An Arctic Ozone
Hole, if similar in size to the Antarctic Ozone Hole, could expose over
700+ million people, wildlife and plants to dangerous UV ray levels. The likely
hood of this happening seems inevitable based on the deterioration of ozone
layer caused by the effects of global warming on the upper atmosphere.
Area
that may be affected by formation of Arctic Ozone Hole
is
the yellow area within the red circle
Area that
may be
affected by formation of Arctic Ozone Hole is above the redline
World
Population Density Map
Area
directly affected is above the red line on these maps
"The
formation of an Ozone Hole occurring over the Arctic will likely happen
within the next 20 years"-
Jonathan
Shanklin one of The BAS scientists who discovered the Antarctic ozone hole-1999
Professor
Jonathan Shanklin of
The British Antarctic Study said the loss itself of ozone and the
greenhouse effect is causing the upper atmosphere to become colder, which
is a condition that facilitates ozone destruction. Professor Shanklin was
speaking to Alex Kirby of the BBC Radio Four's environment program Costing
the Earth and reportedly said the following -
Jonathan
Shanklin of The BAS making ozone measurements
"The
atmosphere is changing, and one of the key changes is that the ozone layer
is getting colder. And when it gets colder, particularly during the
winter, we can get clouds actually forming in the ozone layer, and these
clouds are the key factor.
Chemistry
can take place on them that activates the chlorine and makes it very much
easier for it to destroy the ozone.
It's getting colder because of the greenhouse gases that are being
liberated by all the emissions we have at the surface.
We
think that within the next 20 years we are likely to see an ozone hole
perhaps as big as the present one over Antarctica but over the North
Pole."
Joseph
Farman, Brian Gardiner and
Jonathan Shanklin, are the BAS scientists who discovered the Antarctic ozone
hole.
Professor
Shanklin also is the Director of the British Astronomical Association's
Comet Section and the President of the Cambridge Natural History Society
Arctic Ozone
Hole in The Near Future?
May 25,2000-Upper atmospheric
conditions in The Northern Hemisphere are becoming similar to those of the
Antarctic. The result of this could be the formation of an "Arctic Ozone
Hole" or "low ozone event". The alarming difference is that there
are millions of people that live in the area that will be exposed to this
deadly radiation. These conditions could expose large numbers of people and
animals to more ultraviolet radiation, which can cause skin cancer and disrupt
reproduction of some animals and destroy plant life.
December 2,1999
An Arctic "
low ozone event" could easily be blown south by high-altitude winds, and
appear over populated areas of The United States, Canada, Europe and Asia. It
could trigger public alerts against going out in the sun without protective
clothing across The Northern Hemisphere. Experts predict that an estimated 10 %
reduction in the ozone layer will result in a 25 % increase in non-melanoma skin
cancer rates for temperate latitudes by the year 2050.
ARCTIC OZONE MAY NOT RECOVER AS EARLY AS PREDICTED
NASA Press Release 5/25/2000
The ozone layer that protects life on Earth may not be recovering from
the damage it has suffered over the Arctic region as quickly as scientists
previously thought, according to a paper published in the May 26 issue of
the journal Science. Specifics of the research also will be
presented at the annual meeting of the American Geophysical Union in
Washington, DC, on May 31.
More polar stratospheric clouds than anticipated
are forming high above the North Pole, causing additional ozone loss in
the sky over the Arctic, according to Dr. Azadeh Tabazadeh, lead author of
the paper and a scientist at NASA's Ames Research Center in California's
Silicon Valley. The stratosphere comprises Earth's atmosphere from
about 9 to 25 miles (about 15 to 40 kilometers) altitude and includes the
ozone layer.
Arctic polar stratospheric clouds
"Polar stratospheric clouds provide a
'double-whammy' to stratospheric ozone. They provide the surfaces
which convert benign forms of chlorine into reactive, ozone-destroying
forms, and they remove nitrogen compounds that act to moderate the
destructive impact of chlorine," said Dr. Phil DeCola, Atmospheric Chemistry Program
Manager at NASA Headquarters, Washington, DC.
"The Arctic has become colder and more humid,
conditions that promote formation of more polar stratospheric clouds that
take part in polar ozone destruction. The main conclusion of our
study is that if this trend continues, Arctic clouds will remain longer in
the
stratosphere in the future," Tabazadeh said.
"An ozone hole forms every spring over the
Antarctic in the Southern Hemisphere which is colder than the
Arctic," said Tabazadeh. "The Arctic has been getting
colder and is becoming more like the Antarctic; this could lead to more
dramatic ozone loss in the future over the Northern Hemisphere, where many
people live."
NASA's
Upper Atmosphere Research Satellite
Researchers used data from NASA's Upper
Atmosphere Research Satellite to analyze cloud data from both the north
and south polar regions for the study. "What we found from the
satellite was that polar stratospheric clouds currently last twice as long
in the Antarctic as compared to the Arctic," Tabazadeh said. "However, our
calculations show that by 2010 the Arctic may become more 'Antarctic-like'
if Arctic temperatures drop further by about 5 to 7 degrees Fahrenheit
(about 3 to 4 degrees Celsius)," she said.
Environment Canada
Nov 30 1999 ozone
image
When Arctic polar stratospheric clouds last
longer, they can precipitate, removing nitrogen from the upper atmosphere,
which increases the opportunity for chlorine compounds to destroy ozone more efficiently. The polar stratospheric
clouds involved in the reactions contain nitric acid and water, according
to researchers who discovered these clouds in 1986.
"Data from the Microwave Limb Sounder on
UARS have provided the first opportunity to observe nitric acid throughout
the Arctic and the Antarctic over a period of many years," said
Michelle Santee, a scientist at NASA's Jet Propulsion Laboratory,
Pasadena, CA, who is a co-author of the Science paper. "The continued presence of
nitric acid in the Arctic winter -- which is not the case in the
Antarctic -- helps to moderate ozone loss by reducing the amount of
reactive chlorine, but this could change in the future," she added.
More than a decade ago, scientists determined
that human-made chlorine and bromine compounds cause most ozone depletion.
Manufacturers made the chlorine compounds,chloroflourocarbons or
"CFCs," for use as refrigerants, aerosol sprays, solvents and
foam-blowing agents. Fire fighters used bromine-containing halogens to
put out fires. Manufacture of CFCs ceased in 1996 in signatory countries
under the terms of the Montreal Protocol and its amendments.
The Montreal Protocol bans CFC emissions. As a
result, the chlorine concentration in the upper atmosphere is already
starting to decline, according to Tabazadeh. "Scientists used
to believe that as chlorine levels decline in the upper atmosphere, the
ozone layer should slowly start to recover. However, greenhouse gas emissions, which
provide warming at the Earth's surface, lead to cooling in the upper
atmosphere. This cooling promotes formation of the kind of polar
stratospheric clouds that contribute to ozone loss," she added.
"Several recent studies, including this one, show that ozone recovery
is more complex and will take longer than originally thought," she
explained.
Arctic Ozone 2011
Recent observations
from satellites and ground stations suggest that atmospheric ozone levels for
March 2011 in the Arctic were approaching the lowest levels in the modern
instrumental era. What those readings mean for the remainder of the year is
unclear. But what they mean for the long-term is that the recovery from
human-induced ozone depletion is an uneven climb.
These maps of ozone concentrations over the Arctic come from the Ozone
Monitoring Instrument (OMI) on NASA's Aura satellite. The left image shows
January 1 to March 23, 2010, and the right shows the same dates in 2011. March
2010 had relatively high ozone, while March 2011 has low levels.
This shows, from 20
February until 4 April, the ozone abundance in the lower stratosphere
where ozone depletion is most intense. The smaller globe shows values
reached in a more common year (2010). One sees that this "ozone
hole" reached Scandinavia at the end of March and is now weakening.
It will very probably disperse in the coming weeks.
The data comes from ECMWF
and is generated for the European project MACC, in which BIRA-IASB is in
charge of the stratospheric ozone service. These results combine several
satellite instruments within a new "chemical weather" model
named IFS-MOZART and developed by ECMWF and the Jülich Research Centre.
The 3-D fields were then interpolated to the 470K isentropic level in
order to follow the vertical movements of the air masses in the lower
stratosphere.
Polar
ozone loss depends on temperature and inorganic halogen concentrations
in lower stratosphere
Assessments
in 1990s recognized that could have severe Arctic ozone depletion in
very cold Arctic winters
Low
temperatures into spring are key ingredient for large ozone loss
Stratospheric
minimum temperatures in 2010/2011 were unusually low/long lasting
High levels
of Activated Chlorine observed in Arctic in March 2011
As a result of the
high Cl levels, there were large ozone losses
Credit:Professor
Jonathan Pyle from University Cambridge
It was exceptionally cold
in the ozone layer in the past month. During the first half of March there
were several days with record-low temperatures in the stratosphere at
altitudes of about 20 km, and the cold period continued for the entire
month. This led to sustained low ozone values over the polar region.
The area with low ozone
over the North Pole was observed by several satellite sensors, e.g.
SCIAMACHY on the EnviSat satellite, and the Ozone Monitoring Instrument
OMI on EOS-Aura. This is demonstrated by the figure, which shows the
monthly-mean ozone amount for March 2011 compared to the months March in
the period 1979-2010. The situation this year resembles the years 1996,
1997 and 1990, where similar low ozone levels over the North Pole were
observed.
The continuing cold spell
in the stratosphere, where the ozone layer is located, was remarkable. In
contrast, the previous years 2009 and 2010 showed an early so-called
stratospheric warming in January and mid-February. Temperatures in the
stratosphere in the first half of March this year were low enough for
polar stratospheric clouds to form. In these clouds chlorine compounds are
formed from CFCs which break down ozone over the North Pole when sunlight
is present. In addition to the cold temperatures, the transport of
ozone-rich air from the tropics was reduced this year because of the
strong winds around the North Pole at 20km altitude.
The ozone layer over the
North Pole nevertheless has a thickness of more than 250 Dobson units (a
unit expressing the number of molecules ozone per square meter). This is
much more than what is observed for the ozone hole over the South Pole in
September-November. 250-300 DU is comparable to the thickness of the ozone
layer in the tropics. The relatively large ozone breakdown leads to
reduced ozone levels over the Northern Hemisphere this Spring because it
will take some time before the lost ozone has been replenished.
The figure above shows the
March monthly-mean total ozone values for the period 1979-2011 as it is
monitored by MACC partner KNMI. The period 1979-2008 is derived from the
multi-sensor reanalysis (MSR) of the ozone layer. The analysis for
2009-2011 is based on an assimilation of SCIAMACHY ozone columns.
