Discussion in 'Earth Science' started by Andre, Oct 31, 2008.
Yes, its gone up approx 30%...to 0.038% of the total atmosphere.
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Why? Is there something we don't know about this stuff?
When we started cutting down forests and planting crops - changing the landscape - did we know that ~8000 years later the CO2 would be at this level?
Or didn't it matter then, so it can't be a problem now? Or "it's not allowed to be a problem"??
(When I use the word "problem", of course I mean: "for us and all the other animals")
That's exactly what several threads on this forum were saying last winter, after the all time melt in 2007.
Then, this summer, both the Russian and Canadian passages opened up, for the first time in thousands of years as far as anyone knows.
You appear to be claiming that such a low percentage of the atmosphere is insignificant.
Are you really claiming that?
Very much so yes.
The most obvious suspect would be humans burning stuff....wood, coal, oil.
Well that explains a lot.
I blame the American high school.
Try this: how many feet of CO2 are over your head right now in the troposphere - that is, at a density profile matching the lower atmosphere over a square inch of the land surface, how thick would a layer of just the CO2 be?
And how much of that was added by fossil fuel combustion since 1900 ?
I thought we just answered that?
The answer would be a number of feet, or meters.
The important numbers are ratios...as we already understand.
No sunspots for a few years so the Earth will continue cooling till we get some more sunspots. If it continues, we could have a mini-Ice Age.
They're only important if you understand them. If you are trying to claim the CO2 in the air has no significant effects on the climate because it's quantity ratio is small, that ratio is misleading you rather than informing you. One standard pedagogical approach to inculcating an idea of the implications of a ratio is to return to absolute quantities.
So: given the same density profile as the air extending, say, 60k feet over your head (or 20k meters, just use round numbers), how many feet of that is CO2?
And would an imagined doubling of that mental image height improve your intuition of the significance of the recent accumulations of CO2 from fossil fuel burning?
So much for the myth of "glacial rebound"...Please Register or Log in to view the hidden image!
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If the ratio of CO2 to other gases is "insignificant", does that mean the atmosphere could have none at all?
(No, it doesn't, actually. Without a significant ratio the planet would be miles deep in thick ice, no complex lifeforms, minimal water vapour in the atmosphere, minimal retention of solar radiation, blah blah)
Theres the difference in your approach...I dont rely on imagination.
The facts at hand indicate a 30% increase most likely caused by human activity. But this is 30% of an extraordinarily tiny ratio of CO2, which is itself only fractionally potent compared to water vapour.
No its actually very significant...significantly tiny.
Your repeated claim that the ratio of CO2 to the other constituents of the atomsphere implies insignificance, is pure fantasy - nothing but imagination on your part. You imagine that such a small ration must be without significance, and incapable of causing large effects. You have not checked, done the calculations, investigated - simply projected, in your imagination, what a small amount .038% of anything is, to how insignificant it must be.
One common approach, when a student fails to comprehend the significance of a ratio, or their misled intuitions make clear that they are not grasping the situation, is to fall back on absolute quantities: build the ratio from its constituents, more easily handled by human intuition.
Thus the question: how much CO2 is that, over your head right now? How thick a layer does it make? What would a doubling of it look like? Just exercises for improving one's grasp of the physical situation.
So, you're implying that it's actually water vapour that drives the warming of the atmosphere? CO2 comes along for the ride, because of all the warming caused by convection of water in the atmosphere?
You may not also realise that this is a completely wrong implication to make? Probably it's based on a significantly tiny understanding of atmospheric dynamics.
We dont have to apply our imagination...merely our reason. Water vapour accounts for 36-66% of the greenhouse effect. The balance is a combination of methane, CO2, and nitrous oxide. CO2 being the least potent and only increasing by 0.008% of the total atmosphere during the industrial age.
So we're talking about a fraction of a fraction of a fraction...simply not significant enough to register.
So you do believe that water vapour is the primary cause of the greenhouse effect?
That reflects a rather minimal grasp of the carbon cycle, what geochemistry is, and why the water vapour is in the atmosphere in the first place. You're someone who clings to ignorance to attack an idea, even though you don't actually understand what you're attacking (with ignorance).
I never studied earth science, but I can read and there's enough in mags like Scientific American to get a good history of the actual science, and what the connection is to geochemistry, which doesn't study the climate so much. Geochemists and geologists have got the wrong idea, or they're in on the big conspiracy too, huh?
Sure...straight out of the wiki article on greenhouse gases:
"Water vapor is a naturally occurring greenhouse gas and accounts for the largest percentage of the greenhouse effect, between 36% and 66%. Water vapor concentrations fluctuate regionally, but human activity does not directly affect water vapor concentrations except at local scales (for example, near irrigated fields)."
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