In the fall months of September and October 2019, an unusual event occurred in the skies above our planet’s southernmost region. The size of the ozone hole over Antarctica was reported to be the smallest since its discovery in 1982. However, this measured shrinkage does not necessarily herald a vigorous recovery of atmospheric ozone. Instead, it reflects the ambient effects of temporary warming in the Antarctic region.
Understanding the 2019 Shrinkage of the Ozone Hole
The abnormal reduction in the size of the 2019 Antarctic ozone hole is largely attributable to unique weather patterns prevalent during that year over Antarctica. These patterns led to an increase in temperatures, consequently affecting the formation and longevity of polar stratospheric clouds (PSCs).
PSCs play a crucial role in the depletion of the ozone layer by acting as a catalyst in the release of chlorine and bromine molecules, which then proceed to break down the ozone. With fewer PSCs forming due to the warmer temperatures, and their inability to persist for extended periods, the ozone-depletion process was significantly restrained.
Ozone: Its Dual Nature and Impact on Life
Ozone, a molecule consisting of three atoms of oxygen, is present both in the Earth’s upper atmosphere (stratosphere) and at ground level (troposphere). Depending on its location, it can either be beneficial or harmful.
“Good” Ozone and Its Role
In the Earth’s upper atmosphere, ozone naturally occurs and forms a protective layer that guards us from the sun’s destructive ultraviolet rays. This “good” ozone can be destroyed by ozone-depleting gases such as chlorofluorocarbons (CFCs), HCFCs, and halons. The depletion of this protective shield results in the infamous ‘ozone hole’. India, amongst others, has taken a keen interest in combating this issue through the adoption of the Kigali Amendment to the Montreal Protocol, aiming to phase down the use of hydrofluorocarbons.
“Bad” Ozone: A Detrimental Byproduct
At ground level, or in the lower atmosphere, ozone formation is a result of a chemical reaction between pollutants emitted by multiple sources such as cars, power plants, industrial boilers, refineries, and chemical plants, especially in the presence of sunlight. This closer-to-the-ground ozone is a harmful air pollutant.
| Ozone Formed in | Description | Impact |
|---|---|---|
| Upper Atmosphere | Occurs naturally, forms a protective layer against the sun’s UV rays | Beneficial, but can be broken down by certain gases causing the ‘ozone hole’ |
| Lower Atmosphere | Formed by chemical reactions between multiple pollutants, often in the presence of sunlight | Harmful, acts as an air pollutant |
The Unconventional Factors Behind The 2019 Antarctic Ozone Hole Shrinkage
While it is indeed a relief to see the shrinking of the ozone hole in the year 2019, it is essential to note that this occurrence was due to a temporary fluctuation in weather patterns and temperature rise in the Antarctic region, and not a result of long-term atmospheric recovery. Therefore, constant vigilance and continued efforts are necessary to ensure the longevity and health of our planet’s protective ozone layer.