=======================Electronic Edition========================
RACHEL’S HAZARDOUS WASTE NEWS #285
—May 13, 1992—
News and resources for environmental justice.
——
Environmental Research Foundation
P.O. Box 5036, Annapolis, MD 21403
Fax (410) 263-8944; Internet: erf@igc.apc.org
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BUSINESS AS USUAL: LOST IN THE OZONE
The ozone hole over the south pole this past winter grew to be
four times as large as the United States, the biggest it has ever
been. Since 1970, the south-pole ozone hole has opened up each
year between August and December, then closed up again as
sunlight created a new supply of ozone, leaving Earth’s entire
ozone supply slightly more diminished each passing year.
The source of the problem is industrial chemicals (CFCs, halons
and others containing chlorine and bromine), which waft upward
into the sky where they break into smaller molecules. These
smaller molecules remain in the stratosphere, nine to 18 miles
above the earth, until they encounter frozen clouds. Frozen
clouds break down the small molecules further, releasing pure
chlorine and bromine which then begin to devour nearby ozone
molecules that ordinarily protect Earth from deadly ultraviolet
radiation, which is constantly streaming in from the sun.
According to NASA [National Aeronautics and Space Administration]
a one-percent reduction in the ozone shield produces a 2%
increase in ultraviolet radiation on the ground.[1]
In early February this year, NASA announced that conditions were
ripe for development of a huge ozone hole over the NORTH pole for
the first time. In the northernmost region of the stratosphere,
NASA scientists had measured chlorine monoxide levels higher than
previously seen anywhere in the stratosphere. When chlorine
monoxide encounters a frozen cloud, chlorine is released and
ozone destruction begins immediately. At a hastily-called press
conference February 3rd NASA scientists said this spring the
north pole ozone hole might get big enough to cover most of
Canada, northern New England, and northern Europe. This would
place large human populations beneath an ozone hole for the first
time. NASA said in February ozone losses up to 30% might occur
this spring over Toronto and Boston. This would be a significant
reduction indeed. Environment Canada, the Canadian equivalent of
EPA (U.S. Environmental Protection Agency) immediately
recommended that children under 18 be kept indoors throughout the
spring. But within a week, this alarming and unrealistic
recommendation had changed into “normal prudence should be used,”
whatever that might mean.
Fortunately, almost immediately after NASA’s announcement, a
warming trend melted the frozen clouds over the arctic and this
year’s ozone-depletion-season ended after ozone loss of only 10%.
NASA called the 10% loss “quite significant” but said it should
not be called a “hole.” Ozone loss inside the south-pole ozone
hole each year now routinely reaches 50% or more but relatively
few humans are affected.
NASA says it now knows that ozone destruction depends on two main
factors: the total amount of chlorine and bromine atoms in the
stratosphere, and the length of the cold season when
stratospheric temperatures dip below -78 Centigrade (-108
Fahrenheit), forming frozen clouds that release chlorine and
bromine.
As soon as the cold season ends, pure chlorine and bromine change
back into a less-destructive form, and sunlight proceeds to
create a new batch of ozone at the rate of 350,000 tons per day,
partially replenishing Earth’s acutely depleted supply. But
nature produces the same amount of new ozone each year whereas
humans destroy MORE of the Earth’s ozone each year, so Earth’s
total (average) ozone supply is being diminished, allowing
slightly more ultraviolet light to reach Earth’s surface each
year.
Therefore the ozone problem has two parts: large short-term
“holes” that can allow large amounts of ultraviolat light to
strike the earth during spring and early summer (August-December
over the south pole, February-June over the north). And the
long-term depletion of ozone, producing smaller increases of
ultraviolet light over much larger areas year-round.
Despite the reprieve from NASA’s worst fears about a northern
ozone hole, 1992 was not a good year for Earth’s ozone shield:
** During January, February, and March, NASA’s TOMS [Total Ozone
Monitoring Spectrometer] satellite measured average ozone over
the northern hemisphere lower than any previous year in the
satellite’s 13-year history.
** Over the north pole, ozone normally reaches a peak during late
winter, but this year the late-winter peak was 10 to 15% lower
than any peak previously measured.
**The threat of a northern “hole” will be with us for several
decades. In 1991/92, frozen clouds in the north lasted only 39
days, saving us from a severe ozone hole over populous regions.
But the average winter has 68 days of frozen clouds. In a cold
year, frozen clouds can last considerably longer; for example, in
1988/89 frozen clouds lasted 79 days. Thus NASA says it expects
large ozone holes over northern latitudes during many years in
the next two decades.
** One major source of the problem, chlorine monoxide (derived
from CFCs and a few other chemicals like carbon tetrachloride),
is increasing in the stratosphere at about 5% per year, NASA said
in April.
** Even if the Montreal ozone treaty of 1987 and its June, 1990,
amendments are accepted world-wide, it will be 80 years before
Earth’s ozone returns to normal.
The bad news of 1992 followed close on the heels of a series of
unwelcome revelations in late 1991.
Daniel Albritton, directory of the Aeronomy Laboratory for NOAA
[National Oceanic and Atmospheric Administration] testified
before Congress November 15, 1991, giving a litany of trouble:[2]
(a) During the period 1970 through the mid-’80s, ozone depletion
got worse one year then better the next; every other year brought
some relief. But in the late ’80s through today, the situation
has steadily worsened every year. Scientists are not sure why the
pattern has changed, but it apparently has, Albritton said.
(b) In the 1970-1991 period total ozone depletion over northern
mid-latitudes (where the U.S. population resides) ozone depletion
occurred at the rate of 2.7 percent per decade. But during the
later part of this period, 1979-1991, ozone depletion accelerated
to 4.7% per decade. Thus total ozone destruction is accelerating.
Albritton’s picture of accelerating ozone loss was confirmed by
new analyses announced in SCIENCE magazine April 17.[3]
(c) In the 1970s and early ’80s, ozone loss was restricted to
winter time. However in recent years, ozone depletion has also
been observed during summer. Over northern mid-latitudes during
the period 1979-1991, summer ozone losses averaged 3.3%
NASA doesn’t talk much about what ozone depletion means. For one
thing, information is scarce. This scarcity did not occur by
chance. Of all the money spent worrying about the ozone hole(s)
during the past 20 years, less than 1% has been spent measuring
effects of ultraviolet light on living things like plankton,
peas, polar bears, and people. Over 99% of the money has been
spent outfitting airplanes with special equipment, building
satellites with special eyes for seeing ozone, and so forth.
As a result, effects of modest ozone loss are poorly understood.
However, effects of severe ozone loss were studied in 1975 by the
National Academy of Sciences (NAS) as part of an effort to
understand the consequences of nuclear war. The Arms Control and
Disarmament Agency in 1978 used the NAS study to assess effects
of nuclear conflict. According to the Agency, a 50% reduction in
Earth’s ozone shield over mid-latitudes “would cause blistering
after one hour of exposure. This leads to the conclusion that
outside daytime work in the northern hemisphere would require
complete covering by protective clothing…. It would be very
difficult to grow many (if any) food crops, and livestock would
have to graze at dusk, if there were any grass to eat.” [Quoted
in reference 4.]
Besides severe blistering, ultraviolet light harms the immune
systems of humans and animals (regardless of skin pigmentation);
reduces crop yields; reduces the growth of phytoplankton (which
form the basis of all oceanic food chains); and causes eye
cataracts in humans and animals, leading to blindness.
Ozone losses less than 50% might cause blindness in domestic
animals, thus disrupting agriculture in much of Asia which
depends heavily on beasts of burden. Other complex, far-reaching
negative effects are thought possible.
The Institute for Energy and Environmental Research (IEER), a
private organization, has developed a practical plan for rapid
phase-out of all ozone-destroying chemicals,[4] but the Bush
administration has shown no real interest. After the NASA press
conference in February, Mr. Bush speeded up the U.S. timetable
for phasing out ozone-killing chemicals, but only by one year. In
Washington, it’s business as usual.
–Peter Montague, Ph.D.
Descriptor terms: ozone; nasa; south pole; ozone hole; ozone
depletion; nas; ieer;