Does tropical ozone hole exist?

Does tropical ozone hole exist?

Subject: Environment

Section: Climate Change

Context: According to the recent study, ozone hole is located at altitudes of 10-25 km over the tropics

What is tropical ozone hole?

• A new ozone hole has been detected over the tropics, at latitudes of 30 degrees south to 30 degrees North
• The hole has become significant since the 1980s. But it was not discovered until this study
• The tropical ozone 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 tropical ozone hole, which makes up 50 per cent of Earth’s surface, could cause a global concern due to the risks associated with it
• It is likely to cause skin cancer, cataracts and other negative effects on the health and ecosystems in tropical regions
• The tropical stratosphere recorded a low temperature of 190-200 Kelvin (K). This explains the tropical ozone hole is constantly formed over the seasons

What is ozone?

• Ozone is a colorless gas. 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”
• High above the surface, above even the weather systems, a tenuous layer of ozone gas absorbs UV-B, protecting living things below

What is 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)

The Montreal Protocol

The Montreal Protocol on Substances that Deplete the Ozone Layer is the landmark multilateral environmental agreement that regulates the production and consumption of nearly 100 man-made chemicals referred to as ozone depleting substances (ODS).

Adopted on 15 September 1987, the Protocol is to date the only UN treaty ever that has been ratified every country on Earth – all 198 UN Member States

The Kigali Amendment

The Parties to the Montreal Protocol reached agreement at their on 15 October 2016 in Kigali, Rwanda to phase-down HFCs.