- The ozone layer protects the earth from the harmful ultraviolet rays of the sun
- Every year between August and October a ‘hole’ opens over the South Pole.
- Since the late 80s, the use of chemicals that sharpen pores was phased out.
- However, some are still present in the atmosphere today.
- The size of the annual ozone hole is also affected by weather conditions.
- Last year’s hole was also the largest on record due to a cold polar vortex
- Despite this, experts still predict that the hole will be permanently closed by 2050.
The annual hole in Earth’s protective ozone layer that is visible over the Southern Hemisphere is ‘larger than normal’ – and is currently larger than Antarctica.
Acting like a shield, ozone absorbs UV light from the sun. Its absence means that this high-energy radiation reaches Earth, where it can damage living cells.
The ozone layer is depleted by chemical reactions powered by solar energy, which include by-products of man-made chemicals that remain in the atmosphere.
Every year, it causes a hole to form at the South Pole between August and October – the southern hemisphere’s heat – peaking in early October.
The size of the hole largely depends on the weather conditions. Last year saw the greatest of cold conditions on record, while 2019 was the shortest.
The European Union’s Copernicus Atmosphere Monitoring Service said the hole has widened significantly over the past week, after an average start this year.
As of yesterday, the hole covered an area of about 8.8 million square miles (23 million sq km).
In years with normal weather conditions, the hole typically grows to a maximum area of about 8 million square miles (20.7 million square kilometers).
Despite these natural fluctuations, experts expect the hole to close permanently by 2050, in response to restrictions on ozone-depleting chemicals introduced in 1987.
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The annual hole in Earth’s protective ozone layer that is visible over the Southern Hemisphere is ‘larger than normal’ – and is currently larger than Antarctica. Image: A map of the ozone hole over Antarctica as seen on September 16, 2020
The size of the ozone hole largely depends on weather conditions. Last year’s cold conditions (blue) saw one of the greatest on record, while 2019’s (green) was the smallest. This year’s dimensions are shown in red above
Improve ozone measurement
Most ozone-monitoring satellites provide a value for the amount of ozone in a column of air moving from the ground to the atmosphere’s boundary.
However, to obtain a complete picture, profiles showing the concentration of ozone levels at different altitudes are also needed along these pillars.
ESA’s ALTIUS (Atmospheric Organ Tracker for Upcoming Stratosphere Investigations) mission, to be launched in 2025, will help in this regard.
ALTIUS is able to view ozone ‘side-on’, allowing it to provide a vertical profile of atmospheric ozone concentrations along with other compounds including nitrogen dioxide, water vapor and aerosols.
This data will not only help in monitoring the status of the ozone layer but will also improve weather forecasting and monitoring of long-term trends.
“Forecasts suggest that this year’s hole has become larger than normal,” said Vincent-Henri Puch, head of the Copernicus Atmosphere Monitoring Service.
‘We are looking at a very large and potentially deep ozone hole.’
According to Dr Puch, the ozone hole seen last year also began unusually, but turned into one of the longest-lasting manifestations of the event on record.
In fact, measurements from the Copernicus Sentinel-5P satellite showed that last year’s hole was also the largest and deepest in recent years, reaching about 9.7 million square miles (25 million square kilometers) in total area. .
According to the European Space Agency, last year’s hole was driven by a ‘strong, stable and cold polar vortex’ that steadily lowered the temperature of the ozone layer over Antarctica.
This year’s ozone hole growth is proceeding along a similar path, currently larger than 75 percent of holes since 1979 for this time of season.
“This ozone evolution is what we would expect given the current atmospheric conditions,” said Antje Innes, senior scientist at the European Center for Medium-Range Weather Forecasts.
‘The progress of the ozone hole in the coming weeks will be extremely interesting.’
This year, Dr Puch said, ‘the vortex is fairly stable and the stratospheric temperature is even lower than last year – so [the ozone hole] May continue to increase slightly in the next two or three weeks.
Measurements from the Copernicus Sentinel-5P satellite (pictured) showed that last year’s hole was the largest in recent years – reaching about 9.7 million square miles in area.
What are CFCs?
Chlorofluorocarbons (CFCs) are non-toxic, non-flammable chemicals that contain atoms of carbon, chlorine and fluorine.
They are used in the manufacture of aerosol sprays, as blowing agents for foams and packing materials, as solvents, and as refrigerants.
CFCs are classified as halocarbons, a class of compounds that contain both carbon and halogen atoms.
Individual CFC molecules are labeled with a unique numbering system.
For example, the CFC number 11 indicates the number of atoms of carbon, hydrogen, fluorine, and chlorine.
While CFCs are safe to use in most applications and are inert in the lower atmosphere, they undergo significant reactivity in the upper atmosphere or stratosphere where they cause damage.
‘Sentinel-5P ozone measurements are an important contribution to global ozone monitoring and forecasting in the frame of the Copernicus programme,’…