during the last 30 years or so when temperatures rose “alarmingly.” The sun’s magnetic properties, while understood to be large, are not understood.

The sun is the largest force in our solar system, the primary driver of our climate and we do not fully understand it6. Yet the IPCC and AGW proponents assume it away or minimize it in GCMs. Parts of the sun’s influence cannot be modeled precisely because we don’t understand it and yet AGW proponents swear by the accuracy of their models.

Cosmic rays.       As powerful as our sun is, there are forces coming into the solar system from deep space that can also alter our climate. Note that cosmic rays are not mentioned at all in the graphic cited above. Our knowledge of cosmic rays is even sketchier than our solar knowledge and we’ve only just begun to measure cosmic rays in the last fifty years. The current theory about cosmic rays is that they influence cloud development7. We have zero understanding about any other impacts of cosmic radiation. Cosmic radiation and its impact on cloud cover is completely ignored in GCMs.

Clouds.       Not all clouds are created equal. Some, laden with moisture (H2O vapor), have a warming effect. Others reflect solar radiation back into space, therefore reducing the heating effect of solar radiation. None of this is well-understood with any certainty. A fact admitted by the IPCC. Cloud affects have one of the largest uncertainty factors in any climate models. Climate models as addressed by the IPCC display huge uncertainty as to cloud affect and that a effect is both minimized and assumed to be entirely a cooling forcing.8

The Oceans.       The ocean is the largest heat reservoir in the climate system.9 The oceans affect global surface temperatures and weather through the interactions of the Pacific Decadal Oscillation (PDO)10, the El Nino Southern Oscillation (ENSO)11, and the Atlantic Multidecadal Oscillation (AMO)12 as they switch between warm and cold phases. As the names imply, all are cyclical. While we have good knowledge of how long these cycles last, we have no idea what switches them between the phases. When all three are in their cold phase, global temperatures drop. When all three are in their warm phase, global temperatures rise. During the peak temperatures of the late 1990’s, all three were synchronized in their warm phase. At the moment, two of the three Oscillations have switched to the cold phase. The AMO is currently in warm phase, but due to switch in the next year or so. The AMO has the shortest cycle, roughly 5 years. These cycles are not addressed in most of the 23 models referenced by the IPCC.

Greenhouse Gases (GHG).       The most commonly referenced GHG include: H2O vapor, CO2 (natural and anthropogenic), CH4 (natural and anthropogenic), NO2 (natural and anthropogenic), and halocarbon gases (anthropogenic), and ozone (natural and anthropogenic). Together these gases make up less than 5% of the atmosphere.13

According to the IPCC, water vapor is the most abundant and important greenhouse gas in the atmosphere.14 Water vapor constitutes about 96% of all so-called GHG. And yet the models and the IPCC largely ignore this, instead focusing on CO2 as the main culprit in climate change.

CO2 currently accounts for about .0385% of the atmosphere. That’s decimal-ZERO-three-eight-five percent of the atmosphere. The models assume a high sensitivity in the climate to increasing amounts of CO2 in the atmosphere. The models assume a virtually linear cause and effect. And yet, looking at the graph below, it becomes readily apparent that temperatures do not necessarily go up with CO2. If we are agreed that CO2 has increased steadily since the start of the Industrial Age, then how do we account for the drops in temperature during the same period? Something caused the drops and obviously whatever it was, it was more powerful than the CO2 increase.

We are currently in a period of declining temperatures, during which CO2 has continued to rise. (Depending upon the source and adjusting for the 1998 El Nino event, temperatures have declined or remained flat for the past seven to ten years.) Not a single model predicted the current temperature decline. All the models and the IPCC predicted a continuing linear temperature increase. It hasn’t happened. Again, something more powerful than CO2 is in play.

Even the term “greenhouse” is questionable. A recent paper by Professors Gerlich and Tscheuschner points out the false analogy of a glass greenhouse in relationship the concept of an atmospheric greenhouse effect. They point out that such a concept violates fundamental laws of physics and thermodynamics.15 Yet the entire greenhouse concept is central to GCMs.

Notice that we did not even address feedbacks. These can be positive or negative and yet they are not well-understood and generally ignored in GCMs. Indeed the way the IPCC and models ignore away water vapor as an RF is to declare that it is a feedback. Hence it is not a component of most models. We can be free to focus on CO2.

We also did not discuss how these components interact, nor did we discuss any of the other components that influence climate. When you look at climate arguments, look for references to “the models.” Virtually all references to “studies” are in relation modeled results, but models are not in the real world. Models exist in a mathematical virtual world which does not operate under the same parameters as the real world, the world we actually live in.

The models predicting climate catastrophe rely heavily on calculated anomalies (models) as the primary source of almost real-world data. The anomalies are influenced by some of the climate components we discussed above (and a major one not discussed, namely Urban Heat Island effect). This makes reliance on climate models somewhat circular logic and that is why models are not evidence.


1. IPCC Assessment Report Four (AR4), Chapter 1 (Historical Overview
    of Climate Change Science), page 104, (2007).
2. IPCC Assessment Report Four (AR4), Chapter 2 (Changes in Atmospheric
    Constituents and Radiative Forcings), page 130, (2007).
3. IPCC Assessment Report Four (AR4), Chapter 2 (Changes in Atmospheric
    Constituents and Radiative Forcings), page 192, (2007).
4. Nigel Marsh, Henrik Svensmark, Danish Space Research Institute, (Solar     Influence on Earth’s Climate, Space Science Reviews,
    Vol 107), pp 317 – 325, (2003).
5. Ibid.
6. Ibid.
7. Henrik Svensmark, Influence of Cosmic Rays on Earth’s Climate,
     (The American Physical Society, Physical Review Letters,
    Vol. 81, Number 22), pp 5027 – 5030, (1998).
8. IPCC Assessment Report Four (AR4), Chapter 2 (Changes in Atmospheric
    Constituents and Radiative Forcings), page 205, (2007).
9. Levitus, S. J. I. Antonov, T. P. Boyer, and C. Stephens, 2000.
      Warming of the world ocean. Science 287:2225-2229. and
      Levitus, S. J. I. Antonov, J. Wang, T. L. Delworth, K. W. Dixon, and
     A. J. Broccoli, 2001. Anthropogenic warming of earth’s climate system.
     Science 292:267-270.
14. IPCC Assessment Report Four (AR4), Chapter 2 (Changes in Atmospheric
    Constituents and Radiative Forcings), page 135, (2007).
15. Gerhard Gerlich, Ralph D. Tscheuschner; The Falsification of
    The Atmospheric CO2 Greenhouse Effects Within the Frame of Physics;
    International Journal of Modern Physics B, Vol. 23, No. 3
    (30 January 2009), 275-364.

1 comment:

PaulM said...

JL, these last two posts are an excellent summary, and deserve some favourable comment. The key points are -
* We really don't know what the main factors driving the climate are, so modellers have to make assumptions about this.
* Even if we knew the main factors, we don't know the parameters, like the infamous feedback parameter, so assumptions about these have to be made.
* Simplifications have to be made in the model, for example convection in the atmosphere is not handled correctly if at all.
* Even if we knew the physics and the parameters, the equations are too complicated to solve so they have to be fudged to fit on a coarse grid.
The bottom line is that nothing meaningful comes out of these models. Whatever preconception you have, you can cook up a model to give the answer you want.