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Thermosphere Contraction Puzzles Scientists
The thermosphere layer of earth's atmosphere begins 80 to 90 kilometers above the surface and extends several hundred kilometers into the sky; it is the home to numerous satellites and the International Space Station. It is known that the thermosphere occasionally cools and contracts, but a recent study of satellite orbital decay (due to light atmospheric drag) found that the contraction during 2008 and 2009 was significantly more severe than expected, leaving researchers at a loss for how to explain it. From Space.com:
"This type of collapse is not rare, but its magnitude shocked scientists. 'This is the biggest contraction of the thermosphere in at least 43 years,' said John Emmert of the Naval Research Lab, lead author of a paper announcing the finding in the June 19 issue of the journal Geophysical Research Letters. 'It's a Space Age record.' The collapse occurred during a period of relative solar inactivity — called a solar minimum from 2008 to 2009. These minimums are known to cool and contract the thermosphere, however, the recent collapse was two to three times greater than low solar activity could explain."
CO2 is denser than air so naturally the atmosphere compacts under gravity as the density increases.
Utterly incorrect. CO2 levels rising dramatically doesn't mean the percentage composition of CO2 in the atmosphere has changed by a large number. The atmosphere is still less than .5% CO2 today; even if it had started at 0% CO2, adding .5% concentration of something only half again as heavy (or dense, if you prefer; not that dense and heavy are synonyms but either way my point stands) as the vast majority of the atmosphere would not logically explain "the biggest contraction of the thermosphere in at least 43 years" without some serious synergy compounding the effect of that minimal impact on atmospheric density.
Furthermore, a given swath of the atmosphere is all roughly the same density; it's not like there's this big fat pocket of air that weighs 0.1 g/L and this other pocket a mile away at the same altitude that weighs 0.19 g/L. Diffusion dictates that CO2 could change the density of the air only as much as it changes the average density of the entire atmosphere (at a given altitude) once completely diffused into all the other stuff. You could jack the atmosphere up to 10% CO2, 20 times what it's ever been in the last billion years, and I doubt you could explain these contractions with simply density arguments.
Also, TFA mentions CO2 - not in any conjunction whatsoever with your insane reason for mentioning it, but it does mention CO2 - and says "Even when we take CO2 into account using our best understanding of how it operates as a coolant, we cannot fully explain the thermosphere's collapse." Note that they're talking about CO2 cooling the upper atmosphere, not about density.
Whoever marked the parent as informative is a moron.
Definitely, and there's at least 4 of them apparently. 4 people who felt compelled to tell us this was good information but couldn't remember anything about 101 level chemistry. How the fuck did they pretend to know it was good information if they can't see through something that stupid?
I wonder by which definition you say the Arctic ice cap is in "decline", but not melting?
The Antarctic ice sheet is shrinking, not growing. It's losing volume, which is the only significant definition of size when one considers climate issues. It's losing volume the only way a polar ice cap can lose volume, by melting. But, of course, you'll never know this if you have only one news source.
Warmer oceans cause increased water evaporation, which then precipitates as snow or rain. Considering that a large part of Antarctica is still well below freezing point, it's only natural that *some* regions of Antarctica have had more snowfall caused by global warming. Yes, global warming does cause both more snowfall and colder winters. Which is more than offset by hotter summers and increased ice melting.