3.
Analysis of Two Issues
Authors
The information in this chapter was prepared by the following contributors.
The first section, describing the Degradation of the Built And Cultural Environment in Arizona, was written by:
o Dorothy Larson, Department of Anthropology, Arizona State University
The second section, describing Ozone Depletion, was written by:
o Suzanne Pfister, Arizona Board of Regents, Phoenix
Degradation of the Built and Cultural Environment
Background
The people of Arizona have been blessed with a vast and rich cultural heritage. Valuable cultural resources, such as the sites and artifacts left by ancient people, historic buildings, and Native American sacred sites, abound in the state.
It has been estimated that Arizona contains one million cultural resources. This projection is based only on the number of properties that have been identified and formally recorded. These resources represent potential knowledge to residents and researchers alike. The numerous archaeological sites contain important non- replaceable information about the lifeways of Arizona's ancient cultures.
These cultural resources have value that extend beyond this purely academic realm. National studies indicate that historic preservation creates pride as well as a sense of community, and thus improves the quality of our lives. This measure of the quality of life has implications for economic development as well. Many corporations take into account the quality of life of an area prior to relocation or expansion.
Cultural heritage tourism provides a more direct measure of the economic impact of historic preservation.
o For example, in 1990, tourists and travelers spent $7.9 billion in the state of Arizona.
o In 1991, there were more than 2.5 million visits to Arizona's national and state historical parks. This figure represents an increase of over 50 percent in the last decade.
o Data collected by the National Trust suggest that 50 percent of Arizona travelers visit an archaeological or historic site.
Thus, the value of Arizona's cultural heritage, in terms of tangible economic benefits, as well as more intangible ones, is obvious. The importance of this cultural heritage is also clearly recognized by the citizens of Arizona. In 1990, Arizona voters approved legislation that provides $1.7 million annually from the state lottery fund to be applied toward the preservation of cultural resources.
Study Resources
The discussion in this section draws primarily on qualitative information collected from numerous preservation experts from across the state. These individuals represent a broad spectrum of perspectives, including state and federal agencies, Native American tribal government, municipal government, and private companies.
The list of individuals consulted was in no way all-encompassing. In order to gain additional, more broad-based data, several publications were also consulted.
Threats to Arizona's Cultural Resources
It is clear is that Arizona's cultural resources are threatened.
Because little systematic information has been collected about the threats to cultural resources, however, it is difficult to understand them, and literally impossible to quantify them. The biggest threats to cultural resources include the following:
o Intentional destruction such as commercial and non-commercial vandalism
o Unintentional alteration or disturbance such as that caused by recreational tourism or insensitive remodeling
o Urban and rural development
o Inadequate maintenance or neglect
o Fire
o Erosion
o Effects caused by other environmental issues such as toxic spills or dumps natural catastrophes.
Vandalism
Nearly all of the professionals who were consulted cited vandalism as the greatest threat to archaeological sites. Vandalism is also a threat to many historic buildings, particularly those in blighted urban areas. Vandalism can be broken-down into two major categories: commercial and non-commercial.
o The major motivation in commercial vandalism is selling artifacts for profit. Types of sites facing the greatest threats from commercial vandalism are Native American burials, and highly-visible archaeological habitation sites. These types of sites are the best sources of ceramic vessels, which are worth a great deal of money on the black market.
o Non-commercial vandalism includes everything from the malicious destructive vandalism that often takes place in abandoned historic buildings, to people chipping out pieces of rock art for their fireplace, or collecting artifacts for their personal collections.
Both types of vandalism have a long history in the state of Arizona and elsewhere in the American Southwest. Data from the Roosevelt Archaeological Project (Rice, personal communication 1994) demonstrates the longevity and seriousness of the problem.
o In the 1920s and 1930s, commercial vandals systematically destroyed 95% of the human burials located within the Roosevelt project area. This vandalism was motivated by the sale of ceramic vessels to local museums.
There are no precise figures on the total number of sites that have been vandalized in Arizona. The following excerpt from Pilles (1988) provides a good illustration of the complexity of the issue, as well as the general nature of vandalism in Arizona:
----------------------------------------------------------------- | ...On the Coconino National Forest, approximately 25 | | percent of all sites have been vandalized (Coconino | | National Forest 1987). Such figures can be misleading, | | however, because not all types of sites are likely to be | | vandalized. The more numerous small or ephemeral sites are | | usually overlooked by the pot hunter in favor of the larger | | pueblo ruins, caves, and cliff dwellings, where "loot" is | | more abundant. Pueblos dating past AD. 1300 are | | particularly susceptible to pot hunting not only because | | of their large size, but also because of the beautiful | | pottery that is typical of this period. One study for | | example, found that 30 percent of all sites on Perry Mesa, | | a rich archaeological region 70 mi. north of Phoenix, had | | been vandalized. Although 7 percent of the small pueblos | | had been pot hunted, 91 percent of the larger pueblos had | | been vandalized (Fish, Moberly, and Pilles 1975: Table 5). | | In addition, virtually every post-AD. 1300 pueblo known in | | northern Arizona has been vandalized, usually quite | | severely. | -----------------------------------------------------------------
Despite increasing law enforcement and public education, vandalism continues to be a threat to Arizona's cultural resources.
o For example, with increased law enforcement and successful prosecution of vandals on public lands, Navajo Preservation officials have noted that commercial vandals are being pushed onto tribal lands, which are very isolated and have fewer law enforcement officials.
Additional data collected by Pilles (1988) from a rock art site in northern Arizona suggest that non-commercial vandalism increases with increased population density or increased visitor traffic. The population of Yavapai County more than doubled from 1970 to 1980. During that time period, graffiti found at several rock art sites increased by 250 percent.
Unintentional Human Disturbance or Alteration
Unintentional human disturbance includes many effects of recreational tourism such as off-road driving on top of less visible archaeological sites, and people climbing on the walls of ruins.
This category also includes effects to historic buildings, such as inappropriate renovation. Many preservation officials cite increasing unintentional, non-malicious human impacts as the greatest threat to the archaeological resources of the Colorado Plateau. With increasing tourism, sites are becoming threatened by the uninformed public, who, in the words of one official, may be "loving our sites to death."
Urban and Rural Development
Threats from development range from large-scale construction to small-scale ranching and agriculture. The main types of development affecting cultural resources include real estate development, road construction, mineral exploration and extraction, transmission line construction, timbering, ranching, recreation, and agriculture.
There are no available data on the exact magnitude of the effects of development on cultural resources. The Arizona State Historic Preservation Office (SHPO) records an average of 1700 development projects a year on federal and state land alone. In the Phoenix area, the devastating effects of development in the state's most urban environment are apparent.
o For example, of approximately 45 Hohokam platform mounds, only three remain.
Data on historic buildings are just as grim.
o For example, of 369 neighborhood grocery stores dating to the year 1935, only 32 are still standing, and their historic integrity is questionable.
Data on more recent development are only slightly more encouraging.
o For example, in 1984, the city of Tempe recorded 159 historic buildings as eligible for listing on the National Register of Historic Places. To date, 29 of these buildings are now gone--a loss of approximately 3 buildings per year.
Data from across the entire state suggest that up to 60% of the historic buildings that have been demolished may have been destroyed due to development.
An intensive review of only a small fraction of SHPO records suggests that development affects more resources in urban areas than in rural.
o For example, approximately 30% of all sites affected by project development in 1994 were located in the Phoenix area or in Tucson.
Preservation Laws
There are, however, federal and state laws that provide some measure of protection for cultural resources. These laws require that the effects of actions to cultural resources on public, Indian, state, and some municipal or county lands, be taken into account.
To comply with legislation, agencies are required to inventory cultural resources on lands that will be affected by actions undertaken in their jurisdiction. If significant cultural resources are found, an assessment of the effects of the action on these resources must be made.
In some cases, if a resource is to be affected by the project, steps are taken to avoid and preserve the property. In other cases, where avoidance is not feasible, steps are taken to "mitigate" the effects of the project on the cultural resource. Generally mitigation consists of recovery of data from the site before it is destroyed. In a small percentage of cases where mitigation of effects from a project is not possible, cultural resources are adversely impacted by development.
Data on file at the SHPO and other agencies suggest that in most cases compliance with preservation law results in the avoidance of cultural resources.
Computer data from 1989 to the present suggests that, on average, 91% of the projects on record did not affect significant cultural properties.
o Less than one percent of projects had an "adverse effect" on significant cultural properties, while an average of eight percent had "no adverse effect" to significant cultural properties. Determinations of "no adverse effect" to archaeological sites generally means that data were collected from the site prior to project impact.
o For historic buildings, "no adverse effect" generally means that alterations to the building are made in compliance with federal standards. "Adverse effects" result when it is not possible to mitigate the effects of project actions.
For example, the disturbance of human remains is considered an adverse effect. In this case, however, agreements are written to ensure that these remains are treated in accordance with Native American concerns.
Avoidance and Preservation on Public Lands
Data from public lands such as land administered by the Bureau of Land Management (BLM) and U.S. Forest Service (USFS) suggest an even more rigorous program of avoidance and preservation of cultural resources (Altshcul and Fairley 1989).
Although preservation professionals often debate how effective this policy of avoidance is in site preservation and management, or conversely, question the desirability of 'mitigation' of the effects of development, it clearly is preferable to no protection at all. Based on the above data, federal, state, and local legislation does provide significant protection for cultural resources.
Protection on Private Land
In contrast, with the exception of human remains and associated materials, most cultural resources located on private land are not afforded any form of protection by law and thus, face the greatest risk from development. In addition, some local governments do not have preservation ordinances in place. However, on a positive note, 73% of Arizona's land is under federal, tribal, or state jurisdiction.
Native American Sacred Sites and Burials
One group of site types, Native American sacred sites and burials, must be considered distinct when reviewing impacts from development.
As mentioned previously, it is not possible to mitigate adverse effects when human remains are disturbed. Most often burial remains are discovered during a project and can not easily be avoided or preserved. Although Native American sacred sites or traditional cultural properties are protected by federal legislation, these types of resources present preservation professionals with unique challenges.
o For example, protection of sacred sites often requires that Native American groups reveal information on the location of areas. This information has generally been kept secret in the past, and many Native Americans are reluctant to reveal these data.
The general consensus of Native Americans and professionals alike, is that existing preservation law does not deal with these issues well.
Neglect
There are no quantitative data available on the adverse effects of neglect on cultural properties.
According to the State Historic Preservation Office, however, neglect is nearly always at the root of all other threats to historic buildings. Neglected buildings are the most likely to be vandalized and to be destroyed by fire. They also suffer the most damage from erosion.
In addition, buildings that have been allowed to deteriorate over time, are at greatest risk from destruction due to development. If a building is not adequately maintained, it may not be economically feasible to restore it for adaptive re-use.
Archaeological sites that have been excavated or stabilized for interpretation, but are not adequately monitored and maintained, also are more likely to be vandalized. They also suffer greater impacts from erosion.
Fire
Destruction of cultural resources by fire is frequently closely related to other types of impacts.
o For example, fire is one form of vandalism that occurs in historic buildings, particularly those in blighted urban areas.
o In addition, unintentional fire caused by unauthorized occupants of these abandoned buildings is also a danger.
Natural fires also frequently destroy rural historic properties and may adversely impact archaeological sites.
o For example, a fire at Mesa Verde National Park in the late 1980s caused damage to some archaeological sites.
Efforts to fight these fires can also negatively impact cultural resources, although many federal land-managing agencies have developed programs to help address this problem.
Data on file at the SHPO suggests that fire is second only to development in the removal of historic buildings. Approximately 35% of all destruction of historic buildings was caused by fire.
Erosion
Estimates of the percentage of archaeological sites that have been impacted by erosion range from 40% to over 90%.
The degree of this impact varies considerably from site to site, depending primarily on a site's physical setting. In general, the effects of erosion are low-grade and continuous rather than intensive. However, the cumulative effects of erosion can be devastating.
o For example, data from the Roosevelt Archaeological Project (Rice, personal communication 1994) suggest that nearly all of the oldest cultural remains, those dating from approximately 12,000 to just over 2,000 years ago, have been destroyed by erosion.
In general, however, the most devastating impacts of erosion are those that are hastened by human action. These impacts include the effects of over-grazing and mining, impacts from dirt roads and off-road driving, effects from water projects that significantly alter the natural environment, and vandalism to name only a few.
Other Environmental Issues
Other classic environmental issues such as accidental spills, the cleanup of hazardous spills or dumps, outdoor air pollution, and natural catastrophes such as flooding all have implications for cultural resources. The level of destruction due to these processes is not well-understood, however, and is restricted to anecdotal information.
Arizona's Cultural Resources At Risk
As is evident from the above discussion, the topic of risks to Arizona's cultural resources is broad and complex. Threats to cultural resources are numerous, and they vary from property to property, depending on a variety of factors. In order to simplify the issue, the most important of these factors are identified and described below.
Type of Cultural Resource
Types of cultural resources include cliff dwellings, rock art sites, and historic buildings. Such highly visible archaeological sites, such as large prehistoric habitation sites or rock art sites, are more likely to be impacted by intentional vandalism than other kinds of cultural resources.
Cultural Setting
The cultural setting focuses on the location of a resource in terms of such things as urban vs. rural. It has been demonstrated in several areas of the state that increased population density or increased visitation generally results in increased vandalism as well as unintentional damage to cultural resources.
Physical Setting
The physical setting focuses on the location of a resource in terms of such things as floodplain and rockshelter. The physical setting of a resource is a primary determinant of how much erosional impact it will face. The physical setting also plays a factor in how accessible and visible a site is to the general public.
Property Ownership
Property ownership focuses on ownership of a resource in terms of such entities as federal, Indian, state, city, county, and private owners. The jurisdiction of a property in question determines how much protection it is afforded by law. In addition, government agencies have different mission statements. Differences in the land managing agencies' overall missions create different kinds of pressures on cultural resources.
Conclusions
Because little quantitative data are available, and because there is no consensus among all preservation professionals, it is not possible to absolutely define the threats to cultural resources. One area of agreement among preservationists, however, is that Arizona's cultural heritage is in danger of being lost.
Table 3.1 on the following page provides a summary of the general relationships between the factors and the risks described in this subsection.
Table 3.1 Threats to Cultural Resources by Resource Type
-------------------------------------------------------------------------------------------- | Threats to Cultural | Types of Resources Most at | Risk Areas | | Resources | Risk | | ============================================================================================ | Commercial vandalism | Native American burials | Isolated areas | | | | | | | Highly visible archaeological | Private land | | | sites | | -------------------------------------------------------------------------------------------- | Non-commercial | Rock art | Densely populated or | | vandalism | | high traffic areas | | | Other highly visible | | | | archaeological sites | | | | | | | | Historic buildings | | -------------------------------------------------------------------------------------------- | Recreational tourism/ | Ephemeral archaeological sites | Densely populated or | | Unintentional destruction | | high traffic areas | -------------------------------------------------------------------------------------------- | Inappropriate alteration | Historic buildings | All areas | -------------------------------------------------------------------------------------------- | Development | All types of cultural resources | Urban settings | | | | | | | | Private land | -------------------------------------------------------------------------------------------- | Neglect | Historic buildings | All areas | -------------------------------------------------------------------------------------------- | Fire | Historic buildings | All areas | -------------------------------------------------------------------------------------------- | Erosion | All types of cultural resources, | Over-grazed areas | | | but especially those that have | | | | been previously altered by | | | | human activity | | --------------------------------------------------------------------------------------------
Acknowledgments
I would like to gratefully acknowledge the help of the following individuals:
Gary Stumpf, State Office of the Bureau of Land Management; Leigh Jenkins, Hopi Tribe; Alexa Roberts, Navajo Nation Historic Preservation Office; Ken Rozen, State Lands Department; Bob Gasser, Dr. Jim Garrison, Mary Estes, Bill Collins, Cheri Palomino, Arizona State Historic Preservation Office; Debbie Abele, Todd Bostwick, City of Phoenix; Dr. J. Simon Bruder and Dr. A.E. Rogge, Dames & Moore; Dr. Glen Rice, Office of Contract Management, Arizona State University; Dr. Charles Redman, Department of Anthropology, Arizona State University.
Background
Ozone is a reactive form of oxygen made up of three oxygen atoms, instead of the two oxygen atoms found in the normal oxygen we breathe.
Ozone molecules absorb certain wavelengths of biologically damaging ultraviolet light. It is the only gas in the atmosphere that does so, and therefore, is an essential part of the Earth's ecological balance. The evolution of land life is believed to be tied closely to the formation of the protective ozone layer (Kowalok 1993:16).
The popular media refers to ozone in two ways:
o Stratospheric ozone
o Atmospheric or "ground level" ozone
Stratospheric Ozone
Most of the ozone in the atmosphere is concentrated in the thin air of the stratosphere, between 6 and 30 miles up, where it filters out ultraviolet light from the sun before it reaches the surface. This ozone is known as stratospheric ozone.
The thickness of the stratospheric ozone layer varies during the seasons of the year. The layer around the earth is naturally the thinnest near the tropics, although man- made ozone depletion has created thinning of the layer at the polar regions, particularly in Antarctica.
Stratospheric ozone is constantly being created and destroyed by ultraviolet light in a kind of balance. The amount of ozone in the stratosphere naturally fluctuates a great deal on a daily and a seasonal basis. Long-term measurements of stratospheric ozone concentrations show a definite and alarming trend, after the natural variations are taken into account. The most dramatic example is the worsening "ozone hole" that forms in September and October each year over Antarctica.
Atmospheric or "Ground Level" Ozone
Atmospheric ozone is found in the troposphere, which is measured from ground level to about six miles up. It is a component of smog and is a harmful air pollutant to humans. Although chemically the same, the concentrations of stratospheric and atmospheric ozone vary greatly, as do their impacts to life on earth.
The Importance of Ozone
Ozone in the stratosphere is important because it filters out harmful ultraviolet radiation.
With each percentage drop in stratospheric ozone levels, scientists estimate the strength of ultraviolet radiation increases by 1.25% (Science News 1993:260).
The most notable effect of increased ultraviolet radiation is the increase of skin cancer.
o The United National Environment Program predicts a 26% rise in the incidence of non-melanoma skin cancers world-wide if overall ozone levels drop 10 percent (Lemonick 1992:61.3)
o The USEPA has estimated that there will be an increase of 20,000 skin cancer cases for every one percent decrease in ozone levels.
In addition to the increase in skin cancer, additional ultraviolet radiation can also result in the following:
o Impair immunity to infectious diseases
o Reduce the yield of crops such as soybeans
o Disrupt the delicate biologic processes in plants and animals
o Kill phytoplankton and krill in oceans, which will, in turn, disrupt the ocean food chain
o Lead to increases in the number of cataracts in human eyes.
Causes of Ozone Depletion
Both natural and man-made causes of ozone depletion exist, and both result primarily from the reaction of chlorine molecules with the oxygen molecules that make up ozone.
Natural Causes
Natural events such as volcanic eruptions can release volcanic sulfuric acid which contains chlorine. Scientists believe that the 1991 eruption of Mt. Pinatubo in the Philippines was partially responsible for a significant drop in ozone in 1992 (Science News 1993:260).
Unusually cold temperatures at high altitudes can also enhance ozone depletion.
Man-Made Causes
Most indications are, however, that stratospheric ozone declines match the increase in chlorine and bromine emissions from human sources.
Man-made chemicals, primarily in the form of chlorofluorocarbons (CFCs), are the major source of this ozone depletion.
CFCs are used as cooling agents in refrigerators and air conditioners, as blowing agents for foam insulation, and as cleaning agents for electronics manufacturing (Krupp 1995).
Chlorine from CFCs is highly reactive and breaks apart the ozone molecules. Each atom of chlorine can destroy up to 100,000 molecules of ozone, a much faster rate than that at which the gas is naturally replenished (Lemonick 1992:62).
One major difference between chlorine from natural sources and the chlorine in CFCs is that natural chlorine is soluble and often gets rained out in the lower atmosphere. CFC chlorine is inert and insoluble, and therefore tends to make its way up to the stratosphere where it can cause damage. It also remains in the atmosphere long after it is emitted. Some estimates are that the CFCs will last up to 100 years (Science 1993:1580).
It is estimated that more than 20 million tons of CFCs have been emitted into the atmosphere, and researchers believe that, even if the productions of CFCs were stopped tomorrow, levels of chlorine would continue to rise for another 10 to 15 years and natural levels would not be reached for nearly a century.
There are a variety of ozone depleting chemicals in addition to CFCs.
o For example, other precision cleaning solvents, such as methyl chloroform (known as TCA) can cause the same problems as CFCs.
o Certain reactive nitrogen compounds can also destroy ozone.
o Bromine is similar to chlorine
o Halons, which are often used as fire suppressants, are even more destructive than CFCs. For this reason, halon production was phased out world-wide at the end of 1994 (Lemonick 1992:63).
Chlorine, bromine and reactive nitrogen oxides can also come from natural sources, such as volcanoes, biomass burning, and certain ocean processes. This fact raised questions about nature's role versus man's impact during the early days of ozone layer research.
Scientific Research
The issue of ozone depletion first began to surface from research conducted in the early 1970s.
o First, concern was raised over nitrogen emissions in the exhaust of the proposed supersonic transport airplanes (SSTs).
o Research was also done as part of an analysis of the potential impacts of the National Aeronautic and Space Administration's (NASA) injecting chlorine into the stratosphere from the space shuttle solid rocket boosters.
By 1974 the focus of scientific research had shifted to the chlorine released by CFCs. In September 1974, the CFC threat caught the attention of the American media, and subsequently a ban on aerosol cans was instituted by the federal government (Kowalok 1993:19). Other federal and international controls followed.
The most telling indication that ozone depletion was occurring came in 1986, when an ozone "hole" was confirmed over Antarctica. It was known that concentrations of CFCs collect in the polar regions and that the colder climates enhance the breakdown of ozone molecules when they finally come into contact with the sun. Antarctica also had stronger wind patterns than other areas of the world and kept the chlorine particles in the stratosphere for longer periods of time.
The ozone layer has been getting thinner in other areas, as well. Data indicates that there was an average net decrease of about 3 to 4 percent per decade between 1978 and 1991 in the middle latitudes of the earth, an average which excludes the polar regions. The depletion was somewhat worse in the Southern hemisphere and was more apparent in the winter months than in the summer (Parson 1995).
Since 1991, the declines have accelerated even further.
o In 1992 and early 1993 there was a 4 percent average decline and a 2 to 3 percent decline below the lowest value recorded. NASA had also reported up to 3 percent decreases in ozone over North America and Europe (Krupp 1995)
o By 1992, other research showed ozone losses of up to 20 percent in the Northern Hemisphere (Rowlands 1993:25).
o In 1993, scientists recorded the largest amount of thinning of the ozone layer in Antarctica ever. They determined there was 15 percent less ozone than in 1992, leaving the ozone shield at one-third its normal thickness in this area. This drastic change was felt to be a combination of CFCs, cold temperatures, and the continued impact of Mt. Pinatubo debris (Science 1993).
Regulation of Ozone-Depleting Substances
Scientific discoveries in the early 1980s led to action on an international level to address the ozone depletion problem.
o In 1987, the Montreal Protocol, signed by 27 countries, specified that CFC emission should be reduced by 50 percent by the year 2000.
o In 1990, 87 countries signed an expanded agreement, which moved up the timetable and called for a total phase-out of CFCs by the year 2000.
o In 1992, the phase-out was accelerated again as countries agreed to a 75 percent reduction in CFCs by January 1994 and a total CFC elimination by January 1996. The agreement also established a "grace period" for developing countries to 2006 (Rowlands 1993:30).
At first it was thought that CFCs could never be replaced, but industries around the world have met the technological challenge and allowed a tightening of the phase-out schedule, and the impact of the accords has been significant.
o EPA estimated that the original 1987 Protocol would prevent 1.2 million cataract cases around the world, 137 million cases of skin cancer, and 27 million skin cancer deaths (Brown 1992:160).
o Since the Montreal Protocol was signed there has been a 50 percent drop in CFC consumption, largely due to industries phasing it out of their processes.
o In 1992 alone, there was a 12 percent decline in CFC production (Brown 1993b:66).
o Several major companies world-wide will eliminate the use of CFCs by 1995, fully five years ahead of the required deadline.
With these trends it is expected that the concentrations of CFC chlorine will peak around the year 2000, and then decline. The ozone hole in Antarctica is expected to fully recover by the year 2066.
Perceptions of Risk
Certain individuals and groups have been outspokenly critical of the generally accepted, and continually evolving, understanding of stratospheric ozone depletion and the role of man-made chemicals.
There are still a number of scientists around the world who do not believe in the ozone depletion theories. They maintain that most of the chlorine in the stratosphere is coming from such things as sea salts, volcanoes and burning biomass, not from CFCs.
National figures such as Rush Limbaugh and former Washington Governor Dixie Lee Ray have said that the depletion is a hoax, and even articles in the Washington Post and Omni magazine have questioned whether any damage has been done by this phenomenon.
Critics contend that there are not enough scientific data, and that this is a politically motivated issue driven by "media-friendly pressure groups, wielding a power over public perception that is totally out of proportion to any scientific competence they possess" (Hogan 1993:37). These critics often rely on out-dated research papers from earlier scientific periods before additional research provided more definitive evidence.
No matter what their perspective, most scientists agree that more research is necessary. Ozone depletion was not a subject of scientific research until recently, and there are a great many variables, such as weather patterns, natural events and local climatic conditions that can affect the distribution of ozone around the earth.
Throughout the spring of 1994, NASA conducted high-altitude flights with scientists aboard to measure concentrations of CFCs, hydrochloroflurocarbons (HCFC), and other ozone-depleting chemicals. It is particularly important to check the occurrence of the HCFCs, since they have no chlorine and have replaced most CFCs in the marketplace.
Criteria Evaluation of Ozone Depletion
Ozone depletion appears to pose unknown and probably moderate risks to Arizona unless some major change occurs within the next few years.
o For example, more severe problems could occur if the stratospheric chlorine levels cross a threshold and create drastic damage to the ozone layer.
The potential for serious impacts remains largely on the global scale, and solutions need to be properly managed in order to avoid significant human impacts. The following subsections describe some of these potential impacts by various criteria.
Economics
The present value damages are almost impossible to calculate for Arizona, but the actual rate of ozone thinning in the region has not been clearly defined. If the ozone layer continues to decrease in our stratosphere, the following economic losses could be sustained:
o Agriculture
o Diminished availability of surface water
o Increases in health care costs related to the treatment of skin cancers and cataracts
o Greater energy consumption to handle increased cooling needs
Positive economic benefits from local efforts to reduce ozone depletion are also possible. Good planning for the phaseout of commercial air-conditioning systems can result in savings from greater energy efficiency and from recycling of expensive refrigerants. These savings can offset the cost of replacing old equipment.
Therefore, the present value damages are probably less than $1 million in Arizona; hence, this could be considered a less severe impact.
Fairness
Since ozone depletion is a global issue affecting the stratosphere above Arizona, it will tend to affect all residents equally. Scientists have determined that the middle latitudes of the earth have seen a small (3% to 4%) decline in the ozone layer but that the detection has been primarily in the northern part of the United States.
A potential problem could exist for low-income and elderly people who own older cars and cannot "top off" their air-conditioning refrigerant each spring. If maintenance or repair becomes too expensive, they may have to do without air conditioning in the hot summer months.
Future Generations
Since CFCs have a life expectancy of roughly 100 years, ozone depletion will clearly affect future generations.
According to the available scientific data, the concentrations of CFC chlorine are expected to peak in the year 2000 and then decline. Full restoration of the ozone layer is not expected until at least 2066. Thus, ozone depletion will have a long-term impact, but since there is a very good chance for amelioration, it is considered to have a moderately severe impact.
Aesthetics
A diminished ozone layer will likely cause changes in vegetation. Resistance to ultraviolet radiation varies dramatically across species, so some changes would undoubtedly occur.
A diminished ozone layer could also adversely affect local ecosystems, leading to reductions in vegetation, water supplies and biological life.
Personal comfort could also be affected, both from the temperatures and from the quality-of-life impacts caused by potential solutions. Given present conditions, however, this would be considered a low impact.
Peace of Mind
This environmental problem has had international media attention for over a decade, and although there are still some mixed feelings about the severity of the issue, concern among the international community has been strong enough to warrant stringent industry restrictions and prohibitions in manufacturing CFCs.
Because it is an involuntary risk, citizen concern may be somewhat greater, but the sense of adverse impact is not as strong in Arizona as it is in countries such as Australia, which has developed extensive media campaigns to encourage people to stay out of the sun because of the thinning ozone layer in the Southern hemisphere.
There is some concern, however, because of the existing sensitivity of Arizonans to excess sun. Since Arizona already has the highest skin cancer rate in the country, any indication that more ultraviolet radiation might be falling on this locale would negatively impact our peace of mind. This could be considered a low to moderate impact.
Social Impacts
The social impacts from ozone depletion will be low, because these impacts tend to affect all populations. A diminished ozone layer could create greater negative impacts for people who must spend more time working and/or living in the outdoors. They could be more susceptible to skin cancer, and their immune systems could be weakened by exposure to additional ultraviolet radiation.
Recreation
Increased temperatures could impact recreation areas around the state by reducing available water supplies, limiting aquatic life, and destroying vegetation. Greater ultraviolet radiation could also limit the amount of time people can spend enjoying the outdoors without fear of adverse health impacts.
Overall Impact
The overall impact of ozone depletion is still fairly low.
Although the rate of ozone depletion will continue to rise modestly in the next decade, the immediate impacts to Arizona have not been well documented.
With every percentage decrease in the ozone layer, scientists expect an increase of 20,000 skin cancer cases in the United States.
Given the extensive international efforts to halt CFC production and the efforts by US. manufacturers to accelerate the transition to chlorine-free alternatives, there may be increased ultraviolet radiation in the stratosphere over Arizona, but that it should not rise to such a significant level as to pose a moderate or severe environmental risk.