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pleiades's avatar

As it pertains to global warming, what do you think about this statement (inside for details)

Asked by pleiades (6584points) May 25th, 2013

I read this on FaceBook.

It said from

“NASA debunks global warming claiming carbon dioxide actually cools the atmosphere”

Yes NASA can say it cools the atmosphere, but the Average Joe doesn’t know how cool atmosphere affects density and pressures.

Does a cool atmosphere really mean a “cooler” planet and one with less dramatic weather?

Or is this bologna information?

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3 Answers

BhacSsylan's avatar

It’s total bunk. If an agency like NASA was in denial of global warming, you’d hear a lot more about it. What that says is something we’ve known for a long time: CO2 takes in solar energy, and radiates it as heat. When in the upper layers of the atmosphere, this results in lots being radiated out of our atmosphere, because the radiation doesn’t have direction, and there’s nothing above it to stop the radiated energy. Think of it like a mirror. The uppermost parts of the atmosphere reflect some energy back outwards. But it also reflects energy coming up back down. Hence ‘greenhouse’. And plus most of our production of CO2 is in the lower atmosphere, where it serves a slightly different role.

Also, for reference (yours is broken), this seems to be the report that has all these climate change denialists in a tizzy: Specifically the line ”“Carbon dioxide and nitric oxide are natural thermostats,” explains James Russell of Hampton University, SABER’s principal investigator. “When the upper atmosphere (or ‘thermosphere’) heats up, these molecules try as hard as they can to shed that heat back into space.” ” Think about the way that’s stated. Does it sound like him making some great revelation that puts him at odds with ~%95 of scientists? Or does it sound like he’s simply explaining a well-understood effect?

Edit: Also, I noticed a footnote that puts it in even better perspective: ”“Heat radiated by the solid body of the Earth is very large compared to the amount of heat being exchanged in the upper atmosphere. The daily average infrared radiation from the entire planet is 240 W/m2—enough to power NYC for 200,000 years.” The fact that the upper atmosphere’s CO2 happens to radiate off some heat from space is a drop in the bucket.

ragingloli's avatar

The Nasa article says that the gases reflect much of the radiation back into space yes. But that is the upper atmosphere.
What is relevant to global warming is the lower atmosphere.
In that case, the CO2 and other GHGs reflect thermal radiation from the surface back down. The higher the concentration of GHGs in the lower atmosphere, the higher the reflection rate, and the higher the warming of the lower atmosphere.

By the way, the upper atmosphere, also called thermosphere, is the layer of the atmosphere in which the ISS orbits. Just to put it into perspective.

ETpro's avatar

The thermosphere is way, way up. It is actually quite hot all the time due to interaction with solar and cosmic radiation. It can be as high as 1500 °C, though the individual gas molecules at that altitude are so far apart it doesn’t make a much sense to even talk about its temperature. Other that protecting Earth from sudden spikes in solar radiation as the referenced article was describing, the troposphere has little effect on the surface temperatures of Earth. If it did, far from ending Global Warming, it would turn Earth into a blast furnace with temperatures exceeding those on Mercury.

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