How fast is the ozone depleting

Environmental Protection Agency, eradicating ozone much more quickly than it can be replaced. The "hole" is actually an area of the stratosphere with extremely low concentrations of ozone that reoccurs every year at the beginning of the Southern Hemisphere spring August to October.

Spring brings sunlight, which releases chlorine into the stratospheric clouds. Recognition of the harmful effects of CFCs and other ozone-depleting substances led to the Montreal Protocol on Substances That Deplete the Ozone Layer in , a landmark agreement to phase out those substances that has been ratified by all UN member countries.

Without the pact, the U. More than 30 years after the Montreal Protocol, NASA scientists documented the first direct proof that Antarctic ozone is recovering because of the CFC phase-down: Ozone depletion in the region has declined 20 percent since And at the end of , the United Nations confirmed in a scientific assessment that the ozone layer is recovering, projecting that it would heal completely in the non-polar Northern Hemisphere by the s, followed by the Southern Hemisphere in the s and polar regions by A study in early found that ozone in the lower stratosphere unexpectedly and inexplicably has dropped since , while another pointed to possible ongoing violations of the Montreal pact.

The world is not yet in the clear when it comes to harmful gases from coolants. Some hydrochlorofluorocarbons HCFCs , transitional substitutes that are less damaging but still harmful to ozone, are still in use. Developing countries need funding from the Montreal Protocol's Multilateral Fund to eliminate the most widely used of these, the refrigerant R The next generation of coolants, hydrofluorocarbons HFCs , do not deplete ozone, but they are powerful greenhouse gases that trap heat, contributing to climate change.

Though HFCs represent a small fraction of emissions compared with carbon dioxide and other greenhouse gases , their planet-warming effect prompted an addition to the Montreal Protocol, the Kigali Amendment , in The amendment, which came into force in January , aims to slash the use of HFCs by more than 80 percent over the next three decades.

In the meantime, companies and scientists are working on climate-friendly alternatives, including new coolants and technologies that reduce or eliminate dependence on chemicals.

All rights reserved. The ozone layer reduces how much radiation makes it to the surface of the Earth. Without it, sunshine would be significantly deadlier to life on the planet. The primary culprit for its thinning, researchers discovered, was CFCs, a chemical compound that was present in everything from aerosol cans to refrigerators to solvents.

As CFCs degrade in the upper atmosphere, they can break down ozone. But the world responded. With consumer boycotts, political action, a major international treaty called the Montreal Protocol, and a huge investment in new technologies to replace CFCs in all their commercial and industrial uses, new CFC production was brought effectively to a halt over the s and early s. It took a while to phase out existing devices that used CFCs, but CFC emissions have been steadily falling since the protocol went into effect.

There is still much to be done and some new problems to contend with, but measurements from the present day make it clear that the process of healing the ozone layer is well underway. Ozone is a molecule made up of three oxygen atoms. The oxygen we breathe is made up of just two.

UV-B radiation is what causes sunburns, and in high concentrations it causes more problems than that. It can lead to many kinds of cancer by damaging our DNA; most plants and animals also suffer when growing in a high-UV-radiation environment. In the s, researchers noticed that the ozone layer had started thinning, especially around the poles. By the time the thinning of the ozone layer was measured, researchers Mario Molina and Sherry Rowland had already established the probable cause: CFCs.

CFCs were everywhere, and as far as everyone knew, they were the perfect chemical: nonreactive, cheap, and highly effective in a wide variety of manufacturing applications. Molina and Rowland realized that that assumption was wrong. The problem was that CFCs break down in the upper atmosphere.

And the chlorine in CFCs was actually reactive, binding with ozone to make oxygen and chlorine monoxide. Many researchers believed that ozone depletion would be a problem only on a time scale of centuries. There were some early worrying measurements that were dismissed as flukes. What the measurements in the Antarctic taken a decade later showed definitively is that it was happening much, much faster than that.

This continues until the stratospheric clouds disappear due to warming of the south polar atmosphere as summer approaches. By summertime, stratospheric air from lower latitudes is able to penetrate the polar latitudes, and thereby replenish the ozone layer above Antarctica. Hence, there is a seasonal cycle to the ozone hole over Antarctica with the lowest ozone levels recorded in late September and early October.

The ozone layer protects life from harmful UV-B radiation which can cause cancer and stunt the growth of plants. As UV radiation can penetrate into the surface of the ocean, marine organisms especially phytoplankton can also be damaged.

If there was no ozone layer at all, photosynthesis by plants would be impaired and ecosystems could not function as they do today — so it is clearly in our interest to make sure we do not damage the ozone layer. In an historic international agreement was signed the Montreal Protocol which came into force in and set deadlines for reducing and eliminating the production and use of ozone depleting substances.

It also promotes research and development into finding ozone safe substitute chemicals for the uses to which CFCs, etc. It has since been ratified by countries, has been revised several times, and has been described as one of the most successful international treaties.

Through its various mechanisms, the treaty has brought down worldwide emissions of CFCs and other ozone depleting chemicals sharply. However, due to the long residence time of many of these gases in the atmosphere for example CFC resides in the atmosphere for approximately years , the ozone layer will not fully recover until around Use the text above, and information from any of the links listed, to write your own summary of the ozone hole.

Address the following questions in your summary document:. Suggest some reasons why annual CFC emission is not the only factor affecting October ozone levels. Using the information in both this section and Climate change: past and future , as well as any of the suggested links, write an essay answering this question: Why does tackling the problem of global warming present a bigger challenge to the international community than the problem of the ozone hole?

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Which view of the future? You decide! Reporting on the future How is Antarctica governed? The Antarctic Treaty All agreed? Looking forward, the agency has called for wholehearted support of the Kigali Amendment to the Montreal Protocol, which entered into force on 1 January of this year. The agreement targets the phasing of hydrofluorocarbons HFCs , climate-warming gases, which could avoid up to 0. Levels of heat-trapping greenhouse gases in the atmosphere have reached another new record high, according to a report issued on Thursday by the United Nations weather agency, which reveals that there is no sign of reversal of this trend, responsible for climate change, sea level rise, ocean acidification and extreme weather.

The findings of a new UN-backed report , released on Monday, showing the ongoing healing of the ozone layer, are being hailed as a demonstration of what global agreements can achieve, and an inspiration for more ambitious climate action to halt a catastrophic rise in world temperatures.

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