Study finds a new ozone hole over Tropics

Context

According to a recent study,a new ozone hole has been detected over the tropics, at latitudes of 30 degrees South to 30 degrees North.

What has been found?

• The ozone hole is located at altitudes of 10-25 km over the tropics.
• This hole is about seven times larger than Antarctica.
• It also appears across all seasons, unlike that of Antarctica, which is visible only in the spring.
• The hole has become significant since the 1980s. But it was not discovered until this study.
  

What is ozone?

• Ozone is a molecule containing three oxygen atoms. It is blue in color and has a strong odor.
• Normal oxygen, which we breathe, has two oxygen atoms and is colorless and odorless.
  
• The Ozone Layer was discovered by the French physicists Charles Fabry and Henri Buisson in 1913.
• Chemically, ozone is very active; it reacts readily with a great many other substances.

• Near the Earth’s surface, those reactions cause rubber to crack, hurt plant life, and damage people’s lung tissues.

• But ozone also absorbs harmful components of sunlight, known as “ultraviolet B”, or “UV-B”
  
  

What is an ozone hole?

• During the Southern Hemisphere spring, chemical reactions involving chlorine and bromine cause ozone in the southern polar region to be destroyed rapidly and severely.
• This depleted region is known as the “ozone hole”.
• An ozone hole is an area where ozone levels drop below the historical threshold of 220 Dobson Units (DU is the measure of ozone concentrations).

Some Initiatives for Tackling Ozone Layer Depletion

• Vienna Convention for the Protection of the Ozone Layer-The scientific confirmation of the depletion of the ozone layer prompted the international community to establish a mechanism for cooperation to take action to protect the ozone layer.
• This was formalized in the Vienna Convention for the Protection of the Ozone Layer, which was adopted and signed by 28 countries, on 22 March 1985.
• In September 1987, this led to the drafting of The Montreal Protocol on Substances that Deplete the Ozone Layer.
• Montreal Protocol- The 1987 Montreal Protocol on Substances that deplete the Ozone Layer and its succeeding amendments were subsequently negotiated to control the consumption and production ofanthropogenic (ODSs) and some hydrofluorocarbons (HFCs).
• This phase-out plan includes both the production and consumption of ozone-depleting substances.
• On September 16, 1987, the United Nations and 45 other countries signed the Montreal Protocol, on substances that deplete the Ozone layer.
• India became Party to the Montreal Protocol on substances that deplete the Ozone layer on19thJune 1992.
• Kigali Amendment –The adoption of the 2016 Kigali Amendment to the Montreal Protocol will phase down the production and consumption of some HFCs and avoid much of the projected global increase and associated climate change.