The ozone hole has reached its largest size since 2015 and scientists do not care

Last week, a hole in the ozone layer over Antarctica reached its largest size since 2015.

The ozone hole forms annually over Antarctica, and for the third year in a row, the hole has grown significantly.

The ozone hole covers an area of ​​almost 10 million square miles (26.4 million square kilometers) and is the largest since 2015.

Despite this significant increase, the scientists say overall the size of the hole is still on a downward trend.

“All the evidence is that ozone is improving,” Paul Newman, principal earth scientist at NASA’s Goddard Space Flight Center, told The Associated Press.

Ozone is made up of three oxygen atoms and makes up a very small part of our atmosphere but has a huge impact on our planet.

A blanket that covers the entire globe absorbs the sun’s most harmful ultraviolet rays, protecting life on Earth.

Ozone is formed in the stratosphere 9 to 18 miles (14.5 to 29 km) above the Earth’s surface.

It is formed when ultraviolet rays split ordinary oxygen molecules consisting of two oxygen atoms (molecular oxygen or dioxygen O2), then two floating oxygen atoms bind to an oxygen molecule, forming a molecule consisting of three oxygen atoms.

Scientists discovered a thin ozone layer over Antarctica in the early 1980s. While ozone naturally forms and breaks down in the stratosphere, anthropogenic pollution is destroying ozone faster than it can form. In particular, industries that use chlorine or bromine, such as refrigeration and air conditioning, destroy ozone at an alarmingly high rate.

In the stratosphere, chlorine molecules react with ozone to form one chlorine monoxide molecule (consisting of one chlorine molecule and one oxygen molecule) and one molecule of O2.

The chlorine monoxide molecule then dissociates and a chlorine atom is released, which reacts with more ozone.

According to the Environmental Protection Agency, one chlorine atom can destroy 100,000 ozone molecules before one chlorine molecule is removed from the atmosphere.

Substances such as chlorofluorocarbons, which are used in refrigeration and air conditioning, remain in the atmosphere for long periods of time, some for more than six months, meaning that chlorine and other chemicals in these substances can deplete the ozone layer.

According to NASA, the ozone hole was first discovered in the early 1980s and reached its maximum size in 2006.

And the cold stratosphere is exactly what chemicals like chlorine need to destroy the ozone layer. During the Antarctic winter, the atmosphere becomes cold enough for clouds to form.

The ice crystals that make up these clouds form a surface on which, for example, chlorine can react with ozone.

As spring approaches in September, the sun’s ultraviolet rays stimulate these reactions. When summer arrives, the stratosphere becomes hot enough for clouds to evaporate, removing the surface where chemical reactions take place that destroy the ozone layer.

Global conventions such as the Montreal Protocol, which governs the production and consumption of ozone-depleting substances, have helped close the ozone hole. While the ozone hole has grown in size this year, scientists generally agree that it is shrinking.

Earlier this year, the National Oceanic and Atmospheric Administration reported that ozone-depleting substances in the atmosphere had fallen by 50 percent since 1980. The report also notes that if this downward trend continues, the ozone layer could be fully restored by 2070.

This year’s ozone hole, which peaked on October 5, was the largest on record since 2015. But scientists don’t care, Newman told the Associated Press, “The general trend is getting better. it’s still a little cold.”

Source: Living Science