Lesser-known form of ozone heating Antarctic Ocean, research shows

New research led by UC Riverside has revealed a lower level of ozone is playing a major role in heating the Antarctic Ocean.

Ozone is a gas composed of three oxygen atoms and can be found in the stratosphere, filtering ultraviolet radiation from the sun. 

However, ozone that’s closer to ground level in the troposphere is a powerful greenhouse gas that is harmful to human health and the ecosystem. 

An international team of scientists explored climate model simulations with changes on ozone levels between 1955 and 2000 to learn more about the impact of this.

It was discovered that while both stratospheric and tropospheric ozone contributed to the warming of the Antarctic Ocean, the latter contributed more. 

Climate scientist and lead author of the new study, Wei Liu, said:  ‘People haven’t paid much attention in the past to tropospheric ozone in terms of ocean heat uptake. Based on our models, they should be.

‘Historically, about a third of the ocean’s warming is attributable to ozone. For this third, about 40% is from the stratosphere, and the rest is troposphere.’ 

Oceans are vital to beating the climate crisis, since they remove the majority of carbon and heat that enter the atmosphere when fossil fuels are burned. 

The Antarctic Ocean alone collects a third of all excess carbon in the atmosphere and 75% of excess heat, so it’s important we understand how heating can be controlled. 

Previous worries about a pollution-generated hole in the upper ozone layer led to a landmark environmental agreement – the Montreal Protocol. 

Made in the 1980’s by all 198 members of the United Nations, the regulation of chemicals generating the hole has led to some recovery of the ozone layer. 

Satellite images show low levels of stratospheric ozone over the Antarctic.  

Volatile organic compounds (VOCs) form the tropospheric ozone, from products such as pesticides and cars.

Nitrogen oxides and carbon monoxide from furnaces, gas stoves and car exhausts also contribute, but many of these products can be modified to produce less VOCs. 

Liu said: ‘Tropospheric ozone is an air pollutant. If we reduce our production of this, we get the dual benefits of less air pollution and most likely, less Southern Ocean warming as well.’

Photo by Henrique Setim