Big ozone holes headed for extinction

NARRATOR: Say goodbye to large ozone holes. A new study from NASA scientists suggests by the year 2040, the Antarctic ozone hole will be permanently smaller than the giant holes of today. Since the early 90s, observed hole sizes have been larger than 8 million square miles with exact sizes changing each year.

DR SUSAN STRAHAN, SENIOR RESEARCH SCIENTIST, NASA GODDARD SPACE FLIGHT CENTER: The ozone hole is a seasonal thinning of the ozone layer over Antarctica. The ozone hole size varies in part due to levels of ozone-depleting chemicals in the atmosphere. 

NARRATOR: Man-made chemicals that destroy ozone are transported from the equator to the poles. In the Southern Hemisphere, they are trapped by the winds of the polar vortex, a ring of fast-moving air that circles the South Pole. 

DR SUSAN STRAHAN: Although levels of these chemicals have been declining since the late 1990s due to the Montreal Protocol, they will remain in the atmosphere for years, affecting ozone levels well into the century.

NARRATOR: High in the atmosphere, the chemicals react with sheets of iridescent ice clouds which trigger the destruction of ozone. In years with warm temperatures, fewer ice clouds form, resulting in holes that are smaller. In years with cold temperatures, more ice clouds form, resulting in holes that are larger. But in order to understand how hole sizes will change in the future, scientists needed a more accurate picture of levels of man-made chemicals in the atmosphere. Using NASA’s Aura satellite, scientists determined how chemical levels in the ozone hole varied each year.

DR SUSAN STRAHAN: With this new information, we can look into the future and say with confidence that ozone holes will be consistently smaller than 8 million square miles by 2040. And that will really be a milestone that we’re finally past the era of big ozone holes.