Introduction
Ozone is a gas that exists both in the Earth's upper atmosphere and at ground level. Depending on where it is in the atmosphere, ozone can be "good" or "bad" for ones health and the environment.
Ozone can be found in two layers of the atmosphere i.e Ground level or "bad" ozone that is present in Troposphere and one that is found in the stratosphere which is called "good" ozone, the layer that shields Earth's life from the sun's harmful ultraviolet (UV) rays.
Tropical hole
Scientists revealed a large, comparable in depth to that of the well-known springtime Antarctic hole, but roughly seven times greater in area.
The obtained findings are consistent with the cosmic-ray-driven electron reaction (CRE) model and strongly suggest that the same physical mechanism is responsible for both the Antarctic and tropical ozone holes. About half of the world's population lives in the tropics, which cover half of the planet's surface area. The existence of the ozone hole in the tropics may cause worldwide concern.
Concerns
Threat to Human and Animal health
The depletion of the ozone layer can result in an increase in ground-level ultraviolet radiation, which can increase the risk of skin cancer and cataracts in humans, as well as weaken human immune systems, reduce agricultural productivity, and negatively impact sensitive aquatic organisms and ecosystems. Animals are equally susceptible,on being exposed to UV light for a lengthy period of time can develop skin cancer and cataract too.
Productivity can Decline- Food Insecurity
Many crops, including barley, wheat, corn, oats, rice, tomatoes, and cauliflower, are susceptible to high UV light, which reduces their growth rate, blooming, and photosynthesis.
Endanger Marine Ecosystem
When exposed to intense UV light, the growth of certain marine phytoplanktons is inhibited. As a result of the appearance of planktons at a higher level of the food chain, the entire marine environment is affected. In addition, the fish have severe reproductive abnormalities, which reduces their population.
On exposure to UV light, man-made compounds such as plastics, wood, textiles, and rubber undergo significant degradation.
Agreements So Far
Vienna Convention
By 1985, the world had made significant advances in scientific understanding of ozone depletion and its effects on human health and the environment. In response, the Vienna Convention for the Protection of the Ozone Layer was established.
The Vienna Convention was the first of its kind to be signed by every country involved, going into effect in 1988 and achieving universal ratification in 2009.
This agreement is a framework convention that lays out principles that many parties have agreed upon. However, it does not require countries to take control measures to protect the ozone layer.
This was however later realised in the form of the Montreal Protocol.
Montreal Protocol
The Montreal Protocol on Substances that Deplete the Ozone Layer is a global agreement that aims to protect the Earth's ozone layer by phasing out depleting chemicals. These chemicals are called HFCs or hydrochlorofluorocarbons.
The production and consumption of ozone-depleting substances are both included in this phase-out plan. This historic agreement was signed in 1987 and went into effect in 1989.
The Montreal Protocol was never intended to be a tool for combating climate change, but it has become one with the Kigali Amendment.
Kigali Agreement - Amendment to Montreal Protocol ( phase out HFC’s)
The Kigali Agreement, like the Montreal Protocol, has different targets for high- and low-income countries. Countries such as the United States must meet this goal by 2036, while India has until 2047 and China has until 2045.
The Kigali Amendment's contribution to mitigating global warming is especially significant in light of the Paris Agreement, another critical climate treaty.
The Paris Agreement, signed in 2015, is a legally binding policy that requires countries to reduce greenhouse gas emissions in order to slow global warming. The agreement aims to keep global temperatures "well below" a pre-determined threshold — 2°C above pre-industrial levels — in order to avoid extreme weather events and climate change.