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Ozone Hearing-Albritton March 16
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Ozone Hearing-Albritton March 16
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FOIA Number: 2012-0769-F
FOIA
MARKER
This is not a textual record. This is used as an
administrative marker by the William J. Clinton
Presidential Library Staff.
Collection/Record Group:
Clinton Presidential Records
Subgroup/Office of Origin:
Council on Environmental Quality
Series/Staff Member:
Kathleen (Katie) McGinty
Subseries:
OA/ID Number:
2613
FolderID:
Folder Title:
Ozone Hearing - Albritton March 16
Stack:
Row:
Section:
Shelf:
Position:
S
61
5
6
2
TESTIMONY OF
DR. DANIEL L. ALBRITTON
DIRECTOR, AERONOMY LABORATORY
ENVIRONMENTAL RESEARCH LABORATORIES
NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION
U.S. DEPARTMENT OF COMMERCE
BEFORE THE
SUBCOMMITTEE ON SCIENCE, TECHNOLOGY, AND SPACE
COMMITTEE ON COMMERCE, SCIENCE, AND TRANSPORTATION
UNITED STATES SENATE
APRIL 16, 1991
Mr. Chairman and Members of the Subcommittee:
My name is Daniel L. Albritton. I am Director of NOAA's
Aeronomy Laboratory in Boulder, Colorado, which studies the
chemistry and dynamics of the Earth's atmosphere. Scientists of
our Laboratory have played major roles in the recent advances in
ozone science. I have also been involved in providing scientific
advice to policymakers during this period. Therefore, I
appreciate the invitation to present testimony to describe the
current scientific understanding of stratospheric ozone and its
relation to the policy decisions that lie ahead.
The key points that I will cover are: (1) the background to
the stratospheric ozone issue; (2) the first world response,
i.e., the 1987 Montreal Protocol; (3) the intensive research of
the period that followed the Protocol; (4) the 1990 Amendments to
the Protocol based on that the research; and (5) the scientific
questions that we still face. As you requested, my remarks will
be aimed at providing the context for the testimonies that
follow.
A. Background
As you well know, the issue of stratospheric ozone depletion
by man-made chlorine-containing compounds was first raised in
1974. In 1979, the United States banned the sale of
chlorofluorocarbons (CFCs) in aerosol spray cans, since a thinner
ozone layer would imply an increase of harmful ultraviolet
radiation at the Earth's surface.
In the years that followed, a major emphasis in stratospheric
research was the building of a better theoretical understanding
of stratospheric processes and a testing of that understanding by
ozone monitoring and other observations. By the mid-1980s,
theoretical models were predicting that about 1 percent global
ozone depletion should be occurring by then (1985) and that, if
CFC emissions continued to grow, ozone depletion would very
likely grow to several percent in the next century. Furthermore,
it had become clear that (1) there were growing uses of other
ozone-depleting compounds, such as the bromine-containing halons
used in fire extinguishers; and (2) the CFCs were also
particularly efficient "greenhouse" molecules and hence related
significantly to the global warming issue.
While the ozone monitoring record and analysis in 1985 could
not say whether the predicted 1 percent ozone loss was actually
occurring or not (the natural variation is 2 - 3 percent), the
2
implications of this growing understanding sounded a call for new
action. That call was answered with an unprecedented recent
international accord regarding these compounds.
B. The 1987 Montreal Protocol
On Wednesday, 16 September 1987, the United Nations adopted
the "Montreal Protocol on Substances That Deplete the Ozone
Layer". The contracting parties were required to take specific
actions regarding certain man-made chlorine- and bromine-
containing chemicals, i.e., the CFCs and halons.
In short, the Protocol required (1) an early freeze on the
usage of several CFCs, (2) a phased reduction in their production
that leads to an eventual 50 percent decrease by the year 2000,
and (3) a freeze (later than that of the CFCs) on the production
of halons. These features of the Protocol reflect the scientific
understanding of how chlorine and bromine influences
stratospheric ozone:
O
CFCs. From a scientific perspective, any regulatory policy
should consider all of the fully halogenated chlorine-
containing compounds, which are characterized by high Ozone
Depleting Potentials (ODPs), as a group for the purposes of
regulation. The Montreal Protocol did indeed include the
major CFCs in its chemical scope.
Halons. Bromine compounds are about ten more effective than
chlorine in destroying ozone, as reflected by their high
ODPs. The Montreal Protocol also included the major halons
in its chemical scope.
Long Equilibrium Times. The CFCs and halons have long
atmospheric residence times; therefore, their stratospheric
abundances would continue to grow for many decades, even if
their emissions were to plateau or be reduced. Hence, from
3
the standpoint of limiting the maximum concentrations of
chlorine and bromine in the stratosphere, emission reductions
done earlier need not be as severe as those done much later.
This is consistent with the Montreal Protocol's attempt to
get a freeze on emissions as early as possible.
The Montreal Protocol was extremely important step forward in
the ozone/chlorine-science/policy issue. It was both a specific
start and a malleable document. With regard to the latter, the
Protocol requires that its provisions be revisited periodically
for adequacy in light of new scientific and technical knowledge.
To provide that input, the Protocol established the preparation
of periodic scientific and technical reports, sponsored by the
United Nations Environment Programme and the World Meteorological
Organization.
The first of these reports, "Scientific Assessment of
Stratospheric Ozone: 1989" was the product of an international
group of over 100 scientists. It focused on the new advances
that had occurred since the Montreal Protocol was crafted,
namely, the discoveries made since 1986. The period 1986 - 1990
proved to be an extremely fruitful one regarding our
understanding of the ozone layer.
C. Stratosphere Ozone: 1986 - 1990
(1) Research Efforts
There were four principal efforts that focused on making
major advances in the understanding of stratospheric ozone:
4
International Ozone Trends Panel: 1988. During 1987 and
early in 1988, an international group of ozone researchers
re-examined all of the existing ozone trends data, examined
these improved data sets for systematic ozone trends, and
compared those trends to those predicted for natural (e.g.,
solar variations) and man-made (e.g., CFCs) causes.
Antarctic Ozone Campaigns: 1986 - 1987. While the Antarctic
ozone "hole" had been discovered at the time the Montreal
Protocol was being prepared, the cause of this dramatic
seasonal ozone depletion in the Antarctic stratosphere was
not then known. Indeed, theories were proposing at that
time a variety of possible causes, ranging from natural to
man-made influences. To address this remarkable phenomena,
the National Ozone Expeditions I and II took instruments to
McMurdo Station in Antarctica to observe the ozone changes
in 1986 and 1987. In addition, the Airborne Antarctic Ozone
Experiment used high-flying research aircraft from a base at
Cape Horn to probe the stratosphere over Antarctica.
Arctic Ozone Campaigns: 1988/89. Although no "hole"
comparable to that over Antarctica had been identified over
the Arctic, the findings from the Antarctic expeditions
posed questions about the northern regions that required
addressing. This was done in 1988 with limited aircraft
flights to Alaska and ground-based measurements from
Greenland. These were followed by a large-scale aircraft
campaign, the Airborne Arctic Stratosphere Experiment,
which was based out of Norway in the winter of 1989/90.
Laboratory Studies of Chemistry on Particles. Most
atmospheric studies had focussed on chemical reactions
between gases. Reactions that occur on surfaces were much
more difficult to examine. Yet, the recognition of the
potential importance of such surface-enhanced reactions was
growing. Innovative laboratory methods were developed and
greatly expanded the information available.
These "ozone years" have been the most intensive period of
ozone research to date. Thanks to the prodigious efforts of a
large fraction of the ozone research community, the results have
been phenomenal. They have changed our view of the stratosphere
and have set stratospheric research on to a new course.
5
(2) Major Findings
There were four major findings from this period regarding
the impact of human activities on the Earth's protective ozone
layer. Each heightened the concern that chlorine- and
bromine-containing chemicals can lead to a significant depletion
of stratospheric ozone:
Cause of the Antarctic Ozone "Hole". Scientists concluded
that chlorinated (largely man-made) and brominated chemicals
are primarily responsible for the decreases of stratospheric
ozone over Antarctica in springtime. The ozone loss is
accelerated in this region in comparison to elsewhere by
chemical reactions that occur on the surfaces of polar
stratospheric clouds that shift the chlorine compounds into
a more reactive form.
Long-Term Global Ozone Decreases. The re-analysis of data
from ground-based ozone networks show downward trends that
cannot be accounted for by any known natural causes.
Specifically, after accounting for solar variation and
systematic atmospheric-circulation effects, these ground-
based data showed downward trends from 1969 to 1988 of 3 - 5
percent (i.e., 1.8 - 2.7 percent per decade) in the northern
hemisphere (30 - 64 {N latitudes) in the winter months. This
decrease is larger by factors of two to three than the
chlorine-induced decreases predicted by our current
theoretical models. The cause of this decrease is one of
the most important remaining questions in stratospheric
ozone research.
Perturbed Arctic Chemistry. The 1989 expedition to Norway
demonstrated that enhancements of ozone-depleting chlorine
species also occur in the Arctic stratosphere. Thus, at the
end of the winter night, the Arctic is "primed" for ozone
loss. Whether ozone destruction occurs with the arrival of
sunlight depends on whether the Arctic is warming (no loss)
or remains cold and isolated (ozone loss) for a period of
weeks (as the Antarctic routinely does). Therefore, the
degree of any future Arctic ozone depletion will depend on
the particular meteorology of each Arctic winter, as well as
the future increases in chlorine and bromine abundances.
6
Surface-Enhanced Chemical Processes. Laboratory studies
demonstrated that the reactions on the surfaces of ice
particles, as well as on those of the background particles
in the global stratosphere, were fast and could shift
chlorine compounds to a more reactive form.
(3) Implications
The results from the ozone research over these years had
several major implications as input to public policy decisions
regarding restrictions on man-made substances that lead to
stratospheric ozone depletion:
Observed CFC-Induced Ozone Losses. The scientific basis for
the 1987 Montreal Protocol was the theoretical prediction
that, should CFC and halon emissions continue to grow, there
would eventually be substantial ozone depletion. Recent
research has demonstrated that actual ozone loss due to the
CFCs has already occurred, i.e., the Antarctic ozone
"hole ", albeit in a unexpected place and fashion.
Continuing Predictions of Future Ozone Losses. Even if the
control measures of the 1987 Montreal Protocol were to be
implemented by all nations, today's atmospheric abundance of
chlorine of about 3 ppb (parts chlorine in a billion parts
of air) would still at least double to triple during the
next century, yielding large predicted ozone losses.
Potentially Underestimated Ozone Losses. The fact that the
downward ozone trends up to 1988 from the ground-based data
at mid-latitudes were larger than those predicted for that
time has led to the speculation that the models do not
contain all important ozone-losses processes. The
speculations were twofold: The surface chemistry that
causes the ozone depletion in Antarctica due to the presence
of polar stratospheric clouds could be occurring on the
background layer of particles naturally present in the
stratosphere. Furthermore, the poles could be acting as
"chemical processors" that could be influencing the
atmosphere well outside of polar regions. Hence, future
global ozone depletions could well be larger than originally
predicted, if such processes were significant and if models
could correctly incorporate them.
7
Eliminating the Antarctic ozone "hole". Large-scale ozone
depletions in Antarctica appear to have started in the late
1970s and were initiated by atmospheric chlorine abundances
of about 2 ppb, compared to today's level of about 3 ppb.
Therefore, to return the Antarctic ozone layer to levels
approaching its natural state, one of the limited number of
approaches available is a complete phase out of all long-
lived CFCs, halons, and carbon tetrachloride, as well as
careful considerations of the shorter-lived compounds such
as methyl chloroform and the CFC replacements. Otherwise,
the Antarctic ozone "hole" is expected to remain
indefinitely, assuming that the present meteorological
conditions continue. For example, it is estimated that the
earliest that the Antarctic ozone "hole" could be "repaired"
is roughly the year 2075. This estimate would require that
(1) the above long-lived compounds would be phased out as
early as possible and, (2) the shorter-lived compounds would
be phased out in time for the atmospheric processes to purge
them from the atmosphere by 2075.
D. The 1990 London Amendments to the Montreal Protocol
Based on these findings and their implications, the
contracting parties to the Montreal Protocol chose to strengthen
its provisions substantially when they met in London during the
summer of 1990. The high points of those new provisions are the
following:
CFC elimination. A faster step-wise reduction in
production, leading to a complete phaseout of the CFCs by
the year 2000.
Halon elimination. A faster step-wise reduction in
production, leading to a phaseout by the year 2000, except
for essential uses.
Inclusion and elimination of other substances. A step-wise
reduction, leading to a phaseout of carbon tertrachloride
and methyl chloroform by the years 2000 and 2005,
respectively.
Several chemical compounds that have lower ODPs and
relatively short atmospheric residence times may have significant
value as CFC replacements. These compounds are not excluded
8
under the London Amendments, but are identified as "transitional
substances". The label implies that they will be closely
scrutinized with regard to their ODPs, as well as their other
possible environmental effects, such as contributions to the
"greenhouse" issue.
The U.S. Clean Air Act Amendments of 1990 included a section
on stratospheric ozone protection. It requires generally the
same type of reductions as the amended Montreal Protocol, but
also puts "sunset" dates on the CFC and halon replacements,
depending on their ODPs.
E.
Remaining Scientific Questions
While the ozone research of the past few years has provided
remarkable results on which amendments to the Montreal Protocol
and the Clean Air Act were crafted, it would be incorrect to
imply that we understand all that we need to. Even with the most
stringent and economically painful efforts:
(1) the chlorine abundance in the stratosphere will still reach
perhaps 4 - 5 ppb by the turn of the century,
(2) that peak abundance could persist if the CFC replacements
are widely used, rather than phased out globally,
(3) the chlorine abundance will not drop to the 2 ppb required
to eliminate the Antarctic ozone "hole" for about 75 years,
and
(4) the return to natural levels lies centuries away.
9
Should we be worried about this state of affairs, or does
the fact that we have reduced emissions mean that there is no
reason to continue to pose questions? Two observations are
relevant:
We have created a new global feature, the Antarctic ozone
"hole", that will be with us for about a century. While we
think we know how we did it, we cannot yet forecast the
consequences of our creation. There are several open
questions:
-
What does a century of seasonal ozone losses imply for
the effects of ultraviolet radiation on Antarctic fauna?
-
What are the climatological implications (temperature
and circulation patterns)?
-
Does the ozone "hole" leak, i.e., what are the
implications for nearby countries like New Zealand?
-
With ozone loss linked to stratospheric ice particles
(and hence temperature and climate), what does the
climate variation of the next century imply for ozone
loss?
The peak chlorine levels of 4 - 6 ppb will persist for at
least a decade. We were caught unaware by the appearance of
the Antarctic ozone hole at about 2 ppb some years ago. How
confident are we that there are no surprises in store in the
3 - 6 ppb range?
-
What will be the amount and frequency of springtime
ozone loss in the Arctic?
-
What will be the effect of midlatitude aerosols on
global ozone loss?
-
How well do we understand the Ozone Depletion Potentials
of the CFC replacements and the Halons?
As the dialogue between science and policy heightens
regarding the 1992 reassessment of the adequacy of the Montreal
Protocol Amendments and the implementation of the Clean Air Act
Amendments, policy will rightly ask science for the answers to
10
these questions. These answers will require a better fundamental
understanding of, for example, the couplings of meteorology and
chemistry, which is a challenging task.
Nevertheless, the fundamental understanding of natural
processes that relate to the well-being of markind are almost
always cost-effective. For example, comparison of the cost of a
Salk/Sabin vaccine for polio to the economic and human costs of
life in an iron lung teaches us what can be achieved when the
cause of a thing is truly understood. Regarding our environment
and what it means to us all, it is the price of ignorance that we
cannot afford.
Mr. Chairman, this concludes my prepared remarks. I would
be pleased to answer any questions that you or the members of the
Subcommittee may have.
11