More protection: UN says Earth's ozone layer is healing

November 5, 2018 by Seth Borenstein
More protection: UN says Earth's ozone layer is healing
This combination of images made available by NASA shows areas of low ozone above Antarctica on September 2000, left, and September 2018. The purple and blue colors are where there is the least ozone, and the yellows and reds are where there is more ozone. A United Nations report released on Monday, Nov. 5, 2018 says Earth's protective ozone layer is finally healing after aerosol sprays and coolants ate away at it. (NASA via AP)

Earth's protective ozone layer is finally healing from damage caused by aerosol sprays and coolants, a new United Nations report said.

The ozone layer had been thinning since the late 1970s. Scientists raised the alarm and ozone-depleting chemicals were phased out worldwide.

As a result, the upper ozone layer above the Northern Hemisphere should be completely repaired in the 2030s and the gaping Antarctic ozone hole should disappear in the 2060s, according to a scientific assessment released Monday at a conference in Quito, Ecuador. The Southern Hemisphere lags a bit and its ozone layer should be healed by mid-century.

"It's really good news," said report co-chairman Paul Newman, chief Earth scientist at NASA's Goddard Space Flight Center. "If ozone-depleting substances had continued to increase, we would have seen huge effects. We stopped that."

High in the atmosphere, ozone shields Earth from ultraviolet rays that cause skin cancer, crop damage and other problems. Use of man-made chemicals called chlorofluorocarbons (CFCs), which release chlorine and bromine, began eating away at the ozone. In 1987, countries around the world agreed in the Montreal Protocol to phase out CFCs and businesses came up with replacements for spray cans and other uses.

At its worst in the late 1990s, about 10 percent of the upper ozone layer was depleted, said Newman. Since 2000, it has increased by about 1 to 3 percent per decade, the report said.

This year, the ozone hole over the South Pole peaked at nearly 9.6 million square miles (24.8 million square kilometers). That's about 16 percent smaller than the biggest hole recorded—11.4 million square miles (29.6 million square kilometers) in 2006.

The hole reaches its peak in September and October and disappears by late December until the next Southern Hemisphere spring, Newman said.

The ozone layer starts at about 6 miles (10 kilometers) above Earth and stretches for nearly 25 miles (40 kilometers); ozone is a colorless combination of three oxygen atoms.

If nothing had been done to stop the thinning, the world would have destroyed two-thirds of its ozone layer by 2065, Newman said.

But it's not a complete success yet, said University of Colorado's Brian Toon, who wasn't part of the report.

"We are only at a point where recovery may have started," Toon said, pointing to some ozone measurements that haven't increased yet.

Another problem is that new technology has found an increase in emissions of a banned CFC out of East Asia, the report noted.

On its own, the ozone hole has slightly shielded Antarctica from the much larger effects of global warming—it has heated up but not as much as it likely would without ozone depletion, said Ross Salawitch, a University of Maryland atmospheric scientist who co-authored the report.

So a healed ozone layer will worsen man-made climate change there a bit, Newman said.

Scientists don't know how much a healed ozone hole will further warm Antarctica, but they do know the immediate effects of ozone depletion on the world and human health, so "it would be incredibly irresponsible not to do this," Salawitch said.

And the replacements now being used to cool cars and refrigerators need to be replaced themselves with chemicals that don't worsen global warming, Newman said. An amendment to the Montreal Protocol that goes into effect next year would cut use of some of those gases.

"I don't think we can do a victory lap until 2060," Newman said. "That will be for our grandchildren to do."

Explore further: Ozone hole modest despite optimum conditions for ozone depletion

Related Stories

New kid on the block picks up relay for ozone

September 17, 2018

For more than 20 years, changes in ozone over Antarctica have been carefully monitored by a succession of European satellites. This important long-term record is now being added to by the Copernicus Sentinel-5P mission, which ...

UN weather body: Antarctic ozone hole expands due to cold

October 29, 2015

The Antarctic ozone hole has swelled this month to one of its biggest sizes on record, U.N. and U.S. scientists say, insisting that the Earth-shielding ozone layer remains on track to long-term recovery but residents of the ...

Video: Earth's ozone layer

April 7, 2015

Several decades ago, chlorofluorocarbons (CFCs) were chemicals used in hairspray, deodorants, foam products, air conditioners and more. In 1974 chemists Sherwood Rowland and Mario Molina published a paper that indicated ...

Scientists say the ozone layer is recovering

September 10, 2014

Earth's protective ozone layer is beginning to recover, largely because of the phase-out since the 1980s of certain chemicals used in refrigerants and aerosol cans, a U.N. scientific panel reported Wednesday in a rare piece ...

2012 Antarctic ozone hole second smallest in 20 years

October 24, 2012

The average area covered by the Antarctic ozone hole this year was the second smallest in the last 20 years, according to data from NASA and National Oceanic and Atmospheric Administration (NOAA) satellites. Scientists attribute ...

Recommended for you

Physicists reveal why matter dominates universe

March 21, 2019

Physicists in the College of Arts and Sciences at Syracuse University have confirmed that matter and antimatter decay differently for elementary particles containing charmed quarks.

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

JamesG
not rated yet Nov 05, 2018
The UN is a fraud. Don't believe anything the say.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.