Greenhouse Effect Experimental Designs

[BrianG]

Folks,

 

The only thing stopping me, and most people IMO, from accepting [ce]CO2[/ce] emission restrictions to mitigate climate change is the lack of experimental tests. I offer this forum for your suggestions, and criticism.

 

Here are the only three experiments I've seen:

 

Pico Technology Experiment: Global Warming

 

Experiment - The Greenhouse Effect

 

Is the Earth Warming?

[BrianG]

Ideally, a climate effect greenhouse gas experiment would be a randomized series of controlled GHG (greenhouse gas) release and captures. Let's work on those two areas.

 

Release mechanisms:

 

A giant coal furnace with emission controls and measurements. The benefit would be good control over the amount of [ce]CO2[/ce] released. The disadvantage would be, too slow to emit large amounts of [ce]CO2[/ce].

[JMJones0424]

Why do you think that your results would be any different than the first two experiments you linked to?

 

Is it a matter of scale? If so, why would your proposed experiment have any more bearing than the linked experiments to global warming through increased carbon dioxide levels?

 

Is it a matter of source of carbon dioxide? I can't imagine why, but at least this could be considered a variable. Would it not be more feasible to capture a small portion of emissions from a coal power plant and recreate experiments like those you posted. I don't immediately have a source to link, but I think I remember reading that a large portion of carbon dioxide emissions comes from burning wood. It would be far simpler to just capture emissions from a small fire and test. In fact, I did this a few decades ago as a science experiment in middle school. However, as pointed out by my teacher later, I failed to remove the moisture content from the gases produced from combustion, so my results did not exactly correspond to what you would get if using carbon dioxide alone.

 

Is it a matter of carbon dioxide concentration? If so, wouldn't it be far easier to use bottled gases to create the concentrations you wish to test?

 

I am not trying to be argumentative, I truly wish to know why you feel your proposed experiment would have any more or less relevance than the first two you linked to.

[BrianG]

Lab experiments are good only for measuring the greenhouse effect. The experiments I've linked produce about a [math]5\celsius[/math] temperature change from 370ppmv [ce]CO2[/ce] to 100% [ce]CO2[/ce], or you could say the [ce]CO2[/ce] concentration doubles 12 times to get a [math]5\celsius[/math] temperature change. This is far, far lower than the IPCC predicts and better experiments will help quantify the greenhouse effect. JMJones0424's very helpful suggestion to vary the concentrations of [ce]CO2[/ce] in the vessels, even swap them, would eliminate error from the apparatus and help quantify the effect.

 

The climate is a complex, chaotic system, there are feedbacks that have never been tested. A field experiment will reproduce the real world effects of carbon dioxide on climate. It's possible that the effect of [ce]CO2[/ce] on any warming trend we might observe is negligible, but a field experimental test would give us certainty of cause, and quantify how much [ce]CO2[/ce] causes how much warming. A field experiment would have to release a large amount of [ce]CO2[/ce] into the atmosphere and measure air temperature change. Ideally, it would remove the [ce]CO2[/ce] and measure again.

[freeztar]

Lab experiments are good only for measuring the greenhouse effect. The experiments I've linked produce about a [math]5\celsius[/math] temperature change from 370ppmv [ce]CO2[/ce] to 100% [ce]CO2[/ce], or you could say the [ce]CO2[/ce] concentration doubles 12 times to get a [math]5\celsius[/math] temperature change. This is far, far lower than the IPCC predicts and better experiments will help quantify the greenhouse effect. JMJones0424's very helpful suggestion to vary the concentrations of [ce]CO2[/ce] in the vessels, even swap them, would eliminate error from the apparatus and help quantify the effect.

 

From the first link you posted:

 

Even over a small time period such as 20 minutes we are still able to get a difference of 4 degrees in temperature between the two samples. Students may not be impressed with such a small temperature difference in the lab. However, it needs to be stressed that scientists are in general agreement that an average increase of just 2 degrees celsius across the planet could have catastrophic effects on crop production and cause sea levels to increase significantly resulting in major flooding.

 

The second link shows a temperature difference of 6 degrees celsius after only 20 minutes. Does that not seem significant to you?

 

The climate is a complex, chaotic system, there are feedbacks that have never been tested. A field experiment will reproduce the real world effects of carbon dioxide on climate. It's possible that the effect of [ce]CO2[/ce] on any warming trend we might observe is negligible, but a field experimental test would give us certainty of cause, and quantify how much [ce]CO2[/ce] causes how much warming. A field experiment would have to release a large amount of [ce]CO2[/ce] into the atmosphere and measure air temperature change. Ideally, it would remove the [ce]CO2[/ce] and measure again.

 

And how would you propose this is done, especially the removal part?

[BrianG]

Why did the experiments last only 20 minutes? These are the best I've found, I'd guess it reached thermal equilibrium, maybe the temperature change began to close. Can you find any better tests than these? The temperature change is far, far below IPCC predictions.

 

I've already proposed a super large coal furnace to release carbon dioxide, what would you suggest to remove it?

[modest]

Lab experiments are good only for measuring the greenhouse effect. The experiments I've linked produce about a [math]5\celsius[/math] temperature change from 370ppmv [ce]CO2[/ce] to 100% [ce]CO2[/ce], or you could say the [ce]CO2[/ce] concentration doubles 12 times to get a [math]5\celsius[/math] temperature change. This is far, far lower than the IPCC predicts and better experiments will help quantify the greenhouse effect.

 

I addressed this in a previous thread. It, apparently, didn't take.

 

The absorbance of a CO₂ container is,

[math]A = \varepsilon \ell c[/math]

where A is absorbance, [math]\varepsilon[/math] is molar absorptivity, [math]\ell[/math] is path length, and [math]c[/math] is concentration.

 

Assume you have 2 containers. One is a kilometer tall (1,000 meters) and the other is a meter tall. Assume they are filled with a gas where [math]\varepsilon[/math] = .01. The larger box starts with a concentration of .2 (20 %) and is doubled to 0.4 (40%). How much does the absorbance change?

[math]A = \varepsilon \ell c[/math]

[math]A_1 = (.01) (1000) (.2) = 2[/math]

[math]A_2 = (.01) (1000) (.4) = 4[/math]

The absorbance changes by 2. Will the smaller box have the same change in absorbance if it has the same change in concentration?

[math]A = \varepsilon \ell c[/math]

[math]A_1 = (.01) (1) (.2) = .002[/math]

[math]A_2 = (.01) (1) (.4) = .004[/math]

No, the change in absorbance is 0.002 for the smaller box. The temperature change is a function of absorbance where the greenhouse effect is concerned, not concentration. Concentration is linearly related to absorbance meaning that doubling the concentration in both containers above doubled the absorbance, but if you are dealing with 2 different containers of two different sizes then you must take the path length into consideration.

 

Let me say again—doubling the concentration of each container will double the absorbance of each. But, doubling the concentration of the smaller container does not give you the change in absorbance of the larger container as your method assumes it does.

 

JMJones asks some good questions. Can you answer them?

 

~modest

[BrianG]

...—doubling the concentration of each container will double the absorbance of each. But, doubling the concentration of the smaller container does not give you the change in absorbance of the larger container as your method assumes it does.

 

JMJones asks some good questions. Can you answer them?

 

~modest

JMJones asks some excellent questions and I've tried to answer them, can you help? What do you think I've missed?

 

A good experimental test of the greenhouse effect would use containers of identical size, it would even swap the concentrations to ensure we're not seeing an artifact from the container.

 

In the real world, climate has feedbacks. These feedbacks have never been experimentally tested by adding or removing greenhouse gas. The results in the real world might be drastically different from results in a test tube, just as medicinal drugs are never tested in a test tube, alone.

[JMJones0424]

The climate is a complex, chaotic system, there are feedbacks that have never been tested. A field experiment will reproduce the real world effects of carbon dioxide on climate. It's possible that the effect of [ce]CO2[/ce] on any warming trend we might observe is negligible, but a field experimental test would give us certainty of cause, and quantify how much [ce]CO2[/ce] causes how much warming. A field experiment would have to release a large amount of [ce]CO2[/ce] into the atmosphere and measure air temperature change. Ideally, it would remove the [ce]CO2[/ce] and measure again.

 

My questions were based on the assumption that the problem you had was that you doubted that carbon dioxide was a greenhouse gas. Carbon dioxide's properties are well documented. The test THAT carbon dioxide is a greenhouse gas is simple and can be done by any ten year-old. Your statement that I have quoted does seem to me to have some merit, but I can not conceive of any real-world test capable of modeling all the complexity of the global climate system and the effects of increased carbon dioxide levels. However, just as it is possible with a sufficiently accurate computer model to design an aircraft without a wind tunnel, it is (theoretically?) possible to model the global climate without having our own test planet to play with. The question is of course how accurate are our computer models? I can not begin to give an appropriate answer. I don't think you've tried to show any flaw in the models, but rather have just cast doubts upon their veracity. I would like to see climate change skeptics put as much effort into designing more accurate climate models as they do attacking those trying to produce accurate models. But that would require more effort than denying.

 

I do not think that your proposed experiment is large enough to contain the relationships and feedback loops of the global climate. What about your design is any different than the untold thousands of coal power plants that we already have active? How do you propose isolating the "test climate" from the rest of the world?

[BrianG]

I don't doubt carbon dioxide is a greenhouse gas, I merely want to quantify it's effect on climate.

 

I don't propose isolating a "test climate" I propose a field release or capture of GHG and subsequent measurement. This experiment could be replicated or repeated as necessary, to find the effects of CO₂ on climate. We could then discover any climate feedback mechanisms that amplify or reduce the greenhouse effect.

 

Would you agree computer models are useless to test the effects of unknown feedback mechanisms?

 

All I'm proposing is experimental tests for climate change mitigation.

[JMJones0424]

It is not obvious to me that computer models can not help to identify currently unknown feedback mechanisms, but I am more than willing to concede that it is hard to design a computer model to test for the unknown.

 

However, are we not currently doing the experiment you propose around every coal power plant, at the tail pipe of every internal combustion engine, and around every wood fire across the planet? I don't understand how your experiment is a test of anything more than we are already measuring. And I don't understand why it wouldn't be necessary to isolate a test climate from the rest of the world if you were trying to run a real world test. Maybe I just don't understand your proposed test. Can you explain exactly how you propose the test to be carried out?

[BrianG]

...

However, are we not currently doing the experiment you propose around every coal power plant, at the tail pipe of every internal combustion engine, and around every wood fire across the planet? I don't understand how your experiment is a test of anything more than we are already measuring.

 

Scientific control - Wikipedia, the free encyclopedia

 

When people burn coal for warmth, is the cold climate causing CO₂ emissions? I've found this fallacy a hundred times, we aren't controlling variables when we drive to the supermarket or run a coal power plant. In no way, can burning fossil fuel for energy, be considered an experiment. For a science forum, you guys don't have much faith in the experimental method.

 

And I don't understand why it wouldn't be necessary to isolate a test climate from the rest of the world if you were trying to run a real world test. Maybe I just don't understand your proposed test. Can you explain exactly how you propose the test to be carried out?

 

I propose two experiments, a lab experiment to isolate and quantify the greenhouse effect on temperature and a field experiment to identify climate feedbacks. The purpose of this thread is to propose those experiments.

 

How about this, identify and measure several coal seams, inject oxygen and light them on fire as quickly as possible. Then measure climate change after a massive release of CO₂. To remove GHG from the air, move a few million trees onto barren land, water and care for them while measuring their growth and climate change. Or enlarge and use a proposed carbon capture and sequestration facility to remove carbon dioxide from the air, and measure the effect.

 

We used to think malaria was caused by bad air, further research found mosquito vectors. Experimental tests are the heart of science, they are the best way to find truth.

[CraigD]

Ideally, a climate effect greenhouse gas experiment would be a randomized series of controlled GHG (greenhouse gas) release and captures. Let's work on those two areas.

 

Release mechanisms:

 

A giant coal furnace with emission controls and measurements. The benefit would be good control over the amount of [ce]CO2[/ce] released. The disadvantage would be, too slow to emit large amounts of [ce]CO2[/ce].

If I understand what you’re proposing, Brian, it’s to build a giant coal furnace venting into the Earth’s atmosphere.

 

In addition to the disadvantage you list, “too slow to emit large amounts of [ce]CO2[/ce]”, I can see another: prohibitively expensive.

 

The cheapest available coal costs about US$10/ton, the average about $40 You don’t state by what amount you propose to increase output of what greenhouse gases, but taking as an example that you want to increase [ce]CO2[/ce] output by 10% of that currently produced by coal furnaces, with the current world consumption of coal at about 7 billion tons, the annual cost of coal would be about $28 billion, assuming the increase in demand for coal didn’t cause its price to increase. By comparison, NASA’s annual budget is about $18 billion.

 

Actually building the giant furnace would not, I think, be prohibitively expensive, as it doesn’t need to do what most coal furnaces do, generate electricity. It could be built taking advantage large natural caves and of cheap materials. My guess would be cost of construction would be about equal to a year’s fuel cost, say about $30 billion.

 

Practically speaking, I don’t see how such a thing could be funded. It would, I’m certain, not be supported by the large nation’s governments, who have pledged to reduce, not purposefully increase, greenhouse gas emissions. Private investors would be unlikely to support it, as since it doesn’t produce power or any other sellable commodity, it has a guaranteed zero return on investment.

 

A serious non-engineering problem with this is that, as mentioned above, none of the world governments would support it, and all would consider it an act of large-scale eco-terrorism. You’d have to build it in a country that would permit it – a poor nation with a good sea port would do – but such a nation would have little chance of preventing the large nations from simply bombing the giant furnace before you could build it, and seizing and imprisoning everyone involved in the enterprise.

 

All things considered, I can only imagine a few interpretations of Brian’s post:

• I misunderstand what Brian proposes, and he doesn’t propose building this furnace on Earth
  
• Brian believes the large nations’ would support such a thing
  
• Brian is joking
  

 

If this is a joke, I’ll join in by suggesting that the experiment could more practically be done just by setting fire to everything on Earth that will burn – oil wells, coal mines, and, for good measure, woodlands and cities. Such an act of worldwide arson would be less expensive than building a huge furnace and buying fuel for it, and would emit lots more [ce]CO2[/ce] much more quickly.

 

Seriously, an obvious way that this experiment can be done, and has in fact already been done, is to measure the emissions of representative samples of existing fuel-burning plants and machines, count their numbers, perform a similar measurement and count of natural sources, and calculate their total output of whatever gases and particles we care to measure. Combined with measurements of natural (and a small number of artificial) absorbers (AKA sinks) of gasses and particles, this data, combined with basic science and paleoclimatological records, have allowed the worldwide scientific community to conclude that human-made gas emissions are responsible for a significant and ongoing increase in average global temperature.

[BrianG]

Wow, you really don't like that experiment. Your "experiment" has no controls, it's not an experiment at all, it's just power generation.

 

Instead of building a coal furnace, it would be far cheaper to burn the coal where it is. Mine vents into an existing coal seam, estimating the amount of coal, filling the vents with oxygen, and light it on fire. If a chimney vent was controlled, some emission filters could eliminate pollutants and measure the amount of CO2 ₂ released. Closing the vents and chimney would allow control over the amount of CO₂ released.

 

This would eliminate the expense of transport and the furnace, and probably reduce the expense of mining the coal, as the tunnels need not be designed to move the coal. Perhaps this experiment could cost less than a few billion dollars.

[modest]

To eliminate a variable and setup a control one of the test runs could involve isolating the atmosphere from CO₂-sequestering media on the ground by wrapping the planet in plastic wrap. :)

 

~modest

[BrianG]

Shutting down and opening CO₂ sinks in a controlled, measured plan would allow us to test the effect of increased CO₂ without having to add additional carbon dioxide to the air. That's a brilliant idea, thanks!

[modest]

That's a brilliant idea, thanks!

 

No trouble. The difficult part would be isolating the ocean from the atmosphere. It would be hard to plastic wrap it because it's water. But, the problem could be solved easily enough by making a whole bunch of Jello (gelatin powder) and slowly pouring it mid-pacific while whisking the ocean vigorously. Once the ocean turns gelatin we could wrap it in plastic thus achieving the experiment.

 

And it would taste good too.

 

~modest