Originally Posted by The Rani

That is actually a good question. How to fight "religion as science" without resorting to "science as religion." I think that finding common ground would have to be the first step. There are a lot of things that people have in common, whether in red states or blue. Rather than beat someone into submission because you don't agree with their "worldview," how about trying to find these areas of agreement, and use them as a starting point in finding solutions?

You mean, like ah, we'd have to sit down, shoot the shit, muddle through the knowns and unkowns then actually compromise. Isn't breaking out the clubs easier?

Originally Posted by The Rani

So all you blue people, let's compromise, dammit!

"Blue people" . . . I have this sudden atavistic image of myself, naked and painted with woad, swinging a battle-axe. Unfortunately that's not very compromising.

We already established that we're basically in agreement here about what to do. Everything else is just the trimmings. I have this feeling that the new political consensus is going to consist of some parts blue, some parts red, the parts we can all agree on, with the other parts downplayed, and we'll all come across as purple people.

Not sure what kind of image to associate with those words.

Originally Posted by Brian Rush

"Blue people" . . . I have this sudden atavistic image of myself, naked and painted with woad, swinging a battle-axe. Unfortunately that's not very compromising.

We already established that we're basically in agreement here about what to do. Everything else is just the trimmings. I have this feeling that the new political consensus is going to consist of some parts blue, some parts red, the parts we can all agree on, with the other parts downplayed, and we'll all come across as purple people.

Not sure what kind of image to associate with those words.

Sounds a bit like a bad 1960s drug trip. Watch out for the Purple People Eaters and the Blue Meanies!

I can agree with the political evaluation, if not the images you are invoking.

Originally Posted by Bob Butler 54

Sounds a bit like a bad 1960s drug trip.

I KNEW it had to be coming from somewhere! Flashback! OMG my karma ran over my dogma!

Originally Posted by The Rani

Huh? This has been happening for years, and there are no lobbyists that I know of pushing for the illegalization of antibiotics as a necessary means of saving the planet. Same goes for teaching evolution in public schools.

One more point. "Theory of Evolution" implies past events, which is a lot different from observing genetics in action.

Climatology also deals with past events. Slow processes are hard to observe in the present. One has to try to learn from history, to get evidence from the past as well as from immediate observation. In fact, the two fields of climatology and evolution overlap in their evidence base. Strong climate changes result in extinctions. If one sees an abrupt temperature change and associated CO2 concentration shift, one also often sees an abrupt shift in the fossil record. From there, it is not a giant leap to saying 'those not able to survive the changing environment didn't pass on their genes.'

There are examples of genetics in action within a human lifetime. Evolution can be observed by the patient. I mentioned a superbug, essentially immune to modern antibiotics, that is found only in the US military's evacuation chain from Iraq though the VA hospitals in the US.

There was another study done of birds in the Galapagos Islands. In wet years, you get big nuts on certain species of trees, and the birds with big strong beaks capable of breaking such nuts thrive. In dry years, smaller agile beaks capable of reaching harder to get at nuts do well. The scientists monitored nut and beak size through several climate cycles of wet and dry, and found the bird population did evolve to a relatively quick stimuli.

Originally Posted by The Rani

Um, was that supposed to be a joke? I'd like evidence, please, not merely statement of opinion.

Still waiting.

I was wondering if your demand for proof was a joke.

What specifically do you want proven? I listed a number of basic fundamentals to climate science: greenhouse gasses (CO2, SO2, methane, etc...), solar variations, cosmic ray variations (spiral arms), orbital variations, glaciation, and dimming caused by soot particles are a list of forces that most acknowledge will effect climate. I thought I had gone over the broad principles of how most of them worked. Which fundamentals do you see as requiring 'proof'? Going through each of them one at a time would make for a very long post.

And which tools of the trade are you going to deny out of hand? I gather referencing computer models would be futile? This makes things awkward, as you don't only have to prove a given fundamental has an effect, but also look at a temperature change and allocate how much each of several factors may be effecting the change.

I just want to understand your personal rules of what consists of a 'proof' under your values. If you deny the value of the professional work, I'll end up hand waving at historical graphs, which isn't satisfactory in some ways, but might seem more satisfactory given your world view.

And if you deny the historical record, are not willing to look at the results of the glacial cores and similar historical records, I'd need to come up with a different set of proofs yet again. If evidence isn't evidence if you can't see it happening in real time in front of your eyes, I'm not sure what approach would be satisfactory in terms of 'proving' a process too slow to be seen with naked senses.

What are the rules satisfactory, given your world view? What hard data will you accept, and what will you deny? Which fundamental mechanisms will you accept, and which require proof in your eyes? Which tools of the trade will you accept, and which will you deny?

Originally Posted by The Rani

Let's take this question first ... what scientific evidence shows us how much global warming is caused by human factors, and how much is caused by others?

Evidence is in bold.

It is a fact that humans add CO2 to the atmosphere. This causes the amount of CO2 to rise in the atmoshere. A higher partial pressue of CO2 means a higher solubility of CO2 in seawater. Thus, some of this added CO2 is absorbed by the oceans. Not all of it of course, higher levels are needed to drive the greater solubility, and so the level of CO2 in the atmosphere should rise with time. Rising CO2 levels have been measured, confirming this mechanism.

Thus, that humans had added CO2 to the atmosphere (and continue to do so) and that the level of CO2 in the atmosphere is increasing as a result is a fact.

CO2 is a greenhouse gas. What that means is it aborbs IR radiation emitted from the Earth's surface and re-radiates some of it back onto the Earth. An increase in CO2 will result in an increase in the effective amount of radiation received by the Earth's surface. This increased radiation is called a forcing and calculations provide the following estimate for the forcing due to the CO2 greenhouse effect:

forcing (watts/sq meter) = 5.5 ln (CO2/CO20)

Here CO20 is a reference level. The forcing is calculated wrt to a reference level. For example currently CO2 is about 383 ppm while in 1950 it was about 312 ppm. Thus, relative to 1950 human-generated CO2 has produced a forcing of 5.5 ln(383/312) = 1.1 watts/sq meter.

The impact of this higher energy flux on the earth is obtained by mutiplying the forcing by a parameter lambda. A value of lambda of 0.3 can be calculated from the Stefan Boltzmann equation assuming constant atmospheric emissivity. Lambda of 0.3 with a 1.1 watt/m2 forcing gives0.33 degress C. The direct effect of human CO2 emissions (i.e assuming no feedback effects that change atmospheric emissivity) has been to produce a temperature rise of about one-third degree since 1950.

In addition to CO2, humans also produce another forcing, that due to injection of particulates into the air. Volcanos do this too. The forcings produced by both are negative. It is very difficult to estimate the amount of forcing produced by particulates. If the forcing of human-generated particulates were large enough the net effect of human activity could be negative. That is, the negative forcing from human-introduced smoke would be larger than the CO2 forcing.

However we now come to the additonal observation (measurement) of rising global temperature--nearly 0.5 degree since 1950. In other words, actual temperature has risen by nearly 1/6th of a degree over the value given above for human-generated CO2. We need some positive forcings to explain this extra warming. To the extent that human smoke emissions (and volcanoes) produce negative forcing we need to come up with even more.

The most obvious source for additional forcings is solar. But observations of solar activity show no change since 1950.

Another possibility is higher levels of water vapor in the atmpshere due to warmer temperatures. Water is a greenhouse gas and higher levels will produce additional warming. More water vapor will also likely mean more cloudiness, which exerts a cooling effect. The net effect of both will be some warming because to get increased cloudiness you have to have increased water vapor, which requires at least some increased temperature.

The effects of water vapor feedback can be estimated using complex computer models and are generally incorporated into the lambda parameter, raising its value from 0.3 to something higher (the consensus value is 0.5). But to be conservative we can account for the unknown amount of warming obtained from water vapor can simply saying that lambda will be greater than 0.3 (but we don't know how much) and so use the 0.33 degree warming by CO2 as a conservative estimate for Co2-induced warming (acknowledging that it could be higher).

So we have the following situation:

temperature rise = ~0.5 degree = at least 0.33 for human CO2 generation minus an unknown amount due to particulates plus unknown warming factors.

Since we know that there particulates and we know they exert a colling effect (we can see this happening when ever a big volanco erupts) there is a pretty big positive forcing needed to make the equation above balance unless the indirect effects of human CO2 are fairly large (i.e. lamda is significantly greater than 0.3).

It all comes down to this: either there is some unknown factor producing lots of warming, in which case we cannot assign a fraction of post-1950 warming to humans, or human CO2 generation is responsible for pretty much all of the post-1950 warming.

An anology might help. A man is found dead in a motel room. The autopsy reveals metastic cancer and the tox screen come up clean. Officer GW Skeptic believes that the man was murdered--poisoned in fact, since there are not visible marks on the body to suggest other means. The autopsy doctor points to the clean tox screen and Officer Skeptic counters that this screen doesn't test for all poisons. So the doctor runs tests on all known poisons and cannot find any. GW Skeptic says that proves nothing, since it could be a poison the doctor doesn't know about or one that doesn't leave any traces.

He insists that the doctor should record the cause of death as undetermined--possibly poison. The doctor wants to put down cancer, but GW Skeptic says that it hasn't been proven that cancer was the cause of death. Not only that but where is the evidence that the cancer actually cause the death at this time? People can live for weeks or months with metastatic cancer. How can you know that it caused the death at this moment in time?

Originally Posted by The Rani

I think there is another possibility, which is that other factors produce both warming and cooling, and we are caught in the middle of something that we don't even begin to understand.

That's the other factors possibility.

Originally Posted by The Rani

So, at best, unless someone else comes up with "evidence" about other factors affecting climate that have been studied, measured, and quantified, it seems like we are taking an educated guess about how and why we have a recent global temperature increase.

It is based on circumstantial evidence, like my cancer example. Both CO2 and the cancer have the means (CO2 can produce the warming and the cancer can kill), and both have the opportunity (both are present). But there is no direct evidence for either, the man could have been poisoned by an undetectable poison, or some mysterious unknown factor could be producing the warming.

Since, as Justin pointed out so many times, the only "model" that we have to work with is one planet, we can't even do controlled studies to try and figure it out. Given all this, in scientific terms, I think I would have to abandon the term Global Warming Theory and downgrade it to Global Warming Hypothesis.

You have the same issue with all non-experimental theories, like evolution, the big bang, stellar evolutions etc. Just because a science cannot be conducted in a laboratory doesn't mean it is invalid.

My next questions had to do with how much temperature change we could expect, its effect on the planet, and what we could do about it.

I have already provided the information for you to figure this out for yourself.

All you have to do is (1) pick a future CO2 level, I have come up with the following handy equation CO2 = 380 + 80*(exp(0.025*(t-2005))-1) where t is the year. The forcing expression forcing = 5.5 ln(CO2/380) lets you calculate the additional forcing from future rises in CO2. You then multiply by lambda = 0.3 if you are a skeptic and lambda = 0.5 if you are not.

But if all we're working with is CO2, I think we are fooling ourselves to think that we can figure any of that out.

Why? This doesn't make any sense.

Originally Posted by The Rani

Does this actually sound so awful? Yeah, we will have a lot of species rearrangements, but I think that predicting the end of humanity is a stretch.

It depends on how the rock bounces as it rolls down the hill. Species "rearrangements" could easily become a mass extinction event if species adapted to a particular environment can't re-adapt (or relocate) quickly enough. The thing about a mass extinction event is that it starts with one particular factor, and then balloons from there as one extinction causes the extinction of other species' dependent on the first die-off, and so on and so on. It could be the end of humanity if the biosphere unravels enough that some combination of species we're dependent on goes.

Short of that extreme, it's likely to involve severe economic hardships, especially since it gets combined with peak oil, overpopulation, water shortages, the top-heavy unsustainable configuration of our economy, and all the other stupid things we're doing. "End of humanity" is a worst-case scenario but it's bad news any way you slice it.

Originally Posted by The Rani

I don't know where the handy equation comes from, but it completely ignores factors other than CO2, so I wouldn't use it as a reliable indicator of temperature change that we can expect in the future. But looking around, I found this:

http://www.ncdc.noaa.gov/oa/climate/...l#INTROquation

"According to the range of possible forcing scenarios, and taking into account uncertainty in climate model performance, the IPCC projects a global temperature increase of anywhere from 1.4 - 5.8°C from 1990-2100.

The model is my own. I like to use my own models because then I know the assumptions built into it. The model I presented predicts 2-3.3 degrees of warming, which agrees just fine with the range the IPCC gives.

However, this global average will integrate widely varying regional responses, such as the likelihood that land areas will warm much faster than ocean temperatures, particularly those land areas in northern high latitudes (and mostly in the cold season)."

Does this actually sound so awful? Yeah, we will have a lot of species rearrangements, but I think that predicting the end of humanity is a stretch.

When did I say anything about the end of humanity? In fact I explicitly said that I believe that if we do nothing about global warming, the effect on me will be small and easily tolerated. It won't rock my world. Since you live in Chicago, are about my age and have no kids you have little to worry about. Sure unserious people preach GW doom and gloom. Unserious people also preach that we are gong to see a war of civilization, that the Dow is going below 4000 and that the dollar is going to become worthless. I don't pay attention to any of them.

That website also talks about other factors that can cause climate change, like the Earth's orbit, the Artic Oscillation (whatever the hell that is,) and points out the inconsistent evidence that although Arctic ice has decreased, Antarctic ice has not.

Orbital effects do affect climate, but not on the relevant time scale. Increasing Antarctic ice is expected from global warming. A warming Antarctic will still be below freezing. Warmer means more moisture in the air, more moisture means more snow and so the thickness of the ice sheet in the interior of Antarctica should be increasing. Also, this should be happening in the interior of Greenland to, but I don't know if it is. It doesn't happen at the North Pole because it,s not on land, and so it can get warm enough for melting in the summer.

Also mentions the unknown factors of human growth and development. So, unless you guys are claiming that this website is run by the Bushites and therefore heretical, there are TONS of other factors involved besides CO2, and TONS of unknowns.

This affects the amount of CO2 that will be added. I said pick a value of CO2. The projection I gave assumes we just keep on emitting CO2 at the same rising trend that we have been doing--business as usual. I doubt that is what is really going to happen, but it is what skeptics would recommend that we do.

Originally Posted by The Rani

My next questions had to do with how much temperature change we could expect, its effect on the planet, and what we could do about it. But if all we're working with is CO2, I think we are fooling ourselves to think that we can figure any of that out.

The problem is that the models we have are limited to linearity. We simply don't have enough of a handle on the actual dynamics of the system to do more than make that broad-brush assumption.

In fact all we can say on that matter is that the system appears to behave in a linear manner over the very small range for which we can correlate. As for 'evidence' that the model is most certainly not linear, I would point to the 'tipping points' that Bob alluded to some days ago -- that is, the points in the system where a radical change occurs due to a minor input change pushing some sort of major shift in the overall dynamic. Such behavior is not only characteristic of nonlinear systems, but cannot occur in linear ones. Of course, there is the other point that in natural processes almost nothing behaves in a linear fashion.

How far beyond where we have already been does the assumption of quasi-linearity hold? No one can say; null set; insufficient data.

And then, even given the fact that the system can be made to appear linear over a certain limited range, the fact is that nonlinear systems are not the sum of their parts.

As for testing the model more rigorously, It comes to me that, frankly, if AGW models are any good, we should see them work for the climate of other planets in our system. I've seen what appears to be good chunks of data for Venus, Mars, and Jupiter; if the linearity-assumption is actually broadly valid, a quasi-static run-through of the models using a dataset with wholly different parameters from Earth should at least come close to tracking reality. Has anyone tried that?

Originally Posted by The Rani

Let's take this question first ... what scientific evidence shows us how much global warming is caused by human factors, and how much is caused by others?

Let's start with the basic temperature history, then. I'll start with the longer term charts, and work those that go into finer detail over a shorter time frame. Various 'fundamental factors' show up on different scales. As you identify which 'squiggly lines' correspond to which fundamental factor, one can start to judge the time frame and scale of each effect.



The longest chart goes back 542,000,000 years. The dominant pattern on this time scale is the spiral arms. Stars in a spiral galaxy tend to clump together into concentrated and sparse areas. Cosmic rays, caused primarily by various flavors of star, are more intense where there are more stars. Cosmic rays effect cloud formation. Clouds bounce sunlight back into space, making the planet cooler.

Humans have not been around long enough to personally observe and record local star density and cosmic ray flux. One can tell how many cosmic rays hit various flavors of asteroids when they were hit. One can observe spiral arms in other galaxies. One can do experiments on how cosmic rays effect cloud formation in the laboratory. Satellites have been observing clouds no for several 11 year sunspot cycles. Thus, we have been able to observe cloud cover change with cosmic ray intensity, though the variations are from local effects not galactic ones. The astronomers have theories and equations showing how rapidly stars and galactic arms circle the galaxy, and the 135,000,000 years plus or minus 25,000,000 observed in the historical climate record are compatible with the astronomer's equations.

Not all of the major bumps in the first chart may be galactic arms. At this time scale, continents move. Mountains can alter prevailing wind patterns. A continent might position itself over a pole, allowing glaciers to form. There are discussions on what bump in the curve comes from what source. Still, the basic fundamental here is galactic arms, with very slow swings in temperature on the order of 20 degrees C in 135,000,000 years.



The second chart's shorter time scale exposes different effects. On notable one is Antarctic glaciation. If the south freezes over, one can expect a fairly abrupt 3 or 4 degree jump. The theory is that the whiter the planet, the more sunlight gets reflected back to space.

One can also note that slow changes of temperature do not cause extinction events. Abrupt changes are the problem. The labels on the bottom of the chart indicate periods where different types of life thrived. Such periods end with extinction events. Note a tendency for the extinction events to line up with abrupt climate changes.

The PETM (Paleocene-Eocene Thermal Maximum) may be the clearest pure greenhouse event. Temperatures at that time were slowly going up due to the galactic arm effect. The best working theory is that ice like clathrates in the ocean melted releasing methane, a potent greenhouse gas which in turn decomposes into CO2, which is another. Thus, the PETM shows an instance where a sudden and measurable release of greenhouse gas resulted in an abrupt change in temperature.

The PETM caused a change of 'only' 2 degrees C, but the speed of the change was significant. Give life forms time to evolve, and you don't get an extinction. The slower moving forces are survivable. It's not so much the amount of change but the speed of change.

To the right of the chart, we get into the recent ice ages, which are seen more clearly on the 5,000,000 year chart.



The Ice Ages involve two primary mechanisms, orbital variations, and glaciation. The Earths orbit changes in many ways. The angle of the axis shifts. Saturn and Jupiter tug at its orbit, shifting it from circular to elliptical and back. There are many such shifts which occur in regular predictable cycles. See Wiki's Milankovitch Cycles page for more details. At any rate, these various orbital shifts working at different rates generally measured in tens of thousands of years can effect how much heat is retained by the sun.

These shifts in orbit occur always. The result is not always as dramatic as it has been over the last five million years. Recent ice ages had temperature swings in the order of seven degrees. If one looks back to earlier on the 5 million year chart, the temperature swing was much smaller.

The difference is in glaciation. When temperatures were a bit warmer, the fairly small changes induced by orbital shifts were not enough to cause glaciers to form. As continents shifted and galactic arms progressed, the base temperature drifted low enough that a small additional change would cause glaciers to form. Glaciers reflected light into space, resulting in an additional cooling effect. As the Milankovitch orbital shifts reversed, melting the glaciers, the trend reversed.



At this point I am starting to get post fatigue, and have hit the 4 images per post limit on the board. I'm tired of writing. I'm sure others are tired of reading. I'll briefly mention that volcanoes can throw dust in the air, causing clouds to form, reflecting sunlight, thus cooling. I'll mention that the sun fluctuates, effecting cosmic rays, and thus clouds, much like the galactic arms do except on a much faster time scale. If necessary, I'll show more squiggly line showing these factors do exist, and the net effects of what happens when they do come into play. I also suspect I've missed a fundamental mechanism or two, or three, but enough for one post.

One of the basic difficulties is that CO2 levels do not stay stable. As the oceans heat, the oceans hold less CO2, and release it into the atmosphere. As the climate cools, the oceans can absorb more gas back in. The result is a positive feed back effect. As an orbital shift can cause a glacier to form, so too the orbital shift and the glacier together cool the ocean, causing it to absorb CO2. With less greenhouse gas in the atmosphere, this causes additional cooling. This leads to more glaciers, and less CO2.

How does one judge how much cooling in a given era is caused by the orbital shifts, how much by the glaciers, and how much by the CO2? That's where it gets more complicated than a layman can easily grab a hold of. If I can get an acknowledgment that there is evidence for some of the easier to observe and understand fundamental mechanisms, I'll try to move on the the CO2, which rarely acts alone. (The PETM is one of the more visible tipping point examples of greenhouse being suddenly introduce in a way that its effects are easily visible in the historical data.)

One other note on tipping points, on feedback. Feedback can fight the direction of change, or accelerate it. One negative feedback mechanism, more heat, results in more storms, more clouds, more light reflected back into space, is a stabilizing influence. More heat in that mechanism leads to a cooling effect. The opposite is a positive feedback mechanism. More heat, the ocean can hold less CO2, CO2 is released into the atmosphere, starts acting as a greenhouse gas, more warming. Both theories are easy to understand. The basic measurements can be taken in the wild, and replicated in miniature in the lab. Both happen.

But if you don't have measurements of things like percentage cloud cover and CO2 gas concentration, it is hard to estimate how much of one mechanism is occurring, and how much the other. If one knows when the glaciers or the Antarctic froze and melted, and can look at the temperature record to see changes at these times, one can attributed triggering shifts to various causes. As gas fluctuations are more continuous and regular than galactic arms and orbital variations, it is harder to attribute this much effect to that cause.

But the problem with positive tipping points is that they are kind of like driving off a cliff. Once the tundra starts releasing methane, you get a sudden (by climate standards) spike, such as the PETM or the Antarctic glaciating. Justin seems to be pushing an argument by complexity position that we don't understand enough about the system. Perhaps some non-linear factor we don't understand will save us. The problem is that we are approaching known tipping points which will move us in the wrong direction. To placate me entirely, Justin not only has to optimistically assume the existence of forces which he cannot even name that could drive the system cold, he has to debunk fundamental forces which we can measure and can see already in action.

We are not all that far from the breakpoint in the historical curves where the Antarctic starts melting. Gain five degrees C. Do not pass Go. Do not collect $500. Some here are content say, sure, we'll hold it to a small extinction event. We don't need an all out effort. I look at the way the temperature jumps when Antarctica starts to melt or freeze, and am dubious. If we are not very careful about managing the small extinction event, we could get a big one.

Next time, I've got historical records of CO2 gas concentrations, assuming any acknowledgment by the 'skeptics' that evidence does exist for many of the fundamental mechanisms. Yes, I haven't dived into CO2 hard yet. Justin and The Rani are correct that there are many forces in play. They are not correct in assuming they cannot be understood. I thought I'd introduce the known forces that can be seen fairly clearly first.

Originally Posted by Justin '77

As for testing the model more rigorously, It comes to me that, frankly, if AGW models are any good, we should see them work for the climate of other planets in our system. I've seen what appears to be good chunks of data for Venus, Mars, and Jupiter; if the linearity-assumption is actually broadly valid, a quasi-static run-through of the models using a dataset with wholly different parameters from Earth should at least come close to tracking reality. Has anyone tried that?

Welcome to the homepage of the Mars General Circulation Modeling (MGCM) Group in the Planetary Systems Branch of the Space Science Division at NASA Ames Research Center . The various links above tell you who we are and what we do. Also provided is a compilation of interesting background information about Mars.

Top image information: The image above was created using a variety of images. On the left, is a computer model of Mars, developed by the MGCM Group using Mars Global Surveyor (MGS) and Mars Orbiter Laser Altimeter (MOLA) topography, which shows the surface pressure anomaly.

High (anti-cyclonic) pressure anomaly is red and low (cyclonic) pressure anomaly is black/purple. The aircraft to the right of the model is the MGS. The landscape on the right is an image (MOC2-144) taken from the Mars Orbiter Camera which shows clouds over Tharsis and Valles Marineris.

I think I have to put 10 characters here. Not sure what there really is to say...

Um. Bob.

I said a good proof attempt would be using AGW models (that is, climate) to run on other systems for which we have data. The website you linked to, however:

The primary goals of our research are to understand the nature of the general circulation of the atmosphere of Mars, how that circulation is driven and how it affects martian long term climate. These studies in turn help us to understand the nature of the martian water, dust and atmospheric pressure cycles.Results of our computer modeling studies also support numerous Mars missions either underway or under study. To accomplish this, we use a number of computer models. The simplest of these represents the atmosphere by a vertical column stretching up from the surface to some specified height. This model simulates effects such as atmospheric heating by gases and ground-air heat transfer.
The most complex is a 3 dimensional (height, latitude, longitude) model, which represents the processes in the simpler model, as well as large-scale atmospheric motions. The latter is called a GCM (General Circulation Model), and is similar in a lot of ways to the computer models that are used for weather prediction on the Earth.


...


The NASA Ames Mars General Circulation Modeling (MGCM) Group contributes to mission designs and procedures by providing forecasts of the behavior of the Martian atmosphere. Examples of these are wind speeds during the landing of a spacecraft (such as Mars Pathfinder and the Mars Volatiles and Climate Surveyor) or atmospheric density variations during an aerobraking maneuver (such as the one that Mars Global Surveyor is undergoing).

In case you are wondering, this is the Mars General Circulation Model. That is, a weather model. And as has been pointed out [by you], weather and climate are two different things...


(Did you even read your link? Were you not expecting anyone to click through?)

Originally Posted by The Rani

Yeah, but there are a lot of variables in "human activity" besides CO2. I suppose you could say "everything else being the same and CO2 increasing ..." but I don't think that's a realistic set of circumstances. It's possible that we do (or will do) other stuff to affect climate that we don't even know about yet. Every action has effects that can't be predicted, which I think is part of the "linear versus chaotic" thing. Your model might work in a linear system, but in the real world it could mean absolutely nothing.

The same can be said about the example of the dead man with cancer. He could conceivably have been murdered, but there is no evidence for that. So the circumstantial evidence of the cancer rules and the ME will call the death natural.

All these appeals to "lot's of variables" and "linear vs. chaotic" and actions that have effects that can't be predicted are hand waving. There are no specifics. What activities or other variables will overwhelm the CO2 effect?

These sorts of objections are true of everything all the time. If we took them seriously we would all still be in caves.

Is there any evidence that the climate behaves chaotically other than wishful thinking? Sure weather is chaotic. But chaos doesn't mean we can say nothing about the weather of the future. I can be quite sure that the high on July 4 in Kalamzoo won't be below 40 F, nor will it be above 120 F. How can I do that? Because weather is constrained by climate. Climate is the "attractor" which restricts chaotic weather from wandering all over the phase space.

The temperature produced by chaotic weather can be defined as climate + noise. If one averages daily temperature values obtained from N=2500 locations all over the globe you can produce a value for daily global temperature. The size of the noise falls by the square root of N, so if weather causes a plus or minus 40 F variation about the climate, the noise falls to plus or minus 0.8 degrees F. And if we average daily global temperatures over a whole year the noise will fall to 0.042 F (0.023 C) for global annual temperatures.

So weather chaos means that the modern annual global temepratures of the kind seen plotted on the internet estimate the true value of the climate to about 2 hundreths of a degree. Since the changes in these averages are much larger we can be sure that chaos isn't affecting our ability to track climate in the modern data. Chaos does affect our ability to track historical climate because there are fewer locations providing data.

CNet news reviews prospects for solar energy generation. Right now, some are saying the magic price for competing with gas generated power is 10 cents per kilowatt hour. Solar is starting to get close, but isn't quite in a position to be competitive yet without subsidies.

The article is interesting in that it ends on a nice First Turning note. What sort of infrastructure might be built?

For discussion purposes..

Utilities will also likely work hard to lower the costs of solar thermal in the coming decades, Morse added. Utilities are under mandates to increase their renewable energy sources. Citizen groups often complain about wind turbines and the wind doesn't blow at a constant, predictable rate. Several companies are intent on tapping heat from under the surface of the earth to generate power. Geothermal power, however, works best only in certain locations.

"There is an enough flat, unproductive land in the U.S. to power the U.S.," Morse said. "We just don't have the wires to get there. Eisenhower built the national highway system. Some president will build the national grid."

CNet seems to be running a series on green technologies. Here is one on a topic Mike has mentioned, seeding the ocean with iron to promote algae growth.

Later this month, a crew from a company called Planktos will head for waters near the Galapagos Islands to see whether lowly plankton have a role in mitigating climate change.

The idea behind the venture is to create plankton "blooms," or large-scale growth, by seeding the ocean with iron, which stimulates plankton growth. As the plankton grows, it consumes carbon dioxide, a greenhouse gas, and removes it from the atmosphere.

And another CNet algae article, this one about algae farms located next to coal power plants, converting CO2 into animal feed.

First off, algae grows rapidly and grows constantly, which means that algae ponds can produce more oil per hectare in a year than traditional plant crops, said GreenFuel CFO Guillermo Espiga.

A hectare pond filled with algae can produce 15,000 to 80,000 liters of vegetable oil a year. Only about 6,000 liters of palm oil can be squeezed out of a hectare a year. Corn is only good for 120 hectares of oil a year, Espiga said.

Algae can also be converted into a variety of materials, insulating producers from changes in commodity prices to some degree. It can be turned into alcohol for ethanol, biomass that can be burned in a furnace, or animal feed (which can also be sold under the Soylent Green brand name in grocery stores). A single hectare can generate 8,000 gallons of oil, 2,400 gallons of ethanol a year and 2.6 tons of glycerin, a material bought by the cosmetics industry, he said.

But there's more. GreenFuel plans to produce algae in ponds next to coal-fired power plants. The carbon dioxide from the plants is captured and provides the food for growing the algae. At a 100 megawatt coal-burning power plant, 100 acres of algae ponds, optimized with species that grow well in that particular environment, will consume 90 percent of the CO2 from the plant.

Thus, power plants that deploy the technology will generate revenue from carbon credits as well as make money from selling feedstocks. Espiga estimates that there are 1,750 power plants in the U.S. that sit next to spare real estate that could accommodate some of GreenFuel's algae ponds. The standard size of the algae facilities will be around 250 acres, he said.

It is nice seeing options being considered which don't seem too out of line economically. It is also decent to see multiple options being considered.

Originally Posted by Justin '77

The problem is that the models we have are limited to linearity.

This is problem for Justin, not with the science.

In fact all we can say on that matter is that the system appears to behave in a linear manner over the very small range for which we can correlate.

The system behaves linearly for the conditions of interest. There is no evidence of nonlinearity.

As for 'evidence' that the model is most certainly not linear, I would point to the 'tipping points' that Bob alluded to some days ago -- that is, the points in the system where a radical change occurs due to a minor input change pushing some sort of major shift in the overall dynamic.

This is nonsense. Tipping point simply refers to path dependence of temperature changes. That history matters. The CO2 level needed to re-freeze the ice caps is going to be much lower than the one that prevents the caps from melting in the first place.

Another tipping point is the release of trapped methane. The same level of CO2 will give a higher temperature in a world in which methane was released in the past than in one in which it was not. Once again, an effect of history--not non-linearity.

All that melting ice caps or release of methane do is add a new forcing to the linear model.

There is a difference between uncertainty due to chaos (which cannot be addressed) and uncertainty due to lack of knowledge (which can be addressed by better knowledge). Justin is conflating the two.

Originally Posted by Bob Butler 54

Let's start with the basic temperature history, then. I'll start with the longer term charts, and work those that go into finer detail over a shorter time frame. Various 'fundamental factors' show up on different scales. As you identify which 'squiggly lines' correspond to which fundamental factor, one can start to judge the time frame and scale of each effect.



The longest chart goes back 542,000,000 years. The dominant pattern on this time scale is the spiral arms. Stars in a spiral galaxy tend to clump together into concentrated and sparse areas. Cosmic rays, caused primarily by various flavors of star, are more intense where there are more stars. Cosmic rays effect cloud formation. Clouds bounce sunlight back into space, making the planet cooler.

Humans have not been around long enough to personally observe and record local star density and cosmic ray flux. One can tell how many cosmic rays hit various flavors of asteroids when they were hit. One can observe spiral arms in other galaxies. One can do experiments on how cosmic rays effect cloud formation in the laboratory. Satellites have been observing clouds no for several 11 year sunspot cycles. Thus, we have been able to observe cloud cover change with cosmic ray intensity, though the variations are from local effects not galactic ones. The astronomers have theories and equations showing how rapidly stars and galactic arms circle the galaxy, and the 135,000,000 years plus or minus 25,000,000 observed in the historical climate record are compatible with the astronomer's equations.

Not all of the major bumps in the first chart may be galactic arms. At this time scale, continents move. Mountains can alter prevailing wind patterns. A continent might position itself over a pole, allowing glaciers to form. There are discussions on what bump in the curve comes from what source. Still, the basic fundamental here is galactic arms, with very slow swings in temperature on the order of 20 degrees C in 135,000,000 years.

Bob, it's my understanding that the long-term changes over geologic time are almost entirely the result of tectonic activity. Orogenic (mountain chain formation) events remove CO2 from the atmosphere, causing cooling. Volcanic activity releases CO2 into the atmosphere, causing warming. continents at or near the poles results in ice sheet formation, resulting in cooling fom albedo and and cooling and drying from the chilling of the deep oceans (the abrupt End-Eocene cooling is almost entirely from the effects of the glaciation of Antarctica, for example).

The Ordovician Ice Age is the result, IIRC of the Taconic-Caledonian Orogeny (which formed the northern Appalachians, the mountains of Norway and the Scottish Highlands)

The Carboniferous-Permian Ice Age was the result of the orogenies resulting from the formation of Pangaea.

The Mid-Mesozoic cool period was the result of the orogenies associated with the consolidation of Asia.

The modern Ice House world is the result of the Alpine, Himalayan, and Andean orogenies.

Originally Posted by Justin '77

In case you are wondering, this is the Mars General Circulation Model. That is, a weather model. And as has been pointed out [by you], weather and climate are two different things...

Weather models run at a higher resolution and attempt to capture small scale chaotic effects. Climate models are concerned with broader averages and longer time frames. The distinction between what is a long term as opposed to short term model seems to vary considerably depending on how much data one has on a planet. I stumbled on one article mentioning the Mars General Circulation Model, which implies the same model is being used for both long and short term effects.

A couple of basic issues first : the Martian year is about 2 Earth years (687 days). Currently it is late winter in Mars's northern hemisphere, so late summer in the southern hemisphere. Martian eccentricity is about 0.1 - over 5 times larger than Earth's, so the insolation (INcoming SOLar radiATION) variation over the orbit is substantial, and contributes significantly more to seasonality than on the Earth, although Mars's obliquity (the angle of its spin axis to the orbital plane) still dominates the seasons. The alignment of obliquity and eccentricity due to precession is a much stronger effect than for the Earth, leading to "great" summers and winters on time scales of tens of thousands of years (the precessional period is 170,000 years). Since Mars has no oceans and a thin atmosphere, the thermal inertia is low, and Martian climate is easily perturbed by external influences, including solar variations. However, solar irradiance is now well measured by satellite and has been declining slightly over the last few years as it moves towards a solar minimum.

So what is causing Martian climate change now? Mars has a relatively well studied climate, going back to measurements made by Viking, and continued with the current series of orbiters, such as the Mars Global Surveyor. Complementing the measurements, NASA has a Mars General Circulation Model (GCM) based at NASA Ames. (NB. There is a good "general reader" review of modeling the Martian atmosphere by Stephen R Lewis in Astronomy and Geophysics, volume 44 issue 4. pages 6-14.)

In mentioning solar variations and different axial tilts and orbit shapes, they are including lessons learned from Earth's climate studies. Those are two of the 'fundamentals' I've been trying to bring into the conversation on Earth's climate, clearly included in the Mars simulation. Still, in the short term, the Milankovitch equivalents would not have changed since the Viking probes landed. We don't have a long term history of climate on Mars. Tweaking the Mars GCM to run at coarser resolutions to cover centuries or millennia of change might be done, but without hard data to compare it against, I'm not sure what one might expect to learn that could be confirmed.

One 'fundamental' on Mars which is far less a factor on Earth is Mars' lack of a magnetic field. Many suspect that Mars is no longer volcanic. As there is no longer a flow of hot metal and electric charge in the core of the planet, there is no magnetic field being produced. Thus, there are no Van Allan belts, and there is much less protection from solar wind. Thus, the atmosphere of Mars is slowly being blown into space. Mars is losing air. This may be why there is evidence of water erosion on the surface, but no water. There may once have been enough air and enough water for rain, streams, lakes and erosion, but then the planetary core locked up, the air and the water vapor suspended in the air started to get blown away.

Until we know a lot more about when Mars lost its magnetic field and how rapid the resultant loss of atmosphere has proceeded, long term climate studies of Mars remain wide open to conjecture.

Still, they are modeling other planets, and the models are useful in explaining what is going on. The Earth models are much more specialized than the Mars model. We have a lot more data about Earth, not to mention a bigger budget. On Earth we need screwdriver, hammer and set of allen wrenches to try to get the job done. Mars is getting a Swiss Army Knife. Given the much thinner atmosphere, much less going on, the Swiss Army Knife might be enough to get the job done.

Thus, power plants that deploy the technology will generate revenue from carbon credits as well as make money from selling feedstocks.

Since many of the products produced from the algae are to be burned, releasing the CO2 produced by burning the coal, I don't see where the carbon credits are going to come from. Why not sequester the CO2 from the plant and still make the algae product? In fact, why not use the algae instead of the coal? Zero emissions, carbon credits plus electricity for sale--with zero fuel costs. And with algae you can minimize sulfur content.

With CO2 sequestration one could achieve net removal of CO2 from the atmosphere (which may be necessary--especially if one of those "tipping points" is activated).

Originally Posted by Odin

Bob, it's my understanding that the long-term changes over geologic time are almost entirely the result of tectonic activity. Orogenic (mountain chain formation) events remove CO2 from the atmosphere, causing cooling. Volcanic activity releases CO2 into the atmosphere, causing warming. continents at or near the poles results in ice sheet formation, resulting in cooling fom albedo and and cooling and drying from the chilling of the deep oceans (the abrupt End-Eocene cooling is almost entirely from the effects of the glaciation of Antarctica, for example).

The Ordovician Ice Age is the result, IIRC of the Taconic-Caledonian Orogeny (which formed the northern Appalachians, the mountains of Norway and the Scottish Highlands)

The Carboniferous-Permian Ice Age was the result of the orogenies resulting from the formation of Pangaea.

The Mid-Mesozoic cool period was the result of the orogenies associated with the consolidation of Asia.

The modern Ice House world is the result of the Alpine, Himalayan, and Andean orogenies.

That is the older theory. I don't in the least doubt that continental shifts and mountain ranges are a factor. It was actually Justin's links to various articles on stellar topography and cosmic rays that brought me up to date on the galactic perspective. To the extent that some of what Justin is saying does have some supporters in main line science, I'm trying to give Justin his due.

But I'll admit I'm weak on where the contenents were a long time ago. Continental drift does count as a fundamental in my opinion. If you'd care to link to a few pages which emphasize that aspect of climate change, be my guest.

But in the long term, nothing that is going to show up clearly on the 500,000,000 year chart is going to be a major factor in looking for that .7 degrees C anomaly in a century. In terms of explaining global warming, neither galactic arms or continental drift seem likely to be major players.

Originally Posted by The Rani

As for the chaos issue, Justin is right that almost nothing in nature behaves in a linear fashion.

There's a lot in nature that doesn't, more than most people realize, but I wouldn't agree that "almost nothing" does. There are a lot of natural processes that do. Here are some examples:

Rate of acceleration of falling objects
Path of orbit of satellites (natural or artificial)
Boiling point of water
Rate of decay of radioactive elements
Rate of reproduction of bacteria
Molecular weight of products of chemical reactions
Trajectory of a projectile shot from a gun
Coefficients of friction of various substances

There are lots of others, and sometimes a process that is chaotic or indeterminate can feed into a larger process that suppresses the chaos and becomes linear and strictly predictable. A good example is the temperature and pressure of a gas within a container. The motion of the individual gas molecules is chaotic, but the aggregate pressure and temperature of the gas molecules is linear, because under normal probabilities all the stochastic variables cancel out.

Apparently climate is like that. It's aggregate, average weather, just as gas pressure is aggregate, average motion of gas molecules. Weather is chaotic, but its stochastic variables cancel out over time, leaving something more predictable. The specific high temperature on a particular day is not predictable more than two or three days away, but the average temperature of a whole season is.

Originally Posted by Brian Rush

There's a lot in nature that doesn't, more than most people realize, but I wouldn't agree that "almost nothing" does. There are a lot of natural processes that do. Here are some examples:

Rate of acceleration of falling objects
Path of orbit of satellites (natural or artificial)
Boiling point of water
Rate of decay of radioactive elements
Rate of reproduction of bacteria
Molecular weight of products of chemical reactions
Trajectory of a projectile shot from a gun
Coefficients of friction of various substances

You could even add in some multivariate examples, like the behavior of a mass-spring.

But, what those all have in common, aside from their being at most three-variate systems, is that the forcing parameters do not feed back onto each other. That is, regardless the mass, the stiffness of the spring simply is what it is; and regardless the velocity of its movement (assuming non-relativistic speeds; I'm not sure how it would look then) the mass is what it is.

With climate, however, there are several forcing variables which do feed back onto themselves and each other. One simple example would be the fact that the CO2 forcing, upon which in part the climate depends, is itself affected by the climate in the form of (two off the top of my head):

- Temperature-based changes in the saturation pressure of CO2 in the ocean-sinks
- Differing rates of CO2 sequestration in biomass due to the ground-level solar flux (more sunlight, all other things equal, means more biomass; conversely more cloud cover, all other things being equal, means less biomass)

Feedback = nonlinear. Mathematics is really simple as that.

...sometimes a process that is chaotic or indeterminate can feed into a larger process that suppresses the chaos and becomes linear and strictly predictable.

The statement you make is flatly incorrect. Chaotic processes (even a single one in isolation) can behave as if they were linear over discrete ranges. But being chaotic, nothing in their apparently-linear behavior interval will give any indication of its exact bounds, or of what it will do as son as those bounds are crossed.

A good example is the temperature and pressure of a gas within a container.

In fact, this is an excellent example. Gas in a container behaves in a quasi-linear fashion, under certain conditions. Those would consist (at a minimum) of:

Upper and lower bounds on the pressure of the gas in the container.
Upper and lower bounds on the temperature of the gas.
At least a lower limit on the volume of the container.
At least a lower limit on the quantity of gas molecules in question.

That is, for all the variables. And it is not obvious from the Ideal Gas Law (PV=nRT, to which I presume you were referring) exactly what those bounds are, or what happens outside them.

The quasi-linearity of the climate models is the same. Without some sort of empirical demonstration of where the bounds of quasi-linearity are, we cannot simply assume that any behavior outside the bounds of what we have already observed and correlated will continue to follow the same quasi-linear path.

Originally Posted by Justin '77

But, what those all have in common, aside from their being at most three-variate systems, is that the forcing parameters do not feed back onto each other.

Not true with respect to the reproduction of bacteria. In any case, forcing parameter feedback does not automatically lead to chaos. Such feedbacks can take forms that are not infinitely sensitive to initial conditions. I'll give you a simple mathematical example.

Variable A varies as B. Variable A varies as the square root of C. C varies inversely as 2B. B varies as C. B increases linearly with an initial value of 1, gaining 1 unit per day.

Run this for 100 days with initial conditions A=100 and C=50. Then run it for another 100 days with initial conditions A=99 and C=51. Make other variations as you see fit. The system has forcing parameter feedback in the relations between variables B and C, but it is not chaotic.

The statement you make is flatly incorrect. Chaotic processes (even a single one in isolation) can behave as if they were linear over discrete ranges. But being chaotic, nothing in their apparently-linear behavior interval will give any indication of its exact bounds, or of what it will do as son as those bounds are crossed.

The statement I made was not incorrect, you misunderstood it. I said that chaotic processes can feed into larger processes that are not chaotic -- not that the chaotic processes themselves can become non-chaotic. An example, which you acknowledged as excellent, is the pressure of a gas within a container. The motion of the molecules of gas (which is chaotic) feed into the aggregate force of all molecular gas motion, which determines the pressure as a function of temperature and density, and that is non-chaotic. The motion of the individual molecules does remain chaotic, however.

In the same way, chaotic weather feeds into the aggregates that we refer to as climate. Thus we are able to predict ranges of temperature, precipitation, wind speed and direction, and so on for a given location and time of year with far greater accuracy than we can predict exact precipitation for a location on a particular day. (Unless that day is today or tomorrow.)

All processes are indeterminate at root. That is, all processes are aggregates of molecular motion and quantum events, and those events are indeterminate. However, just as we can predict the aggregate outcomes of a million die rolls reliably, even though we cannot predict the outcome of a single die roll at all, so there are many processes in nature in which the variables involved in these indeterminate events cancel out and the aggregate outcome may be treated as determinate. There are others in which the variability is preserved. Actually, the roll of a die is one of those. But just as the motion of a billiard-ball, although the outcome of many indeterminate events, can itself be treated as determinate, so can the aggregate of a million die rolls, also the outcome of many indeterminate events (although larger-scale ones) be treated as determinate.

And so, apparently, can the climate.