No Other Plausible Reason
The evidence linking carbon dioxide to changes in night-shining clouds is still tentative, Russell said.
But "in all honesty, we don't know of any other plausible reasons why it wouldn't be global climate change," he said.
"If that's true, that says not only are we changing the atmosphere where we're living, we're changing a very remote, rarified part of our atmosphere."
Such far-reaching change means that "we need to be concerned," Russell said.
"If [the cloud changes] are indeed tied to carbon dioxide buildup, here's another confirming reason we should strive to do something about it."
AIM also discovered "dramatic changes" in cloud behavior, said Scott Bailey, AIM's deputy principal investigator.
The data suggest the clouds are highly variable, rotating every five days according to minute shifts in temperature—even as little as 5 degrees Fahrenheit (2.7 degrees Celsius).
"These clouds are exquisite thermometers," he said.
"Now we're able to see the whole life cycle [of a cloud] for the first time," Bailey told National Geographic News.
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