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Post by Ratty on Feb 24, 2014 9:46:47 GMT
On a seniors' forum where I lurk, this "proof positive" demonstration experiments of the greenhouse effect was posted: CO2: A Natural By-Product of NatureAny scientists out there who can assist me with a rebuttal?
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Post by douglavers on Feb 24, 2014 10:27:17 GMT
1. CO2 mainly absorbs in two bands, at about 5 and fifteen microns. From memory, the first 22 ppm in the atmosphere is responsible for about half its absorption, the next 22 ppm half of the remainder etc. Its like putting one sheet after another of smoky glass in a window. Once you get to 400 ppm, extra CO2 has negligeable additional effect. Your window is completely black.
This is called saturation. We have already achieved this. It is why the earth did not go into a heat death in the geological past when the concentration was over 2000 ppm.
2. Water vapour is by far the most important greenhouse gas. The human race has absolutely no control over its atmospheric concentration.
I think some of the water absorption bands overlap those of CO2.
3. I may be wrong here, but I have an idea that the "tropical stratospheric hot spot" predicted by every climate model comes from the heating effect of absorbed radiation. As CO2 concentrations rise, more heat absorption..................
Unfortunately, no-one can find this hot spot. To paraphrase a legendary scientist, no matter how elegant or beautiful a theory, if it does not match observation, its wrong.
Besides which, in the last 15 years CO2 atmospheric concentration has risen by about 10%. Nothing much has happened to planetary temperatures.
When I was at university, people would have been scurrying around looking for a better theory, which did not involve CO2.
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Post by karlox on Feb 24, 2014 11:44:43 GMT
On a seniors' forum where I lurk, this "proof positive" demonstration experiments of the greenhouse effect was posted: CO2: A Natural By-Product of NatureAny scientists out there who can assist me with a rebuttal? Not very scientist but here goes my layman´s questions on this subject: -Are CO2 concentrations in troposphere higher as we proceed from Estratosphere to Earth´s Surface through a denser atmosphere? If so -I suppose- could that configuration be replicated in lab testings?. Besides atmosphere is an open membrane system exchanging energy, nothing like a shut room... - Got the feeling that water vapour is the clue. Once admitted H2O is by large main greenhouse gas, How could we elaborate a theory on CO2 or NH4 likely impact on Temps without fully understanding variations and distribution of H20 and cloud cover throughout the ages? - Are really feedbacks -negative or positive- fully understood? Got the feeling land-ocean-atmosphere´s got multiple crossed mechanisms whose triggering threshold and scope are not fully understood... Real LAB -our planet Earth- is by far a much more complicated "experiment" that simple ones depicted. And nobody denies CO2 a green-house effect, that´s not the point! And most layman´s questions I have: How could finally affect Earh´s Mean Temp any extra Heat entering Polar Areas -ocean or atmospheric warmth? Somehow does not Heat radiates into space more easily around Poles areas? (I would appreciate a comment on this, and hope not to look too stupid!)
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fred
New Member
Posts: 48
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Post by fred on Feb 24, 2014 12:31:18 GMT
We measure Co2 in the atmosphere, do we measure water in the same way. Is there a way of giving levels similar to Co2 like H2O molecules per parts per million???
This would also give some indication running along side Co2 and CH4 to see what the effects of variations in concentration have.
Apart from the humidity being so many % water is never mentioned. Water is such a strange compound with many facets it must be difficult to deal with in the climate sense.
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Post by sigurdur on Feb 24, 2014 15:42:45 GMT
For some reason, no sound on the video on my puter. Good comments above, one thing they missed tho is that plants perform better the higher the CO2 goes till around 1200ppmv. Plants evolved during a time of higher CO2, and are actually CO2 deficient today. Another fact to add to the confusion.....
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Post by karlox on Feb 24, 2014 17:15:17 GMT
We measure Co2 in the atmosphere, do we measure water in the same way. Is there a way of giving levels similar to Co2 like H2O molecules per parts per million??? This would also give some indication running along side Co2 and CH4 to see what the effects of variations in concentration have. Apart from the humidity being so many % water is never mentioned. Water is such a strange compound with many facets it must be difficult to deal with in the climate sense. I figure it out that: -Comparing water vapor vs CO2: SATURATION is something we don´t have to care about with CO2, while basic for our life regardin water (so relative humidity is an important figure not applicable to CO2? -Freezing point either... and that makes a BIG difference (water is SO special) -atmosphere water content varies largely with latitude and altitude and humid air masses evolve and move: that´s weather. CO2 gas is much more evenly distributed in atmosphere than water (though I don´t know yet the answer to my question "CO2 ppm layers change with altitude?)
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Post by karlox on Feb 24, 2014 17:19:49 GMT
Regarding Water Vapor we can learn something taking a look at Mars also: Until now, it was generally assumed that such supersaturation cannot exist in the cold Martian atmosphere: any water vapour in excess of saturation was expected to be converted immediately into ice. However, the SPICAM data have revealed that supersaturation occurs frequently in the middle atmosphere – at altitudes of up to 50 km above the surface – during the aphelion season, the period when Mars is near its farthest point from the Sun. Extremely high levels of supersaturation were found on Mars, up to 10 times greater than those found on Earth. Clearly, there is much more water vapour in the upper Martian atmosphere than anyone ever imagined. It seems that previous models have greatly underestimated the quantities of water vapour at heights of 20–50 km, with as much as 10 to 100 times more water than expected at this altitude. ESA ORBITER DISCOVERS WATER SUPERSATURATION IN THE MARTIAN ATMOSPHERE
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Post by Ratty on Feb 25, 2014 11:24:32 GMT
Thanks you all ..... I should be able to piece together something to stir up the seniors' forum.
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Post by nautonnier on Feb 25, 2014 11:57:32 GMT
We measure Co2 in the atmosphere, do we measure water in the same way. Is there a way of giving levels similar to Co2 like H2O molecules per parts per million??? This would also give some indication running along side Co2 and CH4 to see what the effects of variations in concentration have. Apart from the humidity being so many % water is never mentioned. Water is such a strange compound with many facets it must be difficult to deal with in the climate sense. The way it is done is to provide a measure of 'Precipitable Water' or 'Total Precipitable Water' in a column of air over a point. The link gives more references. The main issue is the AGW hypothesis which is that CO2 causes a rise in air temperature leading to more water vapor evaporating. CO2 on its own has a very weak effect and the infrared bands it 'absorbs' in (it actually almost immediately re-emits the radiation) is almost all in the same infrared wavelength band as water vapor. So the more water vapor in the atmosphere is meant to be the _Real_ cause of global warming. The models all show this increase in water vapor 'forcing' leading to a tropical tropospheric hotspot. This hotspot does not exist in the real world atmosphere and believe me it has been searched for. The actual atmospheric water vapor levels have not been rising as predicted (and if you think temperatures have been fiddled with you should see what they do to atmospheric humidity). So the net result is that the hypothesis has been falsified - no hotspot therefore the models are incorrect.
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Post by icefisher on Feb 26, 2014 2:22:50 GMT
On a seniors' forum where I lurk, this "proof positive" demonstration experiments of the greenhouse effect was posted: CO2: A Natural By-Product of NatureAny scientists out there who can assist me with a rebuttal? The demonstration does not support the conclusion. "If the scientist was surrounded by carbon dioxide he would get hotter". No evidence of that is presented and why would an object need to be surrounded by CO2 to not warm? All that is occurring in the demonstration is the gases are eliminating heat contrast and presenting instead a uniform field of radiation. Since they are probably being released from a pressurized container that was at room temperature, the greenhouse gases are probably also absorbing heat because they are relatively cold from being depressurized. That heat absorption can be seen as there remains a small amount of contrast between the environment and the gases continuing to be released from the pressurized vessel.
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