How much has the ozone layer depleted since the 1970s?

How much has the ozone layer depleted since the 1970s?

Ozone depletion consists of two related events observed since the late 1970s: a steady lowering of about four percent in the total amount of ozone in Earth’s atmosphere (the ozone layer), and a much larger springtime decrease in stratospheric ozone around Earth’s polar regions.

How much did the ozone layer decrease between 1979 and 1993?

From 1979 to 1993, the average amount of ozone in the stratosphere has decreased by about 5%. A graph showing ozone amounts decreasing by 5% from 1979 to 1993.”

What happened to the ozone layer in 1970?

Unfortunately,human-produced chemicals in our atmosphere—such as chlorofluorocarbons (CFCs), used for many years as refrigerants and in aerosol spray cans—have depleted the Earth’s ozone layer. Scientists first recognized the potential for harmful effects of CFCs on ozone in the early 1970s.

How big was the ozone hole in 1970?

The ozone hole reached its peak size at about 9.6 million square miles (or 24.8 million square kilometers), roughly three times the area of the continental United States, on September 20. Observations revealed the nearly complete elimination of ozone in a four-mile-high column of the stratosphere over the South Pole.

How much percent of the ozone layer is left?

Ozone levels have dropped by a worldwide average of about 4 percent since the late 1970s. For approximately 5 percent of the Earth’s surface, around the north and south poles, much larger seasonal declines have been seen, and are described as “ozone holes”.

What effect has the Montreal Protocol had on the stratospheric ozone layer?

The Montreal Protocol has been successful in reducing ozone-depleting substances and reactive chlorine and bromine in the stratosphere. As a result, the ozone layer is showing the first signs of recovery.

How did the Montreal Protocol decreased ozone depletion?

The Montreal Protocol, finalized in 1987, is a global agreement to protect the stratospheric ozone layer by phasing out the production and consumption of ozone-depleting substances (ODS).

How is the ozone destroyed in the stratosphere?

Ozone Depletion. When chlorine and bromine atoms come into contact with ozone in the stratosphere, they destroy ozone molecules. One chlorine atom can destroy over 100,000 ozone molecules before it is removed from the stratosphere. Ozone can be destroyed more quickly than it is naturally created.

When did they start measuring ozone in the air?

By the middle of the 1870s, ozone was established as a potentially important component of the normal atmosphere. Several tests had been developed to measure the amount of ozone in the air. Debates raged over the accuracy of these measurements that used litmus-type papers.

When did the ozone ban come into effect?

The ban came into effect in 1989. Ozone levels stabilized by the mid-1990s and began to recover in the 2000s, as the shifting of the jet stream in the southern hemisphere towards the south pole has stopped and might even be reversing.

Why is the amount of ozone in the tropics so low?

In the Southern Hemisphere’s mid-latitudes, total ozone remained constant over that time period. There are no significant trends in the tropics, largely because halogen-containing compounds have not had time to break down and release chlorine and bromine atoms at tropical latitudes.