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Discussion > Where is the evidence


Jack Dawkins

Q. Is CO2 a greenhouse gas?
A. Yes and no.

Explain how your research into planetary temperatures supports this assertion.

OK, please explain to me why, when

!. The atmosphere of Mars has a greater mass of CO2 than Earth, and is cloud free
2. The Proportion of CO2 in the atmospheres of Mars and Venus are similar
3 The albedo of Venus is greater than either Earth or Mars

Purely in terms of CO2 that the "average" temperatures of all three are completely different whilst as far as we can tell the climates have been stable for hundreds of millions of years? Because so far I am with Dung, there seems no evidence that CO2 has measurable influence on planetary temperatures and therefore has no influence on climate.

You can check the planetary data on NASA.

Feb 20, 2015 at 11:25 AM | Unregistered CommenterSandyS

I suppose it depends what you mean by measurable ...
The graph I like best (and I've lost it again) is the one that shows the y-axis scaled from the known ground-level minimum temperature to the known maximum temperature and the x-axis representing 1850 to 2014.
You need a magnifying glass to see that it isn't a straight line.
Definitely nothing to see here. We should have moved along years ago!

Feb 20, 2015 at 1:19 PM | Registered CommenterMike Jackson


Does it not occur to you that I am completely aware of what you have said already and that I have reached my current point of view despite those arguments?
You have already researched this subject so congratulations for that but you do not seem to be questioning what you are told. You will have a powerful and persuasive ally in Big Yin; he is a total believer in the science :)

Feb 20, 2015 at 1:27 PM | Registered CommenterDung


We appear to have a similar problem hehe, I have got myself into a discussion with geronimo about what Ice core records show/prove; I know I had some graphs which demonstrate points I want to make but can I find them?? Grrrrr


The points you raise are points I wish I had looked at :) There was somebody on the blog years ago who kept on about Venus proving that this CO2 thing was rubbish. At the time it sounded so 'way out' that I did not take it seriously, methinks I am therefore hoist by my own petard ^.^

Feb 20, 2015 at 1:44 PM | Registered CommenterDung


If you are aware of this empirical evidence - which if you understand, it is hard to reach any other conclusion except that CO2 contributes to the earth being warmer than it would be otherwise - why did you ask the question?

Feb 20, 2015 at 3:23 PM | Unregistered CommenterCurt

What you quoted was not all empirical evidence :)

Feb 20, 2015 at 3:42 PM | Registered CommenterDung


Your post contained the following:

The only mechanism earth has for exchanging energy with the rest of the universe is electromagnetic radiation. Simply put, it receives radiation (UV, visible light, shortwave IR) from the sun, and it emits radiation (longwave IR) to deep space."
What about cosmic rays?

"If the amount of energy in these two power flows does not match, the internal energy of the earth will change (1st Law of Thermodynamics), manifesting itself as temperature change and phase change of water. Nobody, alarmist or skeptic, thinks the earth is out of balance, averaged over its surface and the time of a year, by more than 1 watt per square meter (1 W/m2)."
Considerable amounts of incoming IR are used to power chemical processes such as the removal of Carbon from CO2 by plants and its storage in the earth.
"If the amount of energy in these two power flows does not match, the internal energy of the earth will change (1st Law of Thermodynamics), manifesting itself as temperature change and phase change of water."
The earth is storing the sun's energy all the time without changing the temperature, hence we have coal, gas and oil
Also why is it important that nobody thinks the earth's energy flows are out of balance, does thought equal empirical evidence?
"there are substantial convective and evaporative transfers from the surface"
You can measure these?

Sorry if I get a bit ratty over this subject hehe

Feb 20, 2015 at 4:33 PM | Registered CommenterDung

Dung: OK, I'll bite... What wasn't empirical evidence?

Feb 20, 2015 at 4:33 PM | Unregistered CommenterCurt

It has interested me since I discovered the situation many years ago. If CO2 is the main driver then this is the data to at least give some decent repeatable models/outputs.

Feb 20, 2015 at 4:49 PM | Unregistered CommenterSandyS

Measurements from satellites are indeed empirical data. Big error bars and small numbers resulting from subtracting big numbers from each other leave room for doubt, but empirical data it is.

Although personally I don't care for putting the albedo in as a constant, it's OK as a starting position. But this is a water world.

Also on a personal note, I'm wary of arguments based on other planets when we don't even know what's happening on this one. Water alone could mess up any comparison, never mind rotation rate, which makes a fairly big difference in the earth-moon comparison.

Feb 20, 2015 at 5:29 PM | Unregistered Commenterrhoda

Dung, thanks I think I understand what your saying now, I'd assumed you were saying it had no influence because it wasn't a greenhouse gas. In fact I believe the same thing as you but take a different approach, it has no influence because extra heat in the world's system eventually causes cooling with he introduction of other forcing

I agree there is no record of OC2 causing warming in the ice-cores, but we have to be careful a record that stretches over 600 million years is by definition going to be low bandwidth i.e the individual data points are going to be a long way from each other so the smoothing will hide a lot of information, which means hidden between the data points there could well be periods where CO2 appears to be driving temperature.

However, in the past 150 years we have had two periods which may prove your hypothesis 1910 - 1940 saw half the warming from 1880 to today, but the increase in CO2 from pre-industrial levels didn't justify the increase, while we're in what could be a 20 year pause with an 8% increase in CO2. So yes I believe CO2 is a GHG, but isn't the control nob for the temperature until someone can explain the paradox of warming when CO2 barely increasing and no warming with a substantial increase in CO2.

Does that mean we agree?

Feb 20, 2015 at 5:37 PM | Registered Commentergeronimo


Is there a typo or a missing link in your post? You didn't seem to give any data?

Feb 20, 2015 at 6:55 PM | Registered CommenterDung

My comment of Feb 16 was meant to be lighthearted, if thought provoking. Just to be clear, I am of the opinion that CO2 is indeed a greenhouse gas, albeit a relatively minor one, even on Venus.

As Steven Goddard at his blog Real Science, explains:

If you traveled to Venus and descended into the atmosphere to an altitude of 50km, the atmospheric pressure and the temperature would be similar to that on Earth. This is in spite of the fact that the greenhouse effect at 1 bar on Earth is much stronger – because we have water vapor.

And this is despite Venus being closer to the sun. The high surface temperature of Venus is due not to CO2, but to its very dense, convective atmosphere.

Feb 20, 2015 at 7:00 PM | Unregistered CommenterJack Dawkins


I am extremely worried abut debating anything with you :P

1) You seem to have a mind like a steel vice and I worry that I will suffer permanent damage.

2) In all the situations in which I understand what you are talking about I have ended up agreeing with you and so if I disagree with you I am going against the odds hehe.

I think I need to disagree with you on a minor point and see how it goes ^.^

The mantra is about balancing incoming and outgoing radiation and states that they must balance or the temperature will go up. They use satellites to measure outgoing radiation and are convinced that there is balance.
Their calculations do not take into account the energy used to store Carbon in the earth but still they say there is balance, so where is the error?

Feb 20, 2015 at 7:13 PM | Registered CommenterDung


I would have thought that a guy smart enough for Mensa would be able to do order-of-magnitude calculations. But apparently not.

The fundamental issue is this: There is a gap of about 250 W/m2 (averaged over the earth's surface and a year) between the power the earth receives from the sun and what the earth's surface puts out. This needs to be explained.

Now, you could argue that this is really only 240, or even 200, W/m2, due to errors in measurements, but it is still a huge gap. The problem is that all of the possibilities you cite are multiple orders of magnitude too small to make any difference here.

You cite the sequestering of high-energy coal and the like. But that happened over geological time scales. As we burn these fuels and release their energy thousands (millions?) of times faster than they were formed, this released power is still way to small to matter. (I recently saw a paper that said if we double our rate of use of these fuels 7 more times, so by over a factor of 100 more than now, it will start to matter on the order of a fraction of a W/m2.)

Active photosynthesis can covert a few percent (less than 5%) of the power of sunlight to biomass for a few hours a day under favorable conditions. But this is very short term storage -- most of the stored energy is released within a year to respiration or rotting. What matters is how much stored energy in biomass changes over a year. And if you do the numbers, even accepting that this is growing now (and it probably is), this accounts for a tiny fraction of a W/m2.

The same with other phenomena. (Yes, I ignored the [very steady] 0.07 W/m2 from the earth's core due to radioactive decay and tidal friction.)

Oh, and the idea that the earth is not out of balance by more than 1 W/m2 is based on empirical measurements, most recently the Argo float measurements that provide ocean heat content data. All the arguments about this data involve tenths of a W/m2. They are good arguments, and resolving the uncertainties could tell us a lot, but you have to put their magnitude in context.

When I do my financial planning for retirement, I don't worry about my penny jar. Do you?

Feb 20, 2015 at 9:19 PM | Unregistered CommenterCurt

Polar Beer,
Where are the temperature increases? They ain't happening. Stop with circular bs. The only thing you prove by sticking to simple arguments is that you have a simple mind.

Feb 20, 2015 at 9:52 PM | Unregistered Commenterhunter


I see that I need to change how I describe what I believe (and also change some of it hehe)

First; CO2 is a greenhouse gas and it is having an effect on the temperature of the earth every day, however what it is not doing at the moment is causing the earth to get warmer.
Geological records prove that the effect of CO2 has to be limited, we once had 800,000 ppm of CO2 in the atmosphere but the temp did not spiral out of control; it cooled and over time the CO2 was 'filtered' out of the atmosphere and stored by the earth.
If there is enough CO2 in the atmosphere, ALL the radiation at its 'preferred' wavelength is taken by the CO2 and re emitted at a different wavelength and adding more CO2 has no effect (in further increasing the temp of the earth).
Everyday CO2 is having this constant but limited effect on the temp and the various pieces of equipment you mention are measuring this effect.
When I talk about CO2 having no effect I am incorrect and I should be saying that the effect is maxed out.

Feb 21, 2015 at 1:55 AM | Registered CommenterDung


I think we agree ^.^

Feb 21, 2015 at 2:04 AM | Registered CommenterDung


I think we are actually pretty close to each other, actually. I would be a little more careful and say that we do not have any empirical evidence of the quality necessary to demonstrate that the recent added CO2 is causing additional warming.

But that is a very different statement from saying that we don't have any empirical evidence that the presence of CO2 in the atmosphere leads to warmer temperatures than there would be without any CO2. Making that kind of statement is what gets you snipped at a lot of websites.

Feb 21, 2015 at 2:15 AM | Unregistered CommenterCurt

I agree with Curt's two statements. I usually only ask faux-naif questions but I am able to go as far as 'Nothing much is happening and if anything does, we should (and can) adapt to it'.

Feb 21, 2015 at 2:52 AM | Unregistered Commenterrhoda


I think the description Oxfordshire housewife also comes under the heading faux-naif ^.^

Feb 21, 2015 at 3:01 AM | Registered CommenterDung


In my defence, I never used the phrase "warmer temperatures than there would be without any CO2" :)

I want to apologise for my initial response to your first post; it reads as incredibly arrogant but was a result of being in the middle of more discussions than my old brain can handle at the same time hehe

Feb 21, 2015 at 3:12 AM | Registered CommenterDung

Sorry yes there was meant to be a link to NASA. It's quite a useful and interesting resource.

Feb 21, 2015 at 12:59 PM | Unregistered CommenterSandyS

Curt said:

The fundamental issue is this: There is a gap of about 250 W/m2 (averaged over the earth's surface and a year) between the power the earth receives from the sun and what the earth's surface puts out. This needs to be explained.

I think most here will be aware of the argument that there is a significant mismatch between measured incoming and outgoing energy and therefore the planet should be warming.

But let’s not forget that the entire planet is literally powered by the sun. Incoming solar energy drives the Earth’s weather systems, winds and ocean currents. It also drives the water cycle – evaporation from land and oceans of vast quantities of water. These millions of tonnes of water are then lifted, often to the high upper atmosphere, before falling back to the surface where the cycle starts all over again.

This uses a lot of solar power, so it’s hardly surprising that there’s a mismatch between incoming and outgoing energy.

Just like a heat engine such as an internal combustion or steam engine some of the supplied energy is converted into useful work and there’s a temperature drop across the engine. If there was no temperature drop it would imply a thermal efficiency of 0%, which is not much use to anyone!

Feb 21, 2015 at 2:34 PM | Unregistered CommenterJack Dawkins

Oxfordshire housewife is definitely not true. I live in Texas now. Temporarily. Very temporarily if the visa doesn't happen.

Researching the climate at 33N 97W.

Feb 21, 2015 at 2:34 PM | Unregistered Commenterrhoda