Top ozone experts from around the world highlighted the need for increased research and observations to inform policy on ozone and climate at a meeting sponsored by UN Environment and the World Meteorological Organization in Geneva, 28 – 30 March.
The 10th Ozone Research Managers (ORM) meeting concluded that integrated earth science observation systems are essential to ensure that action to protect the ozone layer also benefits the climate, given the complex and evolving interaction between the ozone layer and the climate system.
This key ozone/climate coupling has been captured in the overarching finding of the Ozone Research Managers that states: Understanding the complex coupling of ozone, atmospheric chemistry, transport and climate changes remains a high priority and the need for further research and systematic monitoring in this area has been heightened since the past ORM recommendations.
“Observing and monitoring ozone is critical as it provides a basis for the nations of the world to take informed decisions and implement policies to protect all life on earth,” said Tina Birmpili, Executive Secretary of the Ozone Secretariat. “We need to convince our policy makers that the stratosphere is a critical part of the earth and that observing and monitoring ozone will reveal critical data and interlinkages with other areas of earth science like climate change”, she added.
“International action on ozone is a shining example of the collaboration needed to address many of the environmental challenges faced by humanity,” said Deon Terblanche, Co-Director of WMO’s Research Department. “The long-term investment in observations and research and capacity development has reaped dividends in terms of the value to society, and it is vital that this should continue,” he said.
Scientists and government managers of research related to ozone attended the meeting. Its recommendations will be submitted to the Meeting of the Conference of the Parties to the Vienna Convention for the Protection of the Ozone Layer, which will be held in November this year in Montreal, Canada.
The key recommendations/findings included:
- It is incumbent on the scientific community to monitor the continued effects of the Montreal Protocol. There is a research need for detailed analyses of the wide range of data on ozone, ODS, their replacements and related gases so that we can assess the impact of the Protocol.
- As most Ozone Depleting Substances are declining, other source gases, especially N2O, CH4, and water vapour, are increasing in importance for understanding Ozone change. Hence increased efforts to monitor vertical profiles of these gases up to the stratosphere will be required.
- A working group between scientist among organizations with significant scientific capacity along with those from organizations with a need for significant increase in scientific capacity should be established to allow continued and enhanced scientific capacity among all parties of the Montreal Protocol.
The ozone layer, the shield that protects life on Earth from harmful levels of ultraviolet rays, is on track to recovery to 1980 benchmark levels by the middle of this century in mid-latitudes and the Arctic, and slightly later in the Antarctic. This is thanks to the near 99 per cent phase-out of ozone destroying substances like chlorofluorocabons (CFCs) and hydrochlorofluorocarbons (HCFCs) and some of their replacements addressed under the Montreal Protocol on Substances that Deplete the Ozone Layer.
Ozone-depleting substances are also powerful greenhouse gases and so their elimination has also been beneficial to the climate and has averted more than 135 billion tonnes of carbon dioxide equivalent emissions.
However, the phase-out of CFCs led to a shift towards the use (in air conditioning and refrigeration) of chemicals known as hydrofluorocarbons, or HFCs. They do not harm the ozone layer but are extremely potent greenhouse gases. It was feared that rapid growth in production and use of HFCs would cancel out the climate gains achieved by the regulation of other ozone-depleting substances.
In October 2016, parties to the Montreal Protocol adopted the Kigali Amendment, which will phase down the production and consumption of global-warming HFCs. Countries who ratify the Kigali Amendment commit to cut the production and consumption of HFCs by more than 80 percent over the next 30 years. Most developed countries will start reducing HFCs as early as 2019.
It is expected that this will avoid up to 0.5° Celsius warming by the end of the century—while continuing to protect the ozone layer.
“While the agreements and implementation of the Montreal Protocol have been crucial in ensuring the protection of the global population from significant loss of stratospheric ozone, the Montreal Protocol has also been an effective climate protection treaty in that it has been instrumental in the overall decrease in in abundances of very effective Greenhouse gases, that otherwise would have amplified the effects of increased CO2 and CH4 on global temperatures.” said Kenneth Jucks, a co-chair of the 10th Ozone Research Managers meeting and NASA Program Scientist for NASA’s stratospheric observations and research activities.
Ozone hole and climate interactions
The Ozone Research Managers meeting discussed wider interactions between stratospheric ozone, weather and climate.
The stratosphere and troposphere are connected. Ozone, as the main heat source in the stratosphere, thus has an effect on the weather below. There is a correlation between ozone amounts in the Arctic stratosphere in March and tropospheric weather in March and April, such as surface temperature. Adding data on the distribution of ozone in the stratosphere can therefore help to improve medium and long range weather forecasts.
A UNEP-WMO Scientific Assessment report in 2014 found that the annual Antarctic ozone hole has caused significant changes in Southern Hemisphere surface climate in the summer.
Ozone depletion has contributed to cooling of the lower stratosphere and this is very likely the dominant cause of observed changes in Southern Hemisphere summertime circulation over recent decades, with associated impacts on surface temperature, precipitation, and the oceans.
What happens to the ozone layer in the second half of the 21st century will largely depend on concentrations of CO2, methane and nitrous oxide – the three main long-lived greenhouse gases in the atmosphere. Overall, CO2 and methane tend to increase global ozone levels. By contrast, nitrous oxide, a by-product of food production, is both a powerful greenhouse gas and an ozone depleting gas, and is likely to become more important in future ozone depletion.
“We cannot look at the ozone layer and the climate system as two separate systems. They are interconnected,” said John Pyle, co-chair of a panel which will produce the next major scientific assessment on ozone in 2018. “The pace of ozone layer recovery will be strongly influenced by the future trajectory of greenhouse gases,” he said.
NOTES TO EDITORS
About the Ozone Research Managers
Ozone Research Managers meet every three years to review ongoing national and international research and monitoring programmes to ensure proper co-ordination of these programmes and identify gaps that need to be addressed. The Ozone Research Managers meetings take place prior to the Meeting of the Conference of the Parties to the Vienna Convention, which also convenes every three years.