Bob Park and Global Warming

[Brian the Snail]

Oh, not John Daly. I did all that before with someone called Titanpoint. Just look at it as if you didn't like it; would you find it convincing? I look at everything that way.

Oh, didn't you know? Diamond is Titanpoint.

 

[Diamond]

Oh, didn't you know? Diamond is Titanpoint.

Oh didn't you know? I am neither.

In any case who I am has no bearing upon facts, upon evidence, upon logic, upon science.

It's as obvious as Newton's Laws of Motion or the fact that the sky is blue.

 

[Brian the Snail]

In any case who I am has no bearing upon facts, upon evidence, upon logic, upon science.

Yes, I know. Just pointing out something, that's all. Just call it a Public Service Announcement, if you like.

It's as obvious as Newton's Laws of Motion or the fact that the sky is blue.

What? The fact that you are Titanpoint. Yes, I agree.

 

[Diamond]

Now Brian, having had a few spins on the Magic Roundabout, care to have a go at the Idsos on the issue of carbon dioxide and warming, because we're all fascinated by what you can say on the subject.

Oh and does Capel Dodger's claim that proxy evidence, apart from the carbon dioxide proxy, does not present evidence for climate change in the past 1000 years to compare with the European historical record?

Or are the refutations as obvious as Newton's Laws of Motion or the fact that the sky is blue?

 

[mummymonkey]

Has anyone read this chaps book? This is from his web page.

In short, the reported warming is inconsistent with warming due to greenhouse gases in its temporal, vertical, and geographical distribution. The reported warming is consistent with problems in the surface network.

Seems to be firmly in the skeptics camp.

 

[Brian the Snail]

Now Brian, having had a few spins on the Magic Roundabout, care to have a go at the Idsos on the issue of carbon dioxide and warming, because we're all fascinated by what you can say on the subject.

Hope you enjoyed the ride.

Alas, you give me too much credit, since my thoughts on the matter are of no interest to anyone. However, I did find this very interesting (and seemingly balanced) article from J. D. Mahlman at the Geophysical Fluid Dynamics Laboratory. Particularly interesting is the section "Some Fundamental Aspects of Greenhouse Warming Science" where he says:

The earth is strongly heated every day by incoming radiation from the sun. This heating is offset by an equally strong infrared radiation leaving the planet. Interestingly, if Earth were without any atmosphere, and if its surface reflectivity did not change, global-mean surface temperature would be roughly 33°C colder than it is today. This large difference is due to the strong atmospheric absorption of infrared radiation leaving the earth's surface. The major atmospheric infrared absorbers are clouds, water vapor, and CO2. This strong infrared absorption (and strong reemission) effect is extremely robust: It is readily measured in the laboratory and is straightforwardly measured from earth-orbiting satellites. Simply put, adding CO2 to the atmosphere adds another "blanket" to the planet and, thus, directly changes the heat balance of the earth's atmosphere.

Individuals skeptical about the reality of global warming have correctly noted that, in terms of direct trapping of outgoing infrared radiation, water vapor is by far the dominant greenhouse gas on earth. Since water vapor dominates the current radiative balance, how can it be that CO2 is anything other than a minor contributor to earth's absorption of infrared radiation? Part of the answer comes from the well-known modeling result from infrared spectroscopy that net planetary radiative forcing changes roughly linearly in response to logarithmic changes in CO2 . Thus, a quadrupling of CO2 gives another roughly 1°C direct warming over the direct 1°C warming for a CO2 doubling, valid for the extreme assumption that water vapor mixing ratios and clouds do not change. Interestingly, this approximate relationship also holds for a large extended range as CO2 is decreased (see footnote 3).

It is thus hard to escape the conclusion that CO2 provides a measurable direct addition to the atmospheric trapping of infrared radiation leaving the surface of our planet.

(Emphasis mine). He then goes on to discuss problems with this simple picture due to the water vapor acting as a "feedback gas", which is of course where much of the controversy lies (and in which, I am undecided, BTW).

Does this answer your concerns?

Oh and does Capel Dodger's claim that proxy evidence, apart from the carbon dioxide proxy, does not present evidence for climate change in the past 1000 years to compare with the European historical record?

I don't remember commenting on this before, so I'm not sure why you want my opinions now. Perhaps you are mixing me up with someone else? In any case, I am following the debate with interest. Both yourself and kookbreaker raise interesting points, I feel. Though I did think that your accusations of racism against CapelDodger were unneccessary and unfounded.

 

[Diamond]

I don't remember commenting on this before, so I'm not sure why you want my opinions now. Perhaps you are mixing me up with someone else? In any case, I am following the debate with interest. Both yourself and kookbreaker raise interesting points, I feel. Though I did think that your accusations of racism against CapelDodger were unneccessary and unfounded.

What I found unfounded was Capel's dismissal of contrary evidence to his beliefs: that only the Europeans had a clear historical record of the Little Ice Age and that all modern proxy investigations were invalid because only the European historical record mattered.

Apart from the carbon dioxide proxy of course....

Now, having dealt with inept analogies on whether carbon dioxide behaves like a blanket, would you care to cite a single study which shows that carbon dioxide enrichment in fact does cause temperature rise. Refer to any proxy studies done in the climate record, because I can't find any. Notice that your scientific result refers to a modeling result, not actual data from the climate record that demonstrates this.

Also, if carbon dioxide is such a wonderful blanket of heat, why does the temperature of Mars vary by 200 degrees between day and night despite having a partial pressure of carbon dioxide more than ten times higher than on Earth and similar length of day?

 

[a_unique_person]

Yes, I know. Just pointing out something, that's all. Just call it a Public Service Announcement, if you like.



What? The fact that you are Titanpoint. Yes, I agree.

Titanpoint. Now it all makes sense.

 

[a_unique_person]

What I found unfounded was Capel's dismissal of contrary evidence to his beliefs: that only the Europeans had a clear historical record of the Little Ice Age and that all modern proxy investigations were invalid because only the European historical record mattered.

Apart from the carbon dioxide proxy of course....

Now, having dealt with inept analogies on whether carbon dioxide behaves like a blanket, would you care to cite a single study which shows that carbon dioxide enrichment in fact does cause temperature rise. Refer to any proxy studies done in the climate record, because I can't find any. Notice that your scientific result refers to a modeling result, not actual data from the climate record that demonstrates this.

Also, if carbon dioxide is such a wonderful blanket of heat, why does the temperature of Mars vary by 200 degrees between day and night despite having a partial pressure of carbon dioxide more than ten times higher than on Earth and similar length of day?

Talk about comparing apples and oranges. From what I understand, the basic reason would be that the atmosphere of Mars is much thinner than that on earth.

The term greenhouse gas simply refers to the simple fact that the general class of such gases react differently to solar radiation than the 'normal' atmosphere such that they retain more heat, much as a glasshouse does.

The modelling you refer to is checked against past temperatures to see how accurately it models the past, so that the reliability of the projections can be assessed.

For example, the recent weather events in Eurpope, extreme flooding followed by extreme heat, fit in with the model projections. These events in themselves are not conclusive proof, but they do indicate the models are accurate.

 

[pupdog]

I see no problem with a "spectator" like Diamond expressing an opinion, based on what he has read.

But today I read yet another report (Science, 2 or 3 weeks back) where increased altitude of the tropopause in the last few decades was attributed in large part to anthropogenic causes, specifically greenhouse gases.

From what I've read, it appears certain that warming has occurred--the question is, how much is due to "natural" causes and how much is due to human activity. And multiple studies, following multiple lines of reasoning, conclude that human influence is significant.

There are substantial uncertainties, and some mechanisms may not be precisely addressed in the modeling, so policy decisions will be politically based. what are the consequences of the various decisions?

 

[Diamond]

Talk about comparing apples and oranges. From what I understand, the basic reason would be that the atmosphere of Mars is much thinner than that on earth.

Not at all. The example of Mars is an excellent test of whether carbon dioxide is a meaningful greenhouse gas in the absense of confounding factors like water vapour.

The reality is, is that carbon dioxide is a very poor greenhouse gas, re-radiating large amounts of energy out of the atmosphere as well as keeping some heat in.

The partial pressure of carbon dioxide on Mars is more than ten times that of Earth. If there was a significant "greenhouse effect" due to carbon dioxide alone, that's where you'd see it.

Except you don't.

The term greenhouse gas simply refers to the simple fact that the general class of such gases react differently to solar radiation than the 'normal' atmosphere such that they retain more heat, much as a glasshouse does.

A glasshouse retains heat by suppressing convection with the outside. The earth's atmosphere convects mightily but 80% of the heat transport of the earth is via the oceans, not the atmosphere.

A lot of the problems of people trying to understand climate appear to be caused by poor metaphors like "the Greenhouse effect"

The modelling you refer to is checked against past temperatures to see how accurately it models the past, so that the reliability of the projections can be assessed.

In that case you would be able to point to those studies which show carbon dioxide rise causing temperature rise, wouldn't you?

For example, the recent weather events in Eurpope, extreme flooding followed by extreme heat, fit in with the model projections. These events in themselves are not conclusive proof, but they do indicate the models are accurate.

Its nice to know the models fit so well to Europe. On the other hand they did not predict the cold winter in between that affected most of the Northern Hemisphere, although someone was contacted in the middle of the winter and said that "the models predict that colder winters are also part of the global warming scenario". In any case the flooding last year was caused by storm tracks being further SOUTH than normal, which is why the "Global Warming" lobby went relatively quiet during that time.

If it wasn't Europe, it would be another part of the world, with drought, or flooding, or sleet. The possibilities are endless since there's always extreme weather happening somewhere in the world and with the aid of a a few television cameras and a satellite link or two, you could convince everybody every day that the climate was going to hell in a handbasket, even if such a thing was simply the result of better reporting, rather than any increase in weather events themselves.

Its difficult to know how to respond to claims like "they indicate the models are accurate" since the models themselves have large numbers of parameters which are not set by measurement or theory but by the programmers themselves. Since the programmers decide which is and which is not a valid run, it seems to me that the process is contaminated with human post hoc explanations. Its also impossible to deny that they do not make consistent predictions even with each other, since such discrepancies are pointed out regularly.

In my opinion "Global warming" is not a science (although it claims to be based on science) but a religious and political exercise. As such it makes no claims that can be falsified and no weather event, cold or hot, rain or shine, that is not predicted by the "Theory". The entire paradigm is self-reinforcing and self-perpetuating.

 

[Diamond]

I see no problem with a "spectator" like Diamond expressing an opinion, based on what he has read.

But today I read yet another report (Science, 2 or 3 weeks back) where increased altitude of the tropopause in the last few decades was attributed in large part to anthropogenic causes, specifically greenhouse gases.

The notorious John Daly writes his response at www.john-daly.com in the front page in the section called "Gone Tropopause"

From what I've read, it appears certain that warming has occurred--the question is, how much is due to "natural" causes and how much is due to human activity. And multiple studies, following multiple lines of reasoning, conclude that human influence is significant.

I agree that warming has occurred, but I'm more cautious about the "human influence" part, since none of the climate changes so far are in any way extraordinary in the climate record. The only part I would agree has had a human influence would be carbon dioxide levels, but 1) carbon dioxide enrichment has never been shown to cause warming 2) carbon dioxide would probably have risen anyway in response to climate change nearly 1000 years ago and 3) on balance more carbon dioxide (and we're talking a trace gas here) is probably beneficial, producing more growth (good for forests and grasslands) and therefore more food.

There are substantial uncertainties, and some mechanisms may not be precisely addressed in the modeling, so policy decisions will be politically based. what are the consequences of the various decisions?

...is a good question. Certainly from a political point of view, the warming of the 20th Century has seen crop yields rise by one or two magnitudes, more food produced, a reduction in the size of deserts (like the Sahara which is now shrinking) and a near doubling of the life expectancy in most parts of the world.

There are positive and negatives to warming and cooling, but on balance, I'd rather be warming

 

[Brian the Snail]

Now, having dealt with inept analogies on whether carbon dioxide behaves like a blanket,

I think you do Dr. Mahlman an injustice. As far as I can see, he wasn't using "blanket" as an analogy, but as a metaphor.

would you care to cite a single study which shows that carbon dioxide enrichment in fact does cause temperature rise. Refer to any proxy studies done in the climate record, because I can't find any. Notice that your scientific result refers to a modeling result, not actual data from the climate record that demonstrates this.

Poisoning the well. You asked for evidence that carbon dioxide provides warming. I provided it. The model in this case is based on measurements and well established physics, and is testable.

And if these models are invalid, what was the basis of your previous claim that "31 degrees of the greenhouse effect is due to water vapour." How do you know?

Also, if carbon dioxide is such a wonderful blanket of heat, why does the temperature of Mars vary by 200 degrees between day and night despite having a partial pressure of carbon dioxide more than ten times higher than on Earth and similar length of day?

First of all, where did you get 200 degrees from? Is this in celsius or fahrenheit?

To address your question, don't you think it have something to do with the fact that the total atmospheric pressure on Mars is much lower than on Earth? So you're not comparing like with like here. For one thing, Mars has a lot less of the other greenhouse gases, like water vapour (which nobody is denying is important).

Also, regarding CO2, you won't have as much pressure broadening of spectral lines, and this will make a big difference to the amount of radiation absorbed. This means that you can't just look at each gas in isolation, but you need the rest of the atmosphere in there or you don't get meaningful results. So, when you say, in your reply to a_u_p, that "The example of Mars is an excellent test of whether carbon dioxide is a meaningful greenhouse gas in the absense of confounding factors like water vapour", then this is simply untrue. In reality, you have to look at the particular conditions present on each of the planets in detail, and this means using the dreaded modelling techniques you so clearly dislike. (And BTW, the same thing also applies to Venus, which I notice you didn't mention).

 

[Brian the Snail]

The reality is, is that carbon dioxide is a very poor greenhouse gas, re-radiating large amounts of energy out of the atmosphere as well as keeping some heat in.

I don't see what you are getting at here. Surely if it's spontaneous emission, photons will be emitted in all directions? Won't this be true for all gases?

 

[Diamond]

I think you do Dr. Mahlman an injustice. As far as I can see, he wasn't using "blanket" as an analogy, but as a metaphor.

Either way, its inept and inaccurate.

Poisoning the well. You asked for evidence that carbon dioxide provides warming. I provided it. The model in this case is based on measurements and well established physics, and is testable.

No you didn't. If the modelling was tested against real data, then that real data should be available as well. That's what validation means. Carbon dioxide in a laboratory test tube where its contained spacially will behave differently in an atmosphere.

And if these models are invalid, what was the basis of your previous claim that "31 degrees of the greenhouse effect is due to water vapour." How do you know?

How do I know? Its so obvious it needn't be clarified. Its like proving Newton's Laws of Motion or the fact that the sky is blue.

First of all, where did you get 200 degrees from? Is this in celsius or fahrenheit?

I boobed. The temperature range between day and night at the equator is something like 160-170 degrees Fahrenheit, as seen on http://www-k12.atmos.washington.edu/k12/resources/mars_data-information/temperature_overview.html

So I was 30 degrees short. Sue me.

To address your question, don't you think it have something to do with the fact that the total atmospheric pressure on Mars is much lower than on Earth? So you're not comparing like with like here. For one thing, Mars has a lot less of the other greenhouse gases, like water vapour (which nobody is denying is important).

I know we're not comparing like with like. We're looking at one gas in isolation which is why Mars was chosen since it has none of the other confounding factors and has a similar length of day. Its called separating variables and is a common scientific technique of inquiry (see "A Demon Haunted World", Carl Sagan)

Also, regarding CO2, you won't have as much pressure broadening of spectral lines, and this will make a big difference to the amount of radiation absorbed. This means that you can't just look at each gas in isolation, but you need the rest of the atmosphere in there or you don't get meaningful results. So, when you say, in your reply to a_u_p, that "The example of Mars is an excellent test of whether carbon dioxide is a meaningful greenhouse gas in the absense of confounding factors like water vapour", then this is simply untrue. In reality, you have to look at the particular conditions present on each of the planets in detail, and this means using the dreaded modelling techniques you so clearly dislike. (And BTW, the same thing also applies to Venus, which I notice you didn't mention).

I didn't mention Venus, because a) it has large amounts of sulfates in the atmosphere that make it nearly opaque to light and b) it has an extremely slow rotation. I chose a simple example for good reason that it isolates the effect of a single variable on a nice planet-sized scale.

It is possible to measure the effect of carbon dioxide taking into account differences in pressure and distance from the sun. Its still a very poor "greenhouse gas" and the diurnal range of temperature on Mars reflects that, as well as the difference between the average temperature and the effective temperature being far and away the smallest of the inner planets with (significant) atmospheres.

 

[Diamond]

I don't see what you are getting at here. Surely if it's spontaneous emission, photons will be emitted in all directions? Won't this be true for all gases?

Just so, but if someone says that all gases in the atmosphere can be considered to be greenhouse gases, without assessing their relative contribution, then that would undercut your entire argument wouldn't it?

 

[a_unique_person]

Not at all. The example of Mars is an excellent test of whether carbon dioxide is a meaningful greenhouse gas in the absense of confounding factors like water vapour.

The reality is, is that carbon dioxide is a very poor greenhouse gas, re-radiating large amounts of energy out of the atmosphere as well as keeping some heat in.

The partial pressure of carbon dioxide on Mars is more than ten times that of Earth. If there was a significant "greenhouse effect" due to carbon dioxide alone, that's where you'd see it.

Except you don't.

We aren't talking about Mars, we are talking about Earth. I am not scientist who can give you all the facts, but when they say it is a significant factor, I believe them. Significant can mean many things to many people. Have you ever heard an economist squeal when interest rates go up a few percent?

 

[a_unique_person]

Just so, but if someone says that all gases in the atmosphere can be considered to be greenhouse gases, without assessing their relative contribution, then that would undercut your entire argument wouldn't it?

They can, to an extent. That is why scientists are measuring methane emissions from cattle in Australia now, to quantify the amount of this gas being added to the atmosphere.

 

[Diamond]

We aren't talking about Mars, we are talking about Earth.

No, but we are talking about the same gas. There is no "Martian carbon dioxide" only carbon dioxide. The assumption is that the laws of Physics apply equally well on Mars as on the Earth.

I am not scientist who can give you all the facts, but when they say it is a significant factor, I believe them.

I suspend judgement until I see good evidence. Scientific authority may help, but it is not the overriding factor, since some well-credentialled scientists can be very, very wrong.

I am a skeptic of claims that cannot be backed up with good evidence. It always makes me suspicious of a claim, when someone questioning the claim is subject to abuse for even asking, especially when key facts are in doubt (see this thread for further details)

Significant can mean many things to many people.

I go for "can be considered important to consider in a quantifiable way"

Have you ever heard an economist squeal when interest rates go up a few percent?

No. If there's no-one around when interest rates go up, does the economist make a sound?

 

[Brian the Snail]

No you didn't. If the modelling was tested against real data, then that real data should be available as well. That's what validation means. Carbon dioxide in a laboratory test tube where its contained spacially will behave differently in an atmosphere.

Measurements are not restricted to the lab. For example, IR absorption by the atmosphere can be directly measured by satelites.

How do I know? Its so obvious it needn't be clarified. Its like proving Newton's Laws of Motion or the fact that the sky is blue.

I'm glad you now accept the validity of modelling in determining the warming effect of atmospheric gases. So if this is true for water vapour, isn't it also true for carbon dioxide?

I boobed. The temperature range between day and night at the equator is something like 160-170 degrees Fahrenheit, as seen on http://www-k12.atmos.washington.edu/k12/resources/mars_data-information/temperature_overview.html

Sorry, but I can't find where it says this. I don't see data for the equator. However, it does say at one point:

At VL1, 22° N, the afternoon, maximum, summer temperatures reaching a peak of only -12° F, (-25° C). The minimum temperature is -128° F, (-89° C), just prior to sunrise: this is the sub-tropics, during summer! The diurnal cycle is similar to that of Earth on a clear day except for the much greater Martian temperature variation of 113 ° F, (63 ° C).

I know we're not comparing like with like. We're looking at one gas in isolation which is why Mars was chosen since it has none of the other confounding factors and has a similar length of day. Its called separating variables and is a common scientific technique of inquiry (see "A Demon Haunted World", Carl Sagan)

And if he was alive, I'm sure Carl Sagan (as an astronomer) would have told you that often this is simply impossible in observational sciences, since more often than not there's many other factors that come into play. Just like in this case, where there's the pressure broadening problem, and there's plenty of other confounding factors, such as the lack of liquid water on Mars' surface, and different rates of heat transfer within the atmosphere. Again, you have to look at it as a whole, which is why modelling is so important.

I didn't mention Venus, because a) it has large amounts of sulfates in the atmosphere that make it nearly opaque to light and b) it has an extremely slow rotation. I chose a simple example for good reason that it isolates the effect of a single variable on a nice planet-sized scale.

Except it doesn't.

It is possible to measure the effect of carbon dioxide taking into account differences in pressure and distance from the sun. Its still a very poor "greenhouse gas" and the diurnal range of temperature on Mars reflects that, as well as the difference between the average temperature and the effective temperature being far and away the smallest of the inner planets with (significant) atmospheres.

Do you have a source for this, please?