The Ozone Hole 2023

British Antarctic Survey Ozone Bulletin

Antarctic Situation at 2023 December 23

Antarctic ozone today:  The 2023 ozone hole is over. The polar vortex began to form in mid May 2023 and grew to reach 33 million square kilometres (msqkm) by mid September, close to average. It shrank slowly till early December, then more rapidly, though at 4 msqkm it is larger than the long term average. It became significantly less stable in the second half of September and remained unstable until late October. The area with potential Polar Stratospheric Clouds (PSC) also began to grow from mid May and reached a peak of around 26 msqkm in mid July.  It declined slowly to 22 msqkm in mid September and it then shrank more rapidly, disappearing by October 24.  An ozone hole formed in late June largely due to dynamical effects, reaching an area of 3 msqkm, before disappearing again. The main ozone hole began to form in late July and grew to 26 msqm in mid September, near the largest over the last decade. It shrank slowly and finally filled on December 19. It remained larger than the average over the last decade, but similar to the last couple of years for the majority of its existence. Ozone values continue to rise over Antarctica and remain higher, though declining over the southern ocean. They currently range from a low of around 230 Dobson Units (DU) within the residual vortex over the Weddell Sea to a high of around 360 DU outside the vortex south of Australia. The tempehrature of the ozone layer over Antarctica is rising, and is now above the -78°C PSC formation threshold throughout the ozone layer. The ozone layer temperature is warmest over Antarctica and declines towards the equator. The ozone hole elongated over South Georgia from September 22 to 25. It stretched towards the tip of South America in early October. The 2023 ozone hole is expected to be over in the next few days.

PSCs were observed from Scotland on December 19 and across England on December 21. Further sightings are likely over the next few days as the -78°C PSC contour at 30 hPa covers most of the UK. There is a small ozone hole to the west of the UK and here ozone values are currently lower than anywhere over Antarctica.

2023 Ozone Hole Ranks 16th Largest, NASA and NOAA Researchers Find

NASA November 1 2023 -Kathryn Cawdrey

Editor’s note: This article has been updated to clarify the ranking of the 2023 ozone hole.  It is the 12th largest single-day hole on record, and the 16th largest when averaged from Sept. 7 to Oct. 13.

The 2023 Antarctic ozone hole reached its maximum size on Sept. 21, according to annual satellite and balloon-based measurements made by NASA and NOAA. At 10 million square miles, or 26 million square kilometers, the hole ranked as the 12th largest single-day ozone hole since 1979.

During the peak of the ozone depletion season from Sept. 7 to Oct. 13, the hole this year averaged 8.9 million square miles (23.1 million square kilometers), approximately the size of North America, making it the 16th largest over this period. 

“It’s a very modest ozone hole,” said Paul Newman, leader of NASA’s ozone research team and chief scientist for Earth sciences at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Declining levels of human-produced chlorine compounds, along with help from active Antarctic stratospheric weather slightly improved ozone levels this year.”

The ozone layer acts like Earth’s natural sunscreen, as this portion of the stratosphere shields our planet from the Sun’s harmful ultraviolet radiation. A thinning ozone layer means less protection from UV rays, which can cause sunburns, cataracts, and skin cancer in humans.

Every September, the ozone layer thins to form an “ozone hole” above the Antarctic continent. The hole isn’t a complete void of ozone; scientists use the term “ozone hole” as a metaphor for the area in which ozone concentrations above Antarctica drop well below the historical threshold of 220 Dobson Units. Scientists first reported evidence of ozone depletion in 1985 and have tracked Antarctic ozone levels every year since 1979.

Antarctic ozone depletion occurs when human-made chemicals containing chlorine and bromine first rise into the stratosphere. These chemicals are broken down and release their chlorine and bromine to initiate chemical reactions that destroy ozone molecules. The ozone-depleting chemicals, including chlorofluorocarbons (CFCs), were once widely used in aerosol sprays, foams, air conditioners, fire suppressants, and refrigerators. CFCs, the main ozone-depleting gases, have atmospheric lifetimes of 50 to over 100 years.

The 1987 Montreal Protocol and subsequent amendments banned the production of CFCs and other ozone-destroying chemicals worldwide by 2010. The resulting reduction of emissions has led to a decline in ozone-destroying chemicals in the atmosphere and signs of stratospheric ozone recovery.

NASA and NOAA researchers monitor the ozone layer over the pole and globally using instruments aboard NASA’s Aura, NOAA-NASA Suomi NPP, and NOAA-20 satellites. Aura’s Microwave Limb Sounder also estimates levels of ozone-destroying chlorine.

Scientists also track the average amount of depletion by measuring the concentration of ozone inside the hole. At NOAA’s South Pole Baseline Atmospheric Observatory, scientists measure the layer’s thickness by releasing weather balloons carrying ozonesondes and by making ground-based measurements with a Dobson spectrophotometer.

NOAA’s measurements showed a low value of 111 Dobson units (DU) over the South Pole on Oct 3. NASA’s measurements, averaged over a wider area, recorded a low of 99 DUs on the same date. In 1979, the average concentration above Antarctica was 225 DU.

“Although the total column ozone is never zero, in most years, we will typically see zero ozone at some altitudes within the stratosphere over the South Pole,” said NOAA research chemist Bryan Johnson, project leader for the Global Monitoring Laboratory’s ozonesonde group. “This year, we observed about 95% depletion where we often see near 100% loss of ozone within the stratosphere.”

The Hunga Tonga-Hunga Ha’apai volcano — which violently erupted in January 2022 and blasted an enormous plume of water vapor into the stratosphere – likely contributed to this year’s ozone depletion. That water vapor likely enhanced ozone-depletion reactions over the Antarctic early in the season.

“If Hunga Tonga hadn’t gone off, the ozone hole would likely be smaller this year,” Newman said. “We know the eruption got into the Antarctic stratosphere, but we cannot yet quantify its ozone hole impact.”

​​Media Contact:
Jacob Richmond
NASA’s Goddard Space Flight Center, Greenbelt, Md.
jacob.richmond@nasa.gov

2023 Ozone Hole Ranks 16th Largest, NASA and NOAA Researchers Find - NASA

21st December 2023 The Copernicus Atmosphere Monitoring Service (CAMS)

The 2023 ozone hole completed its cycle after a series of twists, turns and rebounds that surprised the specialists. The ozone hole opened early and fast, becoming one of the largest on record in mid-September, and it’s one of the longest-lived observed to date. The causes of this behaviour point to climate change or volcanic emissions, but the precise reasons are not yet known.

The 2023 Antarctic ozone hole finally closed on 20 December, becoming the 7th latest closing observed, according to our data. The Southern Hemisphere’s polar stratosphere temperatures rose as forecast by the Copernicus Atmosphere Monitoring Service (CAMS), and winds reduced, leading to a breakup of the polar vortex, allowing the ozone layer in the area to recover. 

The 2023 ozone hole very quickly drew the attention of specialists with an early start, leading to one of the largest ozone holes observed in mid-September of any year.

Later the ozone hole area reduced significantly to become pretty much within the average, but it was unusually persistent during November, remaining over 14.2m2, roughly the area of Antarctica, until early December, becoming the third-largest for the time of the year in the CAMS records.

Then started the closing process, with a series of rebounds that delayed the final closure until 20 December. The longest-lived ozone hole in our data record dating back to 1979 was in 1999 and 2020; both lasted until 27 December. 

It is the fourth year in a row that the Southern Hemisphere’s ozone hole showed peculiar behaviour, despite the global success in banning ozone-depleting substances.

It is the fourth year in a row that the Southern Hemisphere’s ozone hole showed peculiar behaviour, despite the global success in banning ozone-depleting substances.  

Researchers suggest the eruption of the Hunga Tonga - Hunga Ha’apai volcano in early 2022, that injected huge amounts of water vapour into the stratosphere, might have influenced the extent and intensity of ozone depletion in 2023. Other specialists explain that a period of positive Southern Annular Mode could have delayed the “final stratospheric warming” that usually concludes the ozone hole, breaking up the polar vortex.

New research also points to long-term atmospheric dynamics detected since the early 2000s as a potential driver of the large ozone holes observed in recent years, suggesting possible impacts of climate change. 

Even though research has made considerable progress in recent years, there are still gaps in the knowledge of the precise chemical and dynamic processes and the interactions with other layers, due to the difficulties in obtaining observations in this remote region of our atmosphere. 

The challenge of gathering information about our stratosphere

Researchers gather data from stratospheric balloons and satellite observations, but the analysis can take several months or years, and some interactions are not yet well understood, which is why there is not an unequivocal answer to the recent changes observed in ozone hole behaviour.

The ozone layer sits in the stratosphere at between 15 km and 30 km altitude. It protects life on Earth from harmful ultraviolet radiation. In the late 1970s and early 1980s scientists demonstrated that ozone-depleting substances like chlorofluorocarbons (CFC) and hydrofluorocarbons (HFC) accumulated in the stratosphere were causing a seasonal thinning in the Southern Hemisphere’s ozone layer, namely the ozone hole.

Ozone depleting substances got banned by the Montreal Protocol in 1987, but the chlorinated and brominated gases emitted prior to the ban will remain in the atmosphere still for several decades.

Large and persistent 2023 ozone hole closes | Copernicus

NASA Ozone Watch: Latest status of ozone

British Antarctic Survey Ozone Bulletin

Antarctic Situation at 2023 December 8

Antarctic ozone today:  The 2023 polar vortex began to form in mid May and grew to reach 33 million square kilometres (msqkm) by mid September, close to average. It is  slowly shrinking, though at 19 msqkm is now larger than the long term average. It became significantly less stable in the second half of September and remained unstable until late October. The area with potential Polar Stratospheric Clouds (PSC) also began to grow from mid May and reached a peak of around 26 msqkm in mid July.  It declined slowly to 22 msqkm in mid September and it then shrank more rapidly, disappearing by October 24.  An ozone hole formed in late June largely due to dynamical effects, reaching an area of 3 msqkm, before disappearing again. The main ozone hole began to form in late July and grew to 26 msqm in mid September, near the largest over the last decade. It is now shrinking slowly and has declined to 11 msqkm, above the average over the last decade, and larger than in the last couple of years. Ozone values have passed their minimum over Antarctica and remain high over the southern ocean. They currently range from a low of around 180 Dobson Units (DU) within the vortex to a high of around 370 DU outside the vortex between South America and the Antarctic Peninsula. The temperature of the ozone layer over Antarctica is rising, and is now above the -78°C PSC formation threshold throughout the ozone layer. The ozone layer temperature is warmest just outside the polar vortex over the Antarctic Peninsula and declines towards the equator, though there is still a cold pool over East Antarctica. The ozone hole elongated over South Georgia from September 22 to 25. It stretched towards the tip of South America in early October. The ozone hole is expected to continue to shrink and fill over the coming week.

British Antarctic Survey Ozone Bulletin

Antarctic Situation at 2023 October 13

Antarctic ozone today:  The 2023 polar vortex began to form in mid May and grew to reach 33 million square kilometres (msqkm) by mid September, close to average. It has begun to shrink but remains close to average in size at 29 msqkm. It became significantly less stable in the second half of September and remains unstable. The area with potential Polar Stratospheric Clouds (PSC) also began to grow from mid May and reached a peak of around 26 msqkm in mid July.  It declined slowly to 22 msqkm in mid September and is now shrinking more rapidly. It is now at around 6 msqkm, close to average.  An ozone hole formed in late June largely due to dynamical effects, reaching an area of 3 msqkm, before disappearing again. The main ozone hole began to form in late July and grew to 25 msqm in mid September, near the largest over the last decade. It is now shrinking and has declined to 18 msqkm, close to the average over the last decade. Ozone values have passed their minimum over Antarctica and remain high over the southern ocean. They currently range from a low of around 150 Dobson Units (DU) within the vortex to a high of around 500 DU outside the vortex south of New Zealand. The temperature of the bulk of the ozone layer over Antarctica is beginning to rise, but is below the -78°C PSC formation threshold in some lower parts. The ozone layer temperature is warmest just outside the polar vortex and declines towards the equator and towards the pole. The ozone hole elongated over South Georgia from September 22 to 25. It stretched towards the tip of South America in early October.

British Antarctic Survey Ozone Bulletin

Antarctic Situation at 2023 October 2

Antarctic ozone today:  The 2023 polar vortex began to form in mid May and grew to reach 33 million square kilometres (msqkm) by mid September, close to average. It has shrunk a little but remains close to average in size at 32 msqkm. It became significantly less stable in the second half of September. The area with potential Polar Stratospheric Clouds (PSC) also began to grow from mid May and reached a peak of around 26 msqkm in mid July.  It declined slowly to 22 msqkm in mid September and is now shrinking more rapidly. It is now at around 15 msqkm, a little larger than average.  An ozone hole formed in late June largely due to dynamical effects, reaching an area of 3 msqkm, before disappearing again. The main ozone hole began to form in late July and grew to 25 msqm in mid September, near the largest over the last decade. It is now shrinking and has declined to 22 msqkm, still larger than average over the last decade. Ozone values are near their minimum over Antarctica and building over the southern ocean. They currently range from a low of around 120 Dobson Units (DU) within the vortex to a high of around 460 DU outside the vortex over the Pacific Ocean. The temperature of the bulk of the ozone layer over Antarctica is near the winter minimum and is below the -78°C PSC formation threshold in most of it.  It is now rising at the top of the ozone layer where it is above the PSC formation threshold. The ozone layer temperature is warmest just outside the polar vortex and declines towards the equator and towards the pole. The ozone hole elongated over South Georgia from September 22 to 25. It stretched towards the tip of South America in early October.

British Antarctic Survey Ozone Bulletin

Antarctic Situation at 2023 September 29

Antarctic ozone today:  The 2023 polar vortex began to form in mid May and grew to reach 33 million square kilometres (msqkm) by mid September, close to average. It has shrunk a little but remains close to average in size. It became significantly less stable in the second half of September. The area with potential Polar Stratospheric Clouds (PSC) also began to grow from mid May and reached a peak of around 26 msqkm in mid July.  It is now at around 18 msqkm, still larger than average.  An ozone hole formed in late June largely due to dynamical effects, reaching an area of 3 msqkm, before disappearing again. The main ozone hole began to form in late July and grew to 25 msqm in mid September, near the largest over the last decade. It is now shrinking and has declined to 21 msqkm. Ozone values are near their minimum over Antarctica and building over the southern ocean. They currently range from a low of around 130 Dobson Units (DU) within the vortex to a high of around 470 DU outside the vortex over the Pacific Ocean. The temperature of the bulk of the ozone layer over Antarctica is near the winter minimum and is below the -78°C PSC formation threshold in most of it.  It is now rising at the top of the ozone layer where it is above the PSC formation threshold. The ozone layer temperature is warmest just outside the polar vortex and declines towards the equator and towards the pole. The ozone hole elongated over South Georgia from September 22 to 25. It is expected to stretch towards the tip of South America in early October.

British Antarctic Survey Ozone Bulletin

Situation at 2023 September 22

Antarctic ozone today:  The 2023 polar vortex began to form in mid May and has grown to 33 million square kilometres (msqkm) since then and is near its largest. The area with potential Polar Stratospheric Clouds (PSC) also began to grow from mid May and reached a peak of around 26 msqkm in mid July.  It is now at around 22 msqkm, much above average.  An ozone hole formed in late June due to dynamical effects, reaching an area of 3 msqkm, before disappearing again. The main ozone hole began to form in late July and has grown to 24 msqm, near the largest over the last decade. Ozone values are falling over Antarctica and building over the southern ocean. They currently range from a low of around 140 Dobson Units (DU) within the vortex to a high of around 420 DU outside the vortex over the Atlantic and Indian Oceans. The temperature of the ozone layer over Antarctica is near the winter minimum and is below the -78°C PSC formation threshold in most of the Antarctic ozone layer.  The ozone layer temperature is warmest just outside the polar vortex and declines towards the equator and towards the pole. The ozone hole has currently elongated towards South Georgia and ozone depletion is expected to significantly increase over the coming ten days. During this period it will return to a more circular shape.

British Antarctic Survey Ozone Bulletin

Antarctic Situation at 2023 September 15

Antarctic ozone today:  The 2023 polar vortex began to form in mid May and has grown to 32 million square kilometres (msqkm) since then and is near its largest. The area with potential Polar Stratospheric Clouds (PSC) also began to grow from mid May and reached a peak of around 26 msqkm in mid July.  It is now at around 22 msqkm, somewhat above average.  An ozone hole formed in late June due to dynamical effects, reaching an area of 3 msqkm, before disappearing again. The main ozone hole began to form in late July and has grown to 23 msqm, near the largest over the last decade. Ozone values are falling over Antarctica and building over the southern ocean. They currently range from a low of around 140 Dobson Units (DU) within the vortex to a high of around 430 DU outside the vortex over the Indian Ocean. The temperature of the ozone layer over Antarctica is near the winter minimum and is below the -78°C PSC formation threshold in most of the Antarctic ozone layer.  The ozone layer temperature is warmest just outside the polar vortex and declines towards the equator and towards the pole. Ozone depletion is expected to significantly increase over the coming ten days.

British Antarctic Survey Ozone Bulletin

Antarctic Situation at 2023 September 8

Antarctic ozone today:  The 2023 polar vortex began to form in mid May and has grown to 32 million square kilometres (msqkm) since then and is near its largest. The area with potential Polar Stratospheric Clouds (PSC) also began to grow from mid May and reached a peak of around 26 msqkm in mid July.  It is now at around 22 msqkm, close to average.  An ozone hole formed in late June due to dynamical effects, reaching an area of 3 msqkm, before disappearing again. The main ozone hole began to form in late July and has grown to 21 msqm, the largest over the last decade. Ozone values are falling over Antarctica and building over the southern ocean. They currently range from a low of around 160 Dobson Units (DU) within the vortex to a high of around 430 DU outside the vortex over the Southern Ocean. The temperature of the ozone layer over Antarctica is near the winter minimum and is below the -78°C PSC formation threshold in most of the Antarctic ozone layer.  The ozone layer temperature is warmest just outside the polar vortex and declines towards the equator and towards the pole. Ozone depletion is expected to significantly increase over the coming ten days.

British Antarctic Survey Ozone Bulletin

Antarctic Situation at 2023 August 25

Antarctic ozone today:  The 2023 polar vortex began to form in mid May and has grown to 30 million square kilometres (msqkm) since then. The area with potential Polar Stratospheric Clouds (PSC) also began to grow from mid May and reached a peak of around 26 msqkm in mid July.  It is now at around 24 msqkm, close to average.  An ozone hole formed in late June due to dynamical effects, reaching an area of 3 msqkm, before disappearing again. The main ozone hole began to form in late July and had grown to 13 msqm by August 23, which is larger than average. Ozone values are falling over Antarctica and building over the southern ocean. They currently range from a low of around 130 Dobson Units (DU) within the vortex over Halley station to a high of around 430 DU outside the vortex over the Southern Ocean. The temperature of the ozone layer over Antarctica is near the winter minimum and is below the -78°C PSC formation threshold in most of the Antarctic ozone layer.  The ozone layer temperature is warmest just outside the polar vortex and declines towards the equator and towards the pole. Ozone depletion is expected to significantly increase over the coming ten days.

Antarctic Situation at 2023 July 28

Antarctic ozone today:  The 2023 polar vortex began to form in mid May and has grown to 27 million square kilometres (msqkm) since then. It is stable.  The area with potential Polar Stratospheric Clouds (PSC) is also growing and has reached 25 msqkm, close to average.  An ozone hole formed in late June due to dynamical effects, reaching an area of 3 msqkm, before disappearing again. Ozone values are falling over Antarctica and building over the southern ocean. They currently range from a low of around 220 Dobson Units (DU) within the vortex to a high of around 410 DU outside it.  The temperature of the ozone layer over Antarctica is nearing the winter minimum. It is below the -78°C PSC formation threshold in most of the Antarctic ozone layer.  The ozone layer temperature is warmest just outside the polar vortex and declines towards the equator and towards the pole. Ozone depletion is expected to significantly increase over the coming ten days.

The Ozone Hole July 2023

The Ozone Hole August 2023

The Ozone Hole September 2023

The Ozone Hole October 2023

The Ozone Hole November 2023

The Ozone Hole December 2023