Three decades of the Montreal Protocol – what was the impact?

16 September marked the International Day for the Preservation of the Ozone Layer and the 30th anniversary of the Montreal Protocol, which first banned ozone-depleting substances (ODSs) like CFCs. What difference has this made in the past 30 years?

From lower food prices to reduced emissions, the ban on ozone-depleting substances has guided the world’s response to climate change and human health, reports

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CFCs contain the molecules chlorine and bromine, which in 1986 US researcher Susan Solomon discovered were destroying the atmosphere.

The discovery led to a global ban under the Montreal Protocol in 1987. Since then the situation has improved vastly. Researchers at MIT last year published a study comparing the ‘thinning’ between 2000 and last year. They found that the hole above Antarctica is now around four million km2– roughly the size of India but smaller than before and is continuing to shrink.

Huge emission reduction

The ban has not just led to the healing of the ozone layer: a recent study confirms that the international treaty has helped to reduce greenhouse gas (GHG) emissions in the United States. CFCs were not just ODSs but also highly pollutant gases with global warming potential 10 000 times greater than CO2, according to researchers Hu et al. in their study entitled ‘Considerable contribution of the Montreal Protocol to declining greenhouse gas emissions from the United States’.

The study shows that the reduction in ODSs from 2008 to 2014 eliminated 170mt of CO2-equivalent emissions each year and is roughly equivalent to 50% of the reduction in emissions of CO2 and other GHGs in the US in the same period.

"We were surprised by the size of the decline, especially compared with other greenhouse gases," says Lei Hu, a researcher with the Cooperative Institute for Research in Environmental Sciences (CIRES), working at the US National Oceanic and Atmospheric Administration (NOAA) and lead author of the new study.

Food prices lowered

Other research by the UK’s National Environment Research Council found that the reduction in ODSs has spared thousands of lives and led to lower food prices, leading to savings of £1.3-billion every year for the UK, thanks to the early implementation of the Montreal Protocol.

The research also pointed out that without the ODS ban under the Montreal Protocol, the cost of this delay would have resulted in 300 more skin cancer cases every year in the UK by 2030, costing the NHS around £550-million a year in today's money. Analysis by Deloitte estimates it avoided losses in farm production worth up to £740-million a year.

“The Montreal Protocol is a remarkable agreement which we are seeing the effects of now,” says Jonathan Shanklin from NERC. “Signs of recovery of the ozone hole are becoming evident, which will have huge benefits to society with fewer cases of UV-related problems. It demonstrates that when policy and science work together it can result in effective action.”

Kigali Amendment

The Kigali Amendment to the Montreal Protocol, agreed last October in the Rwandan capital, is another boon to climate efforts in the US, UK and around the world. It will phase down hydrofluorocarbons (HFCs), which replaced CFCs used in the HVAC&R sector.

HFCs are also potent greenhouse gases, and their increased use is offsetting some of the climate benefits of the Montreal Protocol, according to Stephen Montzka, a researcher at NOAA and co-author of the new Hu et al study on US greenhouse gas emissions.

The Montreal Protocol, “Shows what can be achieved by concerted and thoughtful international effort," says Scott Lehman of the Institute of Arctic and Alpine Research at the University of Colorado, Boulder and co-author of the US greenhouse study.

30 years of healing the ozone layer - how it all happened




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