Many countries are phasing out the use of ozone-destroying chemicals called CFCs to give the ozone hole a chance to heal itself. But one listener wonders whether it’s possible to take more direct measures.
Can we make a 'hole' lotta ozone? I'm Bob Hirshon and this is Science Update.
Today's Why Is It? Question came to us by e-mail from Lance Van Loenen, who has an idea about how to plug up the hole in the earth's ozone layer. He wants to know why we can't just make ozone down here, fly it up to the stratosphere, and release it.
Well, Lance, we talked to Bryan Johnson, an atmospheric chemist at the Climate Monitoring and Diagnostics Laboratory in Boulder, Colorado. He says your idea would require carrying a lot of replacement ozone more than eight miles up.
It really represents quite a massive amount of ozone. It's probably around 50 to 60 million tons. So when you figure out how much energy that would take to produce that much ozone, and to lift it that high in the atmosphere, it just wouldn't be feasible to do that.
And Johnson says making the ozone up there wouldn't work either. You'd still have to transport massive amounts of the chemicals needed to generate the ozone. So what can we do to patch the hole?...
The best way is just to continue to cut back on CFC production, which we've done very well on, and then let the atmosphere kind of heal itself.
If you've got a science question, call us at 1-800-WHY-ISIT. If we use it on the show you'll get a free Science Update mug. For the American Association for the Advancement of Science, I'm Bob Hirshon.
Making Sense of the Research
While we breathe the two-atom form of oxygen to live, the three-atom form, called ozone (O3), is toxic to us. Most of the Earth's ozone is in the upper atmosphere, 9-30 miles overhead. This layer of ozone protects Earth's living organisms by absorbing harmful ultraviolet radiation. For several months each year, much of the protective layer of stratospheric ozone above Antarctica disappears, creating what is popularly known as the ozone hole. With less ozone in the atmosphere, more ultraviolet radiation strikes Earth. This harmful radiation can cause skin cancer, injure eyes, harm the immune system, and upset the balance of an entire ecosystem.
Researchers have determined that chlorofluorocarbons (CFCs) have contributed to the depletion of ozone. CFCs are the human-made chemicals widely used in spray cans, foam packaging, and refrigeration materials. Chemically inert, CFCs accumulate in the atmosphere over time until they eventually drift to the upper atmosphere, where they encounter high energy UV radiation. The powerful UV rays break up CFC molecules, releasing chlorine atoms that destroy ozone.
Many countries have agreed to phase out the use of these ozone-destroying chemicals, thus giving the hole a chance to heal itself.
Now try to answer the following questions:
- Over which continent is the largest hole in the ozone layer located?
- Why are scientists and the general public concerned with the hole in the ozone layer?
- How many miles up would ozone need to be carried before it reached the stratosphere?
- How much ozone would be needed to fill the hole in the ozone layer?
- Is it feasible to make the ozone up there and then release it? Why or why not?
- What can we do to patch up the hole?
The EPA has great resources on ozone layer depletion, with sections on what we can each do to reduce the release of CFC's. You could explore Ozone Depletion or the cartoon entitled, On the Trail of the Missing Ozone.
Visit The Ozone Depletion Phenomenon from the Beyond Discovery website. This in-depth article provides a detailed explanation of the causes and impacts of ozone depletion.
6-12 | Audio
2014 Science Breakthrough of the Year: Rosetta Spacecraft
6-12 | Audio
6-12 | Audio