World Video | Defence | Foreign Affairs | Natural Events | Trade | NZ in World News | NZ National News Video | NZ Regional News | Search

 

Antarctic Ozone Hole at Near Record Size This Year


Antarctic Ozone Hole at Near Record Size This Year

Large size due to cold temperatures

Cold temperatures over Antarctica this year have resulted in an ozone "hole" that is the second largest ever observed, according to U.S. scientists. The ozone hole is caused by ozone-depleting chemicals from human activity.

According to an October 7 press release, researchers report that the observed size of the ozone depletion region in 2003 is strikingly larger than the hole in 2002, the size of which was considered a quirk of meteorological conditions over Antarctica due to warmer-than-normal stratospheric temperatures. The difference in the size of the ozone hole is directly attributed to year-to-year temperature variations, not an increase in the amount of ozone-depleting compounds in the atmosphere.

"In colder years, the same amount of ozone-depleting compounds can destroy more ozone, in comparison to warmer years," said Daniel Albritton, director of the Aeronomy Laboratory at the National Oceanic and Atmospheric Administration.

According to measurements by balloon instruments, the size of this year's Antarctic ozone hole reached 28.3 million square kilometers on September 11, smaller than September 10, 2000, the largest ever hole recorded when it covered 29.9 million kilometers. Last year the ozone hole was smaller, covering 21 million square kilometers.

The ozone layer blocks harmful ultraviolet rays that have been linked to skin cancer in humans and other adverse biological effects on plants and animals.

Chlorine and bromine-containing compounds from human activity are the primary cause of ozone hole, which is defined as a thinning of the ozone layer to levels significantly below those seen prior to 1979. While the 1987 Montreal Protocol and subsequent amendments sharply curtailed the use of these compounds, scientists say the chemicals will remain active in the atmosphere for several decades. The ozone hole is expected to recover in about 50 years.

Following is the text of the press release:

(begin text)

National Oceanic and Atmospheric Administration
October 7, 2003

2003 ANTARCTIC OZONE ‘HOLE' NEAR RECORD SIZE; COLD TEMPERATURES PLAY MAJOR ROLE

This year's Antarctic ozone "hole" is the second largest ever observed, according to scientists from the National Oceanic and Atmospheric Administration (NOAA), NASA, and the Naval Research Laboratory.

The size of the ozone depletion region shows an increase in its total size from last year, further indicating that the relatively smaller hole of 2002 was mostly a quirk of meteorological conditions over Antarctica. The difference is directly attributed to year-to-year temperature variations across the Antarctic continent, not an increase in the amount of ozone-depleting compounds in the atmosphere.

"We expect to see year-to-year variations in the size of the ozone hole, because stratospheric temperatures can vary from year to year. In colder years, the same amount of ozone-depleting compounds can destroy more ozone, in comparison to warmer years," said Daniel L. Albritton, director of the NOAA Aeronomy Laboratory in Boulder, Colo.

The Antarctic ozone "hole" is defined as thinning of the springtime ozone layer to levels significantly below those seen prior to 1979. Extreme cold in the upper atmosphere is one key factor that affects the amount of ozone loss caused by ozone-depleting compounds. Year-to-year changes in the size and amount of depletion in the vertical column of the ozone hole are dominated by the year-to-year variations in temperature in this part of the atmosphere.

Chlorine- and bromine-containing compounds from human activity are the primary cause of ozone depletion. The 1987 United Nations Montreal Protocol and its subsequent amendments sharply curtailed the use of chlorine-containing chlorofluorcarbons (CFCs) and bromine-containing halons. Because of the protocol, the amounts of these ozone-depleting substances have begun to decline in the lower atmosphere and to level off in the stratosphere, where the ozone layer resides.

"Although international protocols have greatly reduced the production and release of ozone depleting chemicals, they will remain active in the stratosphere for several decades," said James Laver, Director of NOAA's Climate Prediction Center. "With the protective atmospheric layer so compromised, greater amounts of ultraviolet radiation may be allowed to reach the surface and potentially increase certain health risks." NOAA provides predictions of expected levels of ultraviolet radiation in support of the Environmental Prediction Agency‘s Sunwise program.

At South Pole Station, balloon-borne ozone-measuring instruments launched by NOAA's Climate Monitoring and Diagnostics Laboratory reveal the vertical structure of the developing ozone hole. An important gauge for identifying when future recovery of the Antarctic ozone hole begins is the severity of depletion observed in the upper atmosphere near the main ozone layer.

Ozone measured by a balloon instrument on Sept. 26 showed nearly complete ozone destruction in the 9-13 mile altitude layer. Total column ozone indicated a 60 per cent drop from early August measurements.

"This year, ozone depletion over the South Pole, from 7-to-14 miles above Antarctica, has shown large losses, similar to losses seen in the 1990s," said Bryan Johnson of NOAA's Climate Monitoring and Diagnostics Laboratory.

Ozone blocks harmful ultraviolet "B" rays. Prolonged over-exposure to ultraviolet radiation has been linked to skin cancer in humans and other adverse biological effects on plants and animals. The dramatic ozone "hole" exists only over Antarctica, but currently, the ozone layer over the United States is depleted by about 6 percent.

Temperature over the Antarctic affects the formation of polar stratospheric clouds, which accelerate the destruction of stratospheric ozone by human-produced chlorine and bromine compounds. The Antarctic ozone hole is still expected to recover in about 50 years, when the atmospheric amounts of reactive chlorine and bromine return to their pre-ozone-hole levels.

The observed size of the ozone depletion region in 2003 is a stark contrast from 2002. The reduced size in 2002 was attributed to warmer-than-normal stratospheric temperatures and temperature patterns above Antarctica. The size of this year's Antarctic ozone hole reached 10.9 million square miles on Sept. 11, 2003, smaller than Sept. 10, 2000, the largest ever recorded when it covered 11.5 million square miles. Last year the ozone hole was smaller, covering 8.1 million square miles.

NOAA is dedicated to enhancing economic security and national safety through the prediction and research of weather and climate-related events and providing environmental stewardship of our nation's coastal and marine resources. To learn more about NOAA, please visit: http://www.noaa.gov.

For more information on ozone research, please visit: http://www.ozonelayer.noaa.gov


© Scoop Media

 
 
 
World Headlines

 

UN: India’s New COVID-19 Wave Is Spreading Like ‘Wildfire’, Warns UN Children’s Fund

7 May 2021 A new wave of COVID-19 infections is spreading like “wildfire” across India, leaving many youngsters destitute, the UN Children’s Fund UNICEF said on Friday. In the last 24 hours, India registered 3,915 coronavirus deaths and 414,188 ... More>>

UN: Decades Of Health Gains At Risk In Brazil Due To COVID-19

Although COVID-19 cases are declining in Brazil, the pandemic is putting decades of public health gains there at risk, the head of the World Health Organization ( WHO ) said on Friday. With global attention and support focused this week ... More>>

UN Report: Myanmar Approaching Point Of Economic Collapse

The turmoil following the military coup in Myanmar, coupled with the impact of COVID-19 could result in up to 25 million people – nearly half of the country’s population, living in poverty by early next year, a United Nations report said on Friday. That ... More>>


Focus On: UN SDGs

Study: Cut Methane Emissions To Avert Global Temperature Rise

6 May 2021 Methane emissions caused by human activity can be reduced by up to 45 per cent this decade, thus helping to keep global temperature rise to 1.5 degrees Celsius in line with the Paris Agreement on climate change, according to a UN-backed ... More>>

UN: Learning From COVID-19, Forum To Highlight Critical Role Of Science, Technology And Innovation In Global Challenges

New York, 4 May —To build on the bold innovations in science, technology and innovations that produced life-saving solutions during the COVID-19 pandemic, the UN will bring together experts to highlight measures that can broaden the development and deployment ... More>>

What COVID-19 Has Taught Us: “Healthcare Can No Longer Exist Without Technology”

A grandmother in a village in the Gambia should have the same quality of life and access to healthcare they deserve as in New York or London. Photo: InnovaRx Global Health Start-up Works To Bridge Healthcare Gap In The Gambia By: Pavithra Rao As ... More>>