Carbon monoxide is considered a pollutant and ‘indirect’ greenhouse gas, containing toxic properties that contribute to the lifetime of methane in the atmosphere.
A timeline of carbon monoxide concentrations over Antarctica developed by a team of international researchers led by the French National Centre for Scientific Research and Australia's national science agency CSIRO, shows carbon monoxide levels rapidly rising from the 1940s, exceeding their centuries-long average. However, in 1985, the rapid rise abruptly stops.
CSIRO atmospheric scientist David Etheridge noted that this incident was aligned with a significant change in the automotive industry, namely the introduction of the catalytic converter.
"Catalytic converters were introduced quite rapidly within about a decade, largely across most of the global fleet of petrol engines," Dr Etheridge told ABC news.
Interestingly, Dr Etheridge also expressed that the rapid reduction in emissions was in fact despite the increase in number of vehicles being driven around the world for the past three decades.
The catalytic converter
A catalytic converter is a device installed in the exhaust system of a vehicle to convert toxic gasses like carbon monoxide, into less-toxic pollutants.
First installed in Californian cars and later adopted worldwide through the 1970s and 1980s, catalytic converters help in mitigating the emissions of smog and other pollutants into the atmosphere.
In Australia, the shift took place in 1986, when stricter emission control laws targeting substances like hydrocarbons, carbon monoxide, and nitrous oxide were introduced for newly manufactured cars.
According to former Holden project engineer Warwick Bryce, the primary goal was to clean the atmosphere up.
"You had soot and deposits and all that sort of stuff making buildings dirty and grey, and brown clouds over your sky, so it was really the visual pollution and the harmful effects of unclean air,” Mr Bryce said.
Mr Bryce worked in engine design and development. In a lecture in 1980, he said that catalytic converters and unleaded fuel were among the best technology options available if stricter emissions controls were to be introduced in Australia.
“In one fell swoop catalytic converter technology, used in conjunction with electronic fuel injection, reduced emissions of both hydrocarbons and carbon monoxide coming out the tailpipe by 95 per cent, and for nitrous oxide by 90 per cent of what the engine was producing, while at the same time fuel consumption was improved,” Bryce said.
A positive outcome for the climate
While it was expected that catalytic converters would lessen carbon monoxide levels at a local level, Dr Etheridge highlighted the unforeseen changes that also extended to Antarctica, benefitting the climate across the entire hemisphere.
A subsequent study on its impact towards the climate would be carried out to identify what causes the rising toxic gas levels to stop, and whether this trend would persist in the future.
Another good example of international action to address environmental issues is the Montreal Protocol for the Protection of the Ozone Layer. With the world currently facing a triple planetary crisis of climate change, biodiversity loss and pollution, stories of intergovernmental collaboration like this represent hope for those seeking swifter action.
Prior to the United Nations Climate Change Conference in Dubai (COP28), Dr Etheridge said he hoped it would serve as a wake-up call for policymakers and the public, that there was a possibility to reduce climate change when science, government, and industry join hands in action.
"I think it's encouraging to see it's not all bad news, but the task ahead is enormous, and we've got to see some action very soon." said Dr Etheridge.
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