根據美國太空總署（NASA）及約翰霍普金斯大學（Johns Hopkins University）科學家所提出的研究報告顯示，越來越多的溫室氣體排放將減緩甚至延後地球上某些地區「下平流層」（lower stratosphere）臭氧層的修復狀況。
地球臭氧層曾在20世紀由於人類使用冷煤等耗損臭氧層物質而受到傷害，正在科學界預期狀況已逐漸好轉之際，研究卻發現，未來的臭氧層將和過去的臭氧層有所不同，因為溫室氣體會改變大氣中的動態歷程。
大量溫室氣體會使距離地表9.6公里的大氣層暖化，但同時也讓距地表29到50公里的「上平流層」（upper stratosphere）冷卻。這個冷卻作用會使冷媒等臭氧層破壞物質（ozone depleter）的化學反應變慢，讓臭氧層的自然生成速度高過受破壞的速度。
NASA科學家進一步解釋，「然而，越來越多的溫室氣體累積在一起，也可能會改變赤道到南北極之間平流層氣團的對流情形。」
科學家說，地球中緯度地區上空的臭氧層可能會「過度修復」；換句話說，臭氧層修復後的濃度，會比這區受到大量氟氯碳化物（CFCs）、海龍（halons）、四氯化碳、三氯乙烷與氟氯烴化合物（HCFCs）破壞之前的濃度還要高。
然而在赤道地區，平流層對流的改變則會讓臭氧層無法完全恢復。
「大部分臭氧與全球變遷相關研究，都將重點放在上平流層的冷卻作用，但我們發現對流也是相當重要的因素。我們不該只關注其一，而應兩者兼具。」馬里蘭大學巴爾的摩分校「戈達德地球科學與技術中心」（Goddard Earth Sciences and Technology Center）的大氣科學家，也是該研究的主筆李豐（Feng Li，音譯）如此表示。
上述研究發現主要是來自精細的電腦模擬，其中考量了大氣中的化學作用、風的變化以及太陽輻射變動等因素。
Increasing greenhouse gases would delay or even postpone the recovery of ozone levels in the lower stratosphere over some parts of the planet, according to new research by scientists from NASA and Johns Hopkins University.
Earth's ozone layer is predicted to recover from the destruction caused by the use of refrigerants and other ozone-depleting chemicals in the 20th century. But the studies find that the ozone layer of the future will be different from the ozone layer of the past because greenhouse gases are changing the dynamics of the atmosphere.
While the buildup of greenhouse gases warms the atmosphere from Earth's surface up six miles high, it cools the upper stratosphere - the atmospheric layer between 18 and 31 miles up.
This cooling slows the chemical reactions that deplete ozone in the upper stratosphere and allows natural ozone production there to outpace destruction by refrigerants and other ozone depleters.
But the accumulation of greenhouse gases also changes the circulation of stratospheric air masses from the tropics to the poles, NASA scientists explain.
In Earth's middle latitudes, that means ozone is likely to "over-recover," the scientists said, growing to concentrations higher than it was before the mass production of chlorofluorocarbons, halons, carbon tetrachloride, methyl chloroform and hydrochlorofluorocarbons destroyed it.
In the tropics, stratospheric circulation changes could prevent the ozone layer from fully recovering.
"Most studies of ozone and global change have focused on cooling in the upper stratosphere," said Feng Li, an atmospheric scientist at the Goddard Earth Sciences and Technology Center at the University of Maryland Baltimore County, Baltimore, Maryland and lead author of the study. "But we find circulation is just as important. It's not one process or the other, but both."
The findings are based on a detailed computer model that includes atmospheric chemical effects, wind changes, and solar radiation changes.
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