Does a tropical ozone hole exist? Experts are divided

Source: The post is based on the article “Does a tropical ozone hole exist? Experts are divided” published in Down To Earth on 15th July 2022

What is the News?

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 is Ozone Hole?

Researchers used a different definition of the ozone hole in this study. The study defined it as an area with ozone loss larger than 25% compared to the normal ozone value.

According to NASA, 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).

Ozone Hole over Tropics

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

This ozone hole is located at altitudes of 10-25 km over the tropics. It is about seven times larger than Antarctica.

It also appears across all seasons, unlike that of Antarctica, which is visible only in the spring.

Risks Involved: The Tropical ozone hole, which makes up 50% 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.

What are the criticisms against this study?

Firstly, the mechanism of ozone loss proposed by this study has been discredited.

Secondly, this study used the 1960s dataset on ozone changes. The trouble is that there were very few observations in the 1960s and most were based on model reconstructions which were poor.