World Ozone Day 16 September: The ozone layer continues to recover
Photo: Rigel Kivi.The ozone layer in the upper atmosphere protects the Earth from harmful ultraviolet radiation from the sun. Forty years ago, nations came together under the Vienna Convention for the protection of the ozone layer and agreed to take appropriate measures to stop using ozone-destroying substances.
They succeeded – the use of substances that destroy the ozone layer was limited in the Montreal Protocol in 1987. The latest WMO report confirms the success of the Montreal protocol: ozone-destroying substances (ODS) are declining in the atmosphere, and the signs of ozone recovery are observed.
"The ozone hole in 2024 was smaller than previous years. However, ozone recovery is a long process; thus, continuous ozone monitoring is needed. Climate change increases variability and extreme events, which complicate further the detection of long-term ozone changes", says Kaisa Lakkala, Research Scientist at Finnish Meteorological Institute.
This year's World Ozone Day theme is "From Science to Global Action." It encourages researchers worldwide to turn their findings into action, as was done with the Vienna Convention to protect the ozone layer.
Finnish Meteorological Institute measures ozone in Helsinki, Jokioinen and Sodankylä
The state of the ozone layer and the success of the Montreal Protocol are closely monitored worldwide.
"The Finnish Meteorological Institute conducts ozone measurements in Helsinki, Jokioinen and Sodankylä. Ozone soundings and spectroradiometer measurements have been conducted in Finland since late 1980’s", says Rigel Kivi, Senior Scientist at the Finnish Meteorological Institute.
The measurements monitor both short-term and multi-year ozone developments. The profile and total column measurements show significantly low ozone values during the years of severe polar spring-time ozone loss of the 90’s and e.g. in 2011 and 2020. Then, the northern polar vortex has been particularly cold and therefore the conditions in the upper atmosphere have been conducive to ozone depletion.
The Finnish Meteorological Institute actively participates in the European Space Agency's ESA Ozone Climate Change Initiative and the EU's Copernicus Climate Change project by creating long-term datasets of ozone profiles and assessing ozone development.
Solar UV radiation is monitored in Finland and globally
The ozone layer protects the Earth from excessive ultraviolet radiation from the sun, which is why the implementation of the Montreal Protocol is also monitored through UV radiation measurements. Finnish Meteorological Institute measures UV index at seven measurement stations around Finland. The Finnish Meteorological Institute also monitors the development of the ozone situation in Antarctica as part of an Argentinian Finnish collaboration at the Marambio research station, where UV radiation and ozone are measured, among other atmospheric composition parameters.
The Finnish Meteorological Institute develops and processes several satellite-based surface UV products as part of ESA, EUMETSAT and EU activities. The most recent Metop-SGA1 satellite, launched in August 2025, has onboard the Sentinel 5 instrument, which data will be used to produce global surface UV radiation information for general public and research purposes.
This year, the writing process for the next UN and WMO Ozone Assessment, which is published every four years, began. This assessment compiles the main achievements and observations of global ozone research to adequately track and communicate the state of the atmosphere and the success of the Montreal Protocol. FMI’s researchers contribute actively to the assessment as writers and reviewers.
Further information:
Senior Research Scientist Rigel Kivi, Finnish meteorological institute, rigel.kivi@fmi.fi, tel. 040 542 4543
Research Scientist Kaisa Lakkala, Finnish meteorological institute, kaisa.lakkala@fmi.fi, tel. 040 747 6792
Senior Research Scientist Viktoria Sofieva, Finnish meteorological Institute, viktoria.sofieva@fmi.fi, tel. 050 380 3413