Healing the Ozone Layer: Chemist Says Treaty Is Working

The Montreal Protocol, enacted in 1987, put controls on use of aerosol CFCs.

Aerosol cans no longer contain ozone-depleting substances called CFCs, or chlorofluorocarbons.

Photograph by Mark Thiessen, National Geographic

Johnna Rizzo

Published April 16, 2013

“The Montreal Protocol is working,” says chemist Mario Molina, who shared the Nobel Prize for his work on the effects of chlorofluorocarbons (CFCs). “CFCs are a global environmental problem that is being solved by society.”

The international treaty, which opened for signature in 1987, created controls on the use of CFCs, gases used as coolants in refrigerators and to propel aerosols like hair spray out of cans. The problem was that CFCs spread out in the stratosphere, where they led to a hole in the ozone layer.

When Molina started studying CFCs in the 1970s and discovered their role in ozone depletion, each U.S. household averaged 30 to 40 spray cans. Since the late ’90s, CFC production has all but stopped, making modern spray cans ozone safe.

The ozone layer itself? Though scientists say it will take until beyond 2050 to return to pre-1980s levels of CFCs—they take about a hundred years to decompose—the amounts in the atmosphere are steadily decreasing. (See chart below.)

Chart by NGM Art. Source: David W. Fahey, NOAA Earth System Research Laboratory

2 comments

Newest | Oldest

Rachel Maines

I, and a few others I know who have asthma have actually ended up in the hospital thanks to this protocol. The propellants we need were in asthma emergency inhalers. Without the propellants, the inhalers are not as effective... (Usually requiring 5-8 sprays, where with CFC propellant, we'd only need one.)
I had read somewhere that earth naturally has a certain CFC level, and that even if all the asthmatics used their inhalers at the same time, it still would be a tiny fraction of the natural level.
I can see the good that the Montreal Protocol is doing, but I just wish they could let medical necessity allow CFC use in such tiny doses.

Mihajlo Filipovic

Good news, but it will take more than that to convince me of the actual bettering. One way would be to ban propellant usage, since it takes the same (minimal) effort to press a mechanical spray pump and to activate the pressurized vessel... so why do we need propellants at all, especially for the more-damage-than-worth purposes it's been mainly used for?

As with all human solutions to ecological problems, this one takes some radical changes in approach as well, but there is obviously no authority to do it. So it looks like our laziness and commercial inertia are stronger than gravity...

News Video

See All News Video »

Latest News

Celebrating 125 Years

Explorer Moment: Azorean Whalers

With Força, Gemina Garland-Lewis learns what it takes to be an Azorean whaler.
From the Stacks: Meow Mix, 1938

Not all the animals National Geographic has covered have been wild ones.