A Quarterly Publication of Zephyr Environmental Corporation | JANUARY 2015
O
Whatever Happened to the Ozone Hole?
zone in the air we breathe is a hot topic
for environmental regulators today. Just
last month, EPA proposed another round
of tightening of the National Ambient Air Quality
Standards for ozone. However, three decades earlier,
the world’s attention was drawn to the blanket of
ozone trapped in the portion of the atmosphere
between 30,000 and 50,000 feet above the earth’s
surface known as the stratosphere. This layer of
ozone protects the earth from the sun’s ultraviolet
(UV) radiation — a type of radiation that, in excess,
increases the incidence of skin cancer and cataracts,
reduces crop yields, and disrupts the marine food
chain by destroying plankton in the ocean. And
scientists had found a hole in the ozone layer.
Ozone is destroyed by certain chlorine- and brominecontaining chemicals, which are used as refrigerants,
pesticides, solvents, and fire extinguishers. While
most of these substances, referred to as ozone depleting substances (ODSs), are extremely stable in the
lower atmosphere, after they reach the stratosphere,
the sun’s UV radiation causes them to release chlorine
and bromine atoms which react, in turn, to destroy
the ozone. One chlorine atom can destroy 100,000
ozone molecules, and bromine atoms are even more
destructive than chlorine atoms.
In 1976, the United States Academy of Sciences
linked the release of ODSs to ozone depletion, and
subsequent studies confirmed this relationship. In
response, representatives from 24 countries signed
the 1987 Montreal Protocol on Substances that
Deplete the Ozone Layer, agreeing to start phasing
out the manufacturing of ODSs in 1989. The treaty
has been amended several times, and today more
than 190 countries have ratified it. In a 2014 article
celebrating the 25th anniversary of implementing
the Montreal Protocol, the Associated Press acclaimed the treaty “one of the great success stories
of international collective action in addressing a
c o n s u l t i n g
u
global environmental change phenomenon.” But
before trumpeting the Montreal Protocol as a ‘great
success story,’ it’s important to look at the facts. Has
the treaty actually accomplished what it set out to do?
The National Aeronautics and Space Administration (NASA) and the National Oceanic and Atmospheric Administration (NOAA) have monitored
the ozone layer and stratospheric concentrations
of ODSs since the 1970s. However, concerns were
not raised until the 1980s, when measurements first
showed a significant reduction in the ozone layer during September and October, giving the appearance
of a hole over Antarctica — a phenomenon that was
later observed over the Arctic. Even with reductions
in ODSs under the Montreal Protocol, the situation
didn’t immediately improve. From a size over 3.3 million square kilometers in 1980, NASA and NOAA
measurements showed that the ozone hole grew by
900 percent to a peak area of 29.9 million square
kilometers by 2000. In the last 15 years, the size of
t r a i n i n g
ozone hole >>> continued on page 8
u
d a t a
s y s t e m s
FROM THE TRENCHES
We’re Going on a Toad Hunt
S
ometimes you get more than you bargain for. That was
the case when Zephyr was awarded a project to obtain the
environmental permits for a new crude oil pipeline in Texas.
The project began with conducting the usual environmental
constraints analysis, followed by an extensive field survey of the
entire 450 miles of the proposed right-of-way (ROW). We soon
discovered the ROW would pass right through the potential
habitat of a federally endangered species, the Houston toad.
We met several times with the client to discuss whether the
pipeline could be re-routed around the habitat, or if we could go
under it, or if we could go over it, or if we must go through it. It
reminded me of a game I played as a child with my grandmother
called “We are going on a bear hunt.” Her answer always seemed
to be “we must go through it.” As it turns out this project was no
different; we had to go through it.
Zephyr has considerable experience in assessing threatened or
endangered species habitat, but this project was unlike anything
that had been attempted within Houston toad habitat. Years ago, a
Houston toad had actually been heard at a nearby pond, but there
were no visual sightings to confirm that the toad occupied the
woods and ponds of Robertson County adjacent to the proposed
ROW. Therefore, we had to choose one of two options: A) assume
that the project area was occupied by the Houston toad and
prepare to mitigate the project’s impacts on the species habitat, or
B) conduct up to three years of surveys to verify whether the toad
actually occupied the area. This was a pivotal choice; if we selected
option B) our client would not be able to meet the aggressive
project schedule. As we considered our options, we consulted
with the Houston toad species expert (yes, the Houston toad has
a species expert). As expected, he first asked “Can’t you go around
it?” But after our explanation, he suggested that we assume that
the habitat is occupied by the toad. Then we knew “we must go
through it!”
Following the expert’s guidance, we began to identify conservation
measures to minimize or avoid impacts to the Houston toad and
its potential habitat. The mitigation plan based on these measures
was submitted to the U.S. Fish and Wildlife (USFWS) and, with
some modification, it was approved. Then the real fun began!
Our first task was to begin surveys to determine whether the toad
still called the area woodlands home. These surveys, conducted
at night when conditions were favorable for breeding, consisted
of two trained biologists driving to pre-selected spots along roads
adjacent to ponds or water features. You may be thinking that it
would be hard to see a toad at night from a road — and you’re
right. But it’s much easier to hear a toad than see one! When
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Photo credit: John T. Williams
atmospheric conditions are just right the male Houston toad does
what most all other toads do, he searches for a mate. He finds the
nearest pond and does his best to let every female within earshot
know he’s there. The “chorusing” of a Houston toad distinguishes
it from all other toads and frogs — its call is described as a high,
clear trill that lasts an average of 14 seconds. So imagine yourself,
standing along the road at night near a pond, straining to pick
out the call of the rare and endangered Houston toad from the
cacophony of frogs and toads and crickets. It’s actually quite
enjoyable.
Most nights we heard many toads and frogs common to the
southeastern U.S. Then, on one especially warm and muggy night,
from the edge of a road in Robertson County, the call of a lone
Houston toad rang out! On that particular night, two project
biologists and two representatives of the USFWS were present.
The sound was coming not from some distant pond, but from under
our very feet! We froze and waited. Waited a long time. Then we
heard it again, and there, hidden in the tall grass, was a beautiful
specimen of a male Houston toad! So it was confirmed that night
that the Houston toad did indeed call Robertson County home.
This story has more than one happy ending. Our client was pleased
that we had made it possible to complete the pipeline project on
time and within our budget. The USFWS was happy because it
was possible to construct the pipeline without the “take” of one
Houston toad and pleased that a new population of Houston toads
had been documented outside Bastrop County. Regarding the
Houston toad, he probably would have preferred that we had gone
on a “real bear hunt.” Z
Steve McVey, PG
Principal
AN ATTORNEY’S PERSPECTIVE
The Daubert Standard and “Abuse of Discretion”
I
n 1993, the U.S. Supreme Court instructed federal district
judges to act as “gatekeepers” to ensure that expert witness
testimony is both relevant and reliable before it is presented to
a jury. The goal of the Supreme Court in the landmark Daubert
decision was to keep so-called “junk science” out of the courtroom.
In the aftermath of the decision, most states, including Texas,
adopted the standard and even some states that did not formally
do so have, nevertheless, encouraged trial judges to act as gatekeepers, albeit under the slightly different Frye standard.
Prior to Daubert, the focus was almost exclusively on an expert’s
qualifications, not the expert’s methodology. Essentially, if the
trial court found the expert qualified, the expert was free to testify
about practically anything, no matter how unreliable, so long
as it was within the expert’s field. For example, in the litigation
from which Daubert arose, medical causation experts (doctors
and epidemiologists) testified that Bendectin, a widely prescribed
drug for morning sickness, caused birth defects. There was only
one problem: over 30 studies comparing the rates of birth defects
in women who took Bendectin to the rates in women who didn’t
found that the rates were similar in both groups. Indeed, not a
single controlled study showed a statistically significant increased
risk, but this did not deter the experts hired by Bendectin plaintiffs from attributing birth defects to Bendectin.
In Daubert, the Supreme Court outlined four non-exclusive
factors relating to the expert witness’s methodology to be considered by district courts in exercising their gatekeeping duties:
(1) whether the expert’s theory or technique can be and has
been tested, (2) whether it has been subjected to publication in
the peer-reviewed literature, (3) the known or potential rate of
error associated with the theory or technique, and (4) the degree to
which it is generally accepted as reliable by the relevant scientific
community. This last factor relating to general acceptance is the
Frye standard that Daubert replaced.
Daubert essentially ended the Bendectin litigation because courts
found that it is not reliable to opine as to medical causation in
the face of an overwhelming body of controlled studies refuting
the causation hypothesis. Similarly, application of the Daubert
standard ultimately ended litigation relating to the theory that
silicone breast implants cause autoimmune diseases. In 1992, the
FDA announced a moratorium on silicone breast implants in
response to safety concerns, and tens of thousands of women sued.
As was true in the Bendectin context, more than 25 controlled
studies demonstrated that the rate of autoimmune disease was
similar in both implanted and non-implanted women. Eventually,
courts in both Daubert and non-Daubert jurisdictions began
excluding the expert witnesses for the breast implant plaintiffs
and the FDA ultimately concluded that silicone breast implants
are safe and effective.
Has all of this gatekeeping by trial judges resulted in a decrease in
junk science in the courtroom? Although there is little empirical
research on the topic, the likelihood that an expert opinion will
be excluded as scientifically unreliable has increased significantly
in the years since Daubert (in both Daubert and non-Daubert
jurisdictions). And junk science in the courtroom is still alive
and well — the likelihood that an expert will get excluded
remains small. All kinds of claims with little scientific basis
continue to be litigated in both Daubert and non-Daubert
jurisdictions. For example, cases involving various types of air,
ground, and/or water emissions have been allowed to go forward
even where there is no dispute that the emissions did not violate
any regulatory health based standard.
How can this be? Three words: abuse of discretion. This is the
standard appellate courts use when reviewing a trial court’s
decision relating to the admission or exclusion of expert testimony.
Trial judges have a great deal of discretion in determining whether
an expert’s methodology passes muster under Daubert. The vast
majority of appeals involving both the admission and exclusion
of expert evidence under Daubert affirm the decision of the trial
court. For example, one federal court of appeals affirmed one trial
judge who admitted the breast implant causation evidence even
though the very same court of appeals had previously affirmed
a different trial judge’s exclusion of essentially the very same
evidence. Accordingly, perhaps the most important question a
litigant can ask with respect to whether a Daubert challenge will
be granted or denied is the following: who is the judge? Z
David P. Herrick, Esq.
Herrick and Associates PC
3
News Briefs
national news
EPA Proposes More Stringent Ozone Standard
On December 17, the U.S. Environmental Protection
Agency (EPA) proposed to lower the national ambient
air quality standards (NAAQS) level for ozone (O3)
to 65-70 ppb. However, EPA isn’t ruling out retaining
the current 75-ppb level and is accepting comments
by March 17, 2015 on an even lower 60-ppb standard.
The proposal also addresses implementation timing
and procedures, extending the O3 monitoring season,
and changes to monitoring requirements. Under a
separate rulemaking, EPA is considering revising how
it determines whether a source causes or contributes to
a violation of the NAAQS. EPA is under a court order
to make a final O3 NAAQS determination by October
1, 2015. For more information, contact Lucy Fraiser at
512.879.6652 or [email protected].
CO2 Emissions from Electric Power Generation
Trend Downward
According to an October Energy Information Administration report, U.S. energy-related carbon dioxide
(CO2) emissions have decreased in five of the past eight
years. Notably, 2013 power plant CO2 emissions were
about 15 percent lower than 2005 levels, mainly due to
lower than expected electricity demand, replacement
of coal- and oil-fired generation with natural gas-fired
units, and increased use of renewable energy sources
such as wind and solar power. Despite the overall 8-year
trend, market conditions in 2013 and 2014 have made
coal generation more economically attractive, leading to a small rise in power sector CO2 emissions. For
more information, contact Lou Corio at 410.312.7912
or [email protected].
OSHA Seeks Input on Managing Chemical
Exposures in the Workplace
On October 10, the Occupational Safety and Health
Administration (OSHA) requested stakeholder input
on best approaches and strategies for regulating chemicals in the workplace. In its evaluation of procedures
for reducing and controlling exposures to workplace
chemicals, OSHA is considering updating permissible
exposure limits. Public input must be received by April
8, 2015. For more information, contact Molly McKenna
at 512.579.3837 or [email protected].
EPA Makes Preliminary Determination to
Regulate Strontium in Drinking Water
On October 20, EPA made a preliminary determination to regulate strontium in drinking water due
to the potential adverse health effects of this chemical — at elevated levels, strontium can weaken bones
in persons who are calcium deficient. EPA intends to
decide in 2015 whether to move forward with rulemaking. For more information, contact Miranda Briones
at 512.879.3957 or [email protected].
Final EPA Climate Change Adaptation
Plan Released
On October 31, the White House released the final
version of EPA’s Climate Change Adaptation Plan — a
document identifying how EPA’s mission is vulnerable
to climate change and describing planning EPA needs
to conduct to ensure it will be able to continue to fulfill
its mission in the face of climate change. Vulnerabilities
identified include, among other things, impacts of
changing precipitation patterns on long-term water
infrastructure, impacts of more intense weather events
on disaster response, and climate change impacts on
ozone air quality. The plan was prepared in response
to a 2013 presidential executive order that federal
agencies develop plans to adapt their programs to the
effects of climate change. For more information, contact
Lou Corio at 410.312.7912 or [email protected].
4
Court Lifts Stay on Cross-State Air Pollution Rule
On October 23, the D.C. Circuit Court of Appeals
ordered that its 2011 stay of EPA’s Cross-State Air
Pollution Rule (CSAPR) be lifted — an action
consistent with the Supreme Court’s April 2014
decision upholding CSAPR (see July 2014 issue of
Currents). In response to the latest ruling, EPA, on
November 21, amended the dates by which CSAPR
emissions budgets must be implemented, pushing
forward the first phase of emissions reductions to
2015 and 2016 and the second phase to 2017 and
beyond. Other amended deadlines include those for 1)
monitoring system certification, 2) emissions reporting
and allocation, 3) emissions allowances recording,
4) revision of state implementation plans (SIPs), and
5) sunsetting of the Clean Air Interstate Rule (CAIR).
In a parallel December 3 action, EPA provided notice
of revised emissions allowances allocations to existing
generating units. For more information, contact Roger Brower
at 410.312.7907 or [email protected].
state news
EPA Approves GHG Permitting Program in Texas
In two actions on November 10, EPA formally handed over
authority of the Texas greenhouse gas (GHG) Prevention of
Significant Deterioration (PSD) permitting program to the
Texas Commission on Environmental Quality (TCEQ). In the
first action, EPA approved the revisions to the state’s GHG PSD
permitting rules, and, in the second, EPA withdrew the federal
implementation plan (FIP) that had previously established EPA
as the Texas GHG permitting authority. The TCEQ has updated
its new source review air quality permit application Form PI-1 to
accommodate GHG permitting. For more information, contact
Eric Quiat at 512.579.3823 or [email protected].
TCEQ Kicks-Off Expedited Air Quality Permitting
On November 13, the TCEQ issued rules providing for expediting
air quality permit reviews (see July 2014 issue of Currents). Under
the new rules, the TCEQ may, subject to the availability of agency
resources, expedite the review of applications for permits by rule,
new source review and standard permits, and Title V permits if
applicants can demonstrate the projects will “benefit the economy
of this state or an area of this state.” To expedite an application, the applicant must submit the new Expedited Permitting
Request Form APD-EXP and pay a surcharge sufficient to cover
the expenses incurred by the TCEQ in expediting the review. For
more information, contact Kristin Parsons at 512.579.3842 or
[email protected].
EPA Proposes Reductions in Haze-Forming Emissions
from Texas Power Plants
On December 16, EPA proposed to partially approve and partially disapprove the Texas plan for protecting visibility in national
parks and wilderness areas from the effects of haze-forming
pollutants emitted in Texas. To remedy shortcomings identified
in the plan, EPA proposed a FIP that sets emission limits for 15
of the state’s coal-fired electric generating units. The FIP would
rely on sulfur dioxide scrubber retrofits or upgrades on the affected
units but would not mandate particular technologies. Sources
requiring scrubber retrofits would have five years to meet the new
emission limits, and sources that require only scrubber upgrades
would have three years. For more information, contact Bob
Breeze at 512.879.3671 or [email protected].
TCEQ Continues to Seek Input in Developing TPDES
Temperature Screening Procedures
The TCEQ will continue to host meetings through March
2015 seeking stakeholder input on Texas Pollutant Discharge
Elimination System (TPDES) permitting screening for potential
compliance of industrial wastewater thermal discharges with
receiving water temperature limits. Until EPA approves the
TCEQ’s thermal discharge evaluation procedures, it will accept
the use of interim TPDES permit conditions, which require
that an applicant develop a plan to characterize the thermal
plume resulting from industrial wastewater discharges that have
temperature as a contaminant. For more information, contact
Dave Sorrells at 512.879.6626 or [email protected].
Maryland Study Concludes Fracking Can
Be Safely Managed
In a November report, the Maryland Department of the
Environment (MDE) and the Maryland Department of Natural
Resources (DNR) concluded that natural gas production from
the Marcellus Shale via hydraulic fracturing (fracking) can be
managed without unacceptable risks to public health, safety,
the environment, and natural resources, provided that all
recommended best practices are followed and that the state is
able to rigorously monitor and enforce compliance. Best practices include applicant development and state approval of a
mandatory comprehensive gas development plan and applicant
submittal of an environmental assessment as a condition of
receiving a drilling permit. The Maryland portion of the Marcellus
Shale formation underlies only Garrett and Allegany Counties.
For more information, contact Lou Corio at 410.312.7912 or
[email protected].
TCEQ Proposes to Lift Penalty Fees for Failure
to Comply with Old Ozone Standard
On November 19, the TCEQ proposed to revise its existing ozone
NAAQS compliance agreement with EPA to remove obligatory
penalty fees assessed on sources in the Houston-GalvestonBrazoria (HGB) area for failure of the area to meet a November
2007 deadline to comply with the 1979 one-hour ozone NAAQS
— a standard that was revoked in 2005. The TCEQ proposed
revision anticipates EPA’s mid-2015 passage of rules that would
provide a mechanism for a state to lift such obligations. To qualify
for the lifting of penalty fees under the mechanism proposed by
EPA, the TCEQ would be required to demonstrate that the area
is now and will remain in attainment with the revoked standard
for the next 10 years. For more information, contact Curtis
Harder at 512.879.6643 or [email protected].
Pennsylvania Revises Ozone Precursor Emissions
Limits for Existing Major Sources
In November, the Pennsylvania Department of Environmental
Protection (PADEP) revised its Reasonably Available Control
Technology (RACT2) rules for controlling emissions of ozone
precursors (nitrogen oxides and volatile organic compounds) from
news briefs >>> continued on page 6
5
news briefs >>> continued from page 5
existing major sources. The affected source categories include
electric generating units, combustion units, and cement kilns.
Under the rule changes, presumptive emission limits for
combined-cycle and larger simple-cycle combustion turbines
have been relaxed, facilities that need to install controls to
meet either the presumptive or approved alternative limits may
petition PADEP for up to a 3-year extension of compliance with
the limits, and the facility-wide or system-wide nitrogen oxide
(NOx) emission averaging scheme for meeting RACT limits has
been modified — a change that will benefit sources that need to
average. PADEP estimates that with the implementation of the
final RACT 2 rules, NOx emissions will be reduced by 42 percent
compared to current RACT allowable emissions. The final rule
is expected to go into effect by mid-2015. For more information,
contact Lou Corio at 410.312.7912 or [email protected].
TCEQ Removes Benzene and Hydrogen Sulfide
from the Texas City Watch List
On November 13, the TCEQ finalized the removal of benzene and
hydrogen sulfide from the Texas City Air Pollution Watch List
(APWL) area (see October 2013 issue of Currents). Texas City,
however, remains on the APWL for propionaldehyde. TCEQ will
post a revised APWL map and additional information regarding
the delisting on its website. For more information, contact Jill
Parkes at 512.579.3836 or [email protected].
Maryland Proposes Historical Hazardous Substance
Release Reporting Rule
On October 31, the MDE proposed to change to its hazardous
substance response plan rules to require reporting of previously
unreported information regarding past hazardous substance
releases. A person who possesses a sample result or other
environmental assessment that indicates the presence of a released
hazardous substance at or above an MDE clean-up standard
would be required to report the information to the MDE.
Information of this kind is commonly generated during property
acquisitions, site investigations, and routine operations, and is
not always shared with the MDE. For more information, contact
David Mahler at 410.312.7909 or [email protected].
Foundation Announces $13.2 Million for Gulf
Restoration Projects in Texas
On November 17, the National Fish and Wildlife Foundation
announced roughly $13.2 million in grants of criminal settlement
funds from the Deepwater Horizon oil spill litigation to finance
6
expansion of wildlife refuges, restoration of threatened habitat,
and protection of habitat from erosion along the Texas Gulf
Coast. These projects are designed to remedy harm or reduce
the risk of future impacts to natural resources impacted by the
2010 spill. The $13.2 million grant is only a small portion of the
$203 million to be allocated over a 5-year period for the state of
Texas. For more information, contact Bob Fisher at 281.668.7349
or [email protected].
TCEQ Considers Changes to Evaporation Pond
General Permit
In March 2014, the TCEQ issued a new general permit to
authorize the disposal of wastewater by evaporation from surface
impoundments adjacent to waters of the state. With this issuance, all wastewater evaporation ponds must be authorized
either under the general permit or another permitting mechanism. The TCEQ is considering changes to the general permit
to allow certain existing evaporation ponds that previously had
obtained a Texas Land Application Permit or had provided
notice to the TCEQ in accordance with 30 TAC §335.2(d)
and §335.6 that was acknowledged in writing, prior to the
effective date of this general permit amendment. Following a
December 11 stakeholders meeting, the TCEQ is considering
whether conditionally exempt small quantity generators that
use evaporation ponds were required to notify the TCEQ under
§335.6 and receive written acknowledgement of the ponds. The
TCEQ is requesting stakeholder input on the proposed general
permit changes. For more information, contact Betty Moore at
512.879.6622 or [email protected].
Fifth Circuit Denies Request to Reopen
Whooping Crane Case
On December 15, the Fifth Circuit of Appeals denied a petition
by plaintiffs to reopen the issue of whether the TCEQ failed to
manage the waters of the Guadalupe River, resulting in the death
of endangered whooping cranes in 2008 (see April 2013 issue
of Currents). The Court’s December decision upholds a June 30
decision of a panel of this court reversing the 2013 decision of
the Corpus Christi District Court to enjoin the TCEQ from
issuing permits to withdraw water that flows to the estuary where
the whooping cranes spend the winter The plaintiffs in the case
have 90 days to file an appeal with the U.S. Supreme Court. For
more information, contact Clay V. Fischer at 512.879.6629 or
[email protected]. Z
FROM THE PRESIDENT
Is it Time for a New Green Revolution?
T
he “green revolution” was a seminal development in the
history of humanity. It commonly refers to a series of
research, development, and technology transfer initiatives that
occurred between the 1940s and the late 1960s, in which global
agricultural production increased dramatically. The initiative
is credited with saving over a billion people in the developing
world from starvation and has led to food security for most of the
world. One net result is that our planet is sustaining over seven
billion human lives, with all the creative energy and demand
for resources that implies.
But agricultural researchers are very concerned as to whether our
current agricultural practices are sustainable. As noted in the
December 2014 issue of Scientific American, it takes 1,000 years
to generate three centimeters of topsoil. According to a senior
UN official, at current rates of degradation the world’s topsoil
could be gone within 60 years (nearly a third of the world’s topsoil
has already been degraded). The causes of soil degradation include
chemical-heavy farming techniques, deforestation which causes
erosion, and global warming.
An official with the Food Agricultural Organization said that
unless new approaches are adopted, the global amount of arable
and productive land per person in 2050 will be only a quarter of
the 1960 area. This is hugely problematic considering ninetyfive percent of our food comes from the soil. No comprehensive
solutions are apparent, although organic farming proponents
suggest that organic farming could be a big part of the solution. Z
I would like to add a quick note to announce Zephyr’s new office in
York, Pennsylvania. Our team of qualified consultants in York will
appreciably add to our ability to deliver our Mid-Atlantic clients
all of the services Zephyr provides. More information can be found
on our website at www.zephyrenv.com.
Joe Zupan
President
Zephyr is a full-service environmental, health, and safety firm offering consulting, training, and data systems services to clients worldwide. We specialize in air and water quality, waste management and cleanup issues, incident management, natural resources, and workplace and community safety.
Currents is published quarterly by Zephyr Environmental Corporation, is edited by David Cabe of Cabe Environmental Solutions, and designed by Allen Griffith of Eye 4 Design. Current and
past issues of this newsletter are available at our website. For more information about Currents, or to add your name to our subscription list, please email: [email protected] or visit
www.zephyrenv.com.
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ozone hole >>> continued from page 1
the ozone hole has not shown any real trends, varying
from 29.6 million square kilometers in 2006 to 21.1 million square kilometers in 2012, with little change in the
past two years. These trends are generally corroborated
by the World Meteorological Organization (WMO)
and the United Nations (UN), who reported in their
Twenty Questions and Answers about the Ozone Layer:
2010 Update that stratospheric ozone declined over
most of the planet during the 1980s and early 1990s,
and has remained relatively unchanged since 2000.
The trends in levels of stratospheric ozone since 1989
beg the question: why is the ozone hole today bigger
than it was before Montreal Protocol ODS emissions
reductions began? According to the WMO/UN report,
total annual emissions of ODSs, on a basis weighted by
their potential to destroy ozone, steadily increased until
1990 and then began decreasing. However, the ozone
hole continued to grow for another 10 years, maxing
out in 2000 at 29.9 million square miles. The WMO/
UN report states that by 2010, emissions of ODSs had
dropped to one-third of their 1990 levels and that measured stratospheric concentrations of chlorine- and
bromine-containing substances originating from ODSs
had finally started to decline, but by only about 10 to
15 percent from their peak values 10 to 15 years earlier.
The WMO and the UN concluded that “actions taken
under the Montreal Protocol . . . are enabling the return
of the ozone layer toward 1980 levels.”
A December 11, 2013 press release by NASA’s Goddard
Space Flight Center is more cautious about the effec-
tiveness of ODS bans on the restoration of stratospheric ozone. According to NASA, “We are still in
the period where small changes in chlorine do not
affect the area of the ozone hole, which is why it’s too
soon to say that the ozone hole is recovering.” In one
study, NASA evaluated the ozone holes of 2006 and
2011, two of the largest in the past decade, and was
surprised to find that they contained different amounts
of ozone-depleting chlorine. Using a model designed to
simulate the influence of chemical and meteorological
factors, scientists simulated the effects on stratospheric
ozone levels of “turning off” ozone-destroying chemical
reactions. From this modeling, NASA concluded that
until chlorine levels in the lower stratosphere decline
below the early 1990s level (expected by 2030), wind
patterns and temperature, not the levels of ozonedepleting chlorine, will dictate the variable area of the
hole in any given year, and that stratospheric ozone
concentrations will not reach 1980 benchmark levels
until the middle to last half of this century.
At first blush, the strategy to address stratospheric ozone
depletion seems relatively simple: reduce emissions of
ODSs and shrink the ozone hole. However, the data
and the models suggest that the chemical and meteorological relationships between ODSs and stratospheric
ozone levels are anything but simple and that restoration of stratospheric ozone is not occurring along the
timelines originally predicted. Z
Jennifer Sharp Seinfeld
Principal
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