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Good news! Scientists say the Antarctic ozone hole is on the road to recovery.

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The amounts of ozone-depleting substances grew rapidly in our atmosphere in the 80s and early 90s,

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but had stopped growing in late 90s because of the 1987 Montreal Protocol.

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As levels of these manufactured chemicals have decreased in the last 14 years

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the ozone hole has seen a slight improvement.

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Today, satellite observations by NASA and NOAA show the peak size of this year’s ozone hole

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measured 9.3 million square miles—an area roughly the size of North America.

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This area is smaller than holes observed in past years

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and significantly less than the largest hole on record.

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But scientists say the decrease of ozone-depleting substances

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isn’t the only factor that has contributed to these improvements.

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Rising temperatures in an upper layer of the atmosphere known as the stratosphere may also play a role.

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Colder temperatures over the polar regions have been shown to promote ozone depletion

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while warmer temperatures lead to increased ozone.

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Years with warmer temperatures generally had smaller holes

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while colder temperatures had larger holes.

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So how much of the ozone hole’s recovery is due to rising temperatures

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versus decreasing levels of manufactured chemicals?