The ozone hole is a dramatic thinning of the ozone layer over Antarctica.

The ozone layer is like sunscreen, blocking harmful ultraviolet energy from reaching the surface.

Scientists expect the ozone hole to shrink back to the size it was in 1980 by approximately 2070.

Thanks to unusually warm temperatures high above Antarctica this month, the ozone hole shrank to its smallest size on record, scientists reported Monday.

An annual phenomenon in the stratosphere above Antarctica, the ozone hole is a dramatic thinning of the ozone layer that's typically boosted in size by colder temperatures.

This is the third time in 40 years that weather systems have caused warm temperatures that limit ozone depletion, according to scientists from NASA and the National Oceanic and Atmospheric Administration (NOAA). Similar weather patterns in the Antarctic stratosphere in September 1988 and 2002 also produced unusually small ozone holes.

“It’s important to recognize that what we’re seeing this year is due to warmer stratospheric temperatures,” said Paul Newman, chief scientist for Earth sciences at NASA's Goddard Space Flight Center, in a statement. “It’s not a sign that atmospheric ozone is suddenly on a fast track to recovery.”

In addition, there is no identified connection between these weather patterns and climate change, NOAA said.

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The ozone layer is important because it acts like a sunscreen, blocking potentially harmful ultraviolet energy from reaching our planet's surface. Without it, humans and animals can experience increased rates of skin cancer and other ailments such as cataracts.

The naturally occurring ozone high up in the atmosphere is the "good" ozone and is in contrast to the "bad" ozone near the surface, which is man-made pollution that can cause respiratory problems.

The annual ozone hole reached its peak size of 6.3 million square miles on Sept. 8 and then shrank to less than 3.9 million square miles during the remainder of September and October.

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In years with normal weather conditions, the ozone hole typically grows to a maximum of about 8 million square miles.

Scientists first discovered the dramatic thinning in Earth's protective ozone layer and the ozone hole in the 1970s. They determined the production of chlorofluorocarbons (CFCs) used in refrigerators and aerosol sprays caused the problem.

In the late 1980s, 196 countries signed the Montreal Protocol, a treaty that limited the production of CFCs around the world. Businesses soon came up with safer alternatives for spray cans and refrigerators.

Scientists expect the ozone hole to shrink to the size it was in 1980 by about 2070 as ozone-depleting chemicals banned by the Montreal Protocol but still in the atmosphere continue to decline.