Earlier this year, however, a study reported that ozone concentrations in the lower level of the stratosphere had been falling since the late s — even though the Montreal Protocola global treaty to phase out ozone-depleting chemicals, had been in effect since This raised questions about whether and how human activities could still be damaging the ozone layer. The overall picture is clear: The Montreal Protocol reduced use of ozone-depleting chemicals and will lead to healing of the ozone layer.
To understand, you have to go back about years. InAntoine Lavoisier proved that oxygen was a chemical element, and it took its place as number eight on the periodic table. Passing electricity through oxygen produced a strange, slightly pungent smell. A pair of French scientists named Charles Fabry and Henri Buisson used an interferometer to make the most accurate measurements ever of ozone in the atmosphere in Because it blocks some radiation from reaching Earth's surface, ozone provides critical protection from the sun's scorching rays.
Even as researchers began to study ozone levels over time, they started to think about whether it was capable of being depleted.
By the s, they were asking how emissions from things like supersonic aircraft and the space shuttle, which emitted exhaust directly into the stratospheremight affect the gases at that altitude. But what they found shocked even scientists who were convinced that CFCs deplete ozone.
Richard Farman, an atmospheric scientist who had been collecting data in Antarctica annually for decades, thought his instruments were broken when they began to show drastic drops in ozone over the continent. The ozone layer had been damaged more than scientists could have imagined before Farman discovered the hole.
As word of the ozone hole leaked through the media, it became nothing short of a worldwide sensation. Rumors of blind sheep —the increased radiation was thought to cause cataracts—and increased skin cancer stoked public fears.
Fueled in part by fears of the ozone hole worsening, 24 nations signed the Montreal Protocol limiting the use of CFCs in These days, scientists understand a lot more about the ozone hole. As weather cools during Antarctic winter, the hole gradually recovers until next year.
Each year during ozone hole season, scientists from around the world track the depletion of the ozone above Antarctica using balloons, satellites and computer models. They have found that the ozone hole is actually getting smaller: Scientists estimate that if the Montreal Protocol had never been implemented, the hole would have grown by 40 percent by Instead, the hole is expected to completely heal by Since the hole opens and closes and is subject to annual variances, air flow patterns and other atmospheric dynamics, it can be hard to keep in the public consciousness.
Bryan Johnson is a research chemist at the National Oceanic and Atmospheric Administration who helps monitor the ozone hole from year to year. He says public concern about the environment has shifted away from the hole to the ways in which carbon dioxide affects the environment.an atmospheric layer at heights of about 20 to 30 miles (32 to 48 kilometers) that is normally characterized by high ozone content which blocks most solar ultraviolet radiation from entry into .
The study, published Thursday in Geophysical Research Letters, reveals that a decline in ozone-depleting chemicals has resulted in 20 percent less depletion since Specifically chlorine.
The Ozone Hole Was Super Scary, So What Happened To It?
When the ozone hole was discovered, it became a worldwide sensation. Thirty years later, what’s become of it? What is ozone and why is it important to our survival?
This lesson plan uses a fact-based video lesson to highlight primary facts and an activity. Earth's ozone layer shields us from harmful ultraviolet radiation.
Nations have been working to reduce ozone-depleting chemicals since the s, but recent studies show that there is still work. By Alecia M. Spooner. Air pollution has the ability to affect the earth’s entire ecosystem, as environmental scientists realized when they found direct links between ozone layer destruction and manmade pollutants called CFCs.