Science, and transportation united states senate

mix with the ozone and destroy it in a catalytic manner. In other

words, during the process in which the NO x would destroy the ozone,

the XO x would be reformed and released to destroy still more ozone

in a continuous manner. 53 The mechanisms for this process appeared

reasonable and worthy of serious study. However, Dr. John J.

McKetta of the CEQ noted that the total NO x burden produced by

combustion processes amounts to only about 2 percent of that produced

by dying vegetation in the natural cycle of plant life. 54 It was then

noted that the artificial insertion of nitrogen compounds into the soil

for purposes of fertilizing caused the evolution and ultimate release

of XO x in quantities amounting to a sizable fraction of that produced

by nature. 55 • 56

Moreover the bromine compounds used in agriculture as antifungi-

cides were held to be even more potent in destroying ozone than NO x . 57

Still more very large sources of NO x were identified, such as lightning

from the some 5.000 storms around the Earth, each day. Also, air

bursts of nuclear bombs produce NO x at the rate of 10,000 tons per

megaton of yield. 58, 59 In the early 1960 ? s, 340 megatons of explosive

injected about 3% million tons of XO x into the stratosphere.

52 "Climatic Impact Assessment Program Development and Accomplishments, 1971-75,"

J. Mormino, et al., D0T-TST-76-41, December 1975.

53 "Reduction of Stratospheric Ozone by Nitrogen Oxide Catalysts from Supersonic Trans-

port Exhaust," H. Johnston, Science, Aug. 6, 1971.

54 "The Eight Surprises," J. J. McKetta. address to the American Trucking Association,

Oct. 16. 1974. reprinted in the Congressional Record. Mar. 12, 1975.

55 "NOAA Scientist Weighs Possible Fertilizer Effects on Ozone," Paul Crutzen, Depart*

ment of Commerce News, Apr. 15, 1975.

56 "Nitrogen Fertilizer Threatens Ozone," quotes from J. McElroy, Washington Star,

Dec. 12. 1974.

57 "Weather Warfare" (Bromine). New Scientist, Mar. 27, 1975, p. 762.

58 "Ozone Appears Unalterpd by Nitric Oxide," Kenneth J. Stein, Aviation Week and Space

Technology, Nov. 6, 1972. p. 28. • • . ^ , r ,

. 59 "Nitrogen Oxides, Nuclear Weapon Testing, Concorde and Stratospheric Ozone," P.

Goldsmith, et at, Nature, Aug. 31, 1973, p. 545.

34-857—79 14

174

It had begun to appear to many that, in the Earth's atmosphere,

ubiquitous and that there was just no legislative way to save the ozone

from the catalytic disintegration hypothesized. The issue endures

largely as an academic debate, though its character could change again.

One group holds that the destructive mechanisms ascribed to NO x are

real and that ozone density is controlled by the presence of NO x - An

opposing group contends that, while the hypothetical reactions appear

to be sound, they just don't seem to occur. The insertion of 3% million

tons of XO x by nuclear explosions over 1 year's time, for example, was

judged by many as an experiment of sufficient magnitude to cause un-

mistakable perturbations in ozone density, and would prove or dis-

prove the destruction hypothesis. Recordings of ozone density before,

during, and following the test were analyzed by numerous people. One

investigator detected trends which he associated with the explosions ;

however, others held that "the conclusion that massive injections of

nitrogen oxides into the stratosphere do not upset the ozone layer seems

inescapable." 60

Putting that aside, yet another challenge to the ozone, the manmade

fluorocarbons (freon aerosol propellants and refrigerants) has been

postulated. 61 The hypothetical mechanisms by which these compounds

would migrate into the stratosphere, break down to release odd chlorine

molecules which would in turn set up a catalytic destruction of ozone,

where examined and found to be plausible and a cause for concern. Sub-

sequent measurements taken in the stratosphere proved the presence of

numerous odd chlorine molecules, some of which could indeed be shown

to have their origin in freon. 62

Although the empirical validity of the destructive interaction of

these odd chlorines with ozone is difficult to show and has yet to be

shown, their discovery in the stratosphere was enough for several

scientists to call for a ban on the fluorocarbons. Other scientists, as well

as industry, took an opposing view, calling for empirical proof prior to

taking actions to ban or control the manufacture or use of freon

propellants.

The argument became partly one of timing with one side claiming

that no emergency could be proven and plenty of time was available to

test the destruction hypothesis. Opposing this was the view that it may

very well be too late already since most of the freons already released

have yet to reach the stratosphere.

Unlike the case with XO x . where changes as vast as banning the

use of nitrating fertilizers might be required, the control of freon

release was a manageable target for a regulatory control. The resulting

studies and actions represent a model of rapid and cooperative action

between a large number of highly diverse Government offices and

agencies. The decision was made to act without waiting for empiricial

proof of the destruction hypothesis, but not to institute the total and

immediate ban some investigators called for. Instead, propellant ap-

plication would be labeled as possibly hazardous to the ozone and then

"° I '»id.

r; "Stratospheric O^one Destruction hv Man-made Ohlorofluoromethanes," R. J. Cicerone,

et al.. Science, Sept. 27, 1974.

""Atmospheric Halocarbons and Stratospheric Ozone," J. E. Lovelock, Nature, Nov. 22,

1074.

i banned in stages. Refrigerants would be studied pending their possible

regulation at some future time.

Action by the Government on the regulation of fluorocarbons

The Council on Environmental Quality (CEQ) and the Federal

Council for Science and Technology (FCST) reviewed theoretical

oapers on the destructive interaction between fluorocarbons and ozone,

the first of which appeared in 1974. They decided that the case was

worthy of serious concern. In January 1975, the CEQ and FCST

jointly created a large ad hoc task force known as the Federal Inter-

agency Task Force on Inadvertent Modification of the Stratosphere

(IMOS). IMOS membership included representatives from:

Interdepartmental Committee for Atmospheric Sciences (ICAS).

Department of Agriculture.

Department of Commerce,

Department of Defense.

National Institute of Environmental Health Sciences.

Food and Drug Administration.

Department of Justice.

Department of State.

Department of Transportation.

Energy Research and Development Administration.

Environmental Protection Agency.

Consumer Products Safety Commission.

National Aeronautics and Space Administration.

National Science Foundation.

Council on Environmental Quality.

Office of Management and Budget (observer only) .

The work of IMOS was swift and orderly. A series of studies was

completed and published in their report by June 1975. 63 IMOS con-

cluded "that fluorocarbons released to the environment are a legitimate

cause for concern." The report also referred to a similar study which

was then underway at the National Academy of Sciences. IMOS rec-

ommended that, should the results of the NAS study agree with their

results, then Federal regulatory agencies should initiate rulemaking

procedures for implementing regulations to restrict fluorocarbon uses.

The data base for the NAS study was of course the same data base

used by IMOS since it was the only one available. The conclusions

reached by both studies were therefore the same, and rulemaking was

instituted.

If the data base could have contained some empirical proof sup-

porting the validity of the massive ozone destruction hypothesis, the

rulemaking procedures would have proceeded without, or at least with

much less debate and protest. As it was, the rules were handed down

without proof, the justification being that the consequences of higher

UV exposure due to ozone thinning were sufficiently severe that pre-

cautionary regulations were necessary. Under these circumstances, the

rules Ave re models of compromise. A ban was to be issued over the pro-

test of industry, but it would neither be the complete ban nor the imme-

diate one demanded by the environmental groups and some scientists.

63 '"Fluorocarbons and the Environment," IMOS. Council on Environmental Quality and

the Federal Council for Science and Technology, June 1975.

176

The proposed rules were formulated jointly by the Department of

Agency, and the Consumer Product Safety Commission. In brief, they

state :

1. By October 15, 1978, no company may manufacture fluoro-

carbons for use in aerosol products.

2. By December 15, 1978, companies must stop using fluorocar-

bons as propellants in aerosol products.

3. As of April 15, 1979, no spray product containing a fluoro-

carbon propellant may be introduced into interstate commerce.

Products on store shelves at that time may be sold, however, and

there will be no recall.

4. Beginning in October 1978, warning labels will be put on

aerosol products which contain fluorocarbons to warn the user

that the fluorocarbons are present and may affect the ozone.

5. Certain aerosol products intended for medical purposes are

exempt from these regulations.

The rule on labeling has already been put into effect. 64

Climatic effects of ozone depletion

While the effect of a significant buildup in the concentration of

chlorofluorocarbons and chlorocarbons on the chemical balance of the

Earth/atmosphere system is currently a subject of concern, their im-

pact and effect on the Earth's overall thermal energy balance must

also be considered. The chlorofluorocarbons and chlorocarbons have

strong infrared absorption bands, thus allowing these compounds to

trap long-wave radiation emitted by the Earth and, in turn, enhance

the atmospheric "greenhouse effect." This enhancement may lead to

an appreciable increase in global surface and atmospheric temperature

if atmospheric concentrations of these compounds reach values of the

order of 2 parts per billion (ppb) , 65

Furthermore, ozone itself is important to the Earth's climate because

it absorbs some quantities of both solar and terrestrial infrared radia-

tion, thereby affecting the enerofv balance of the Earth/atmosphere

system that determines the Earth's temperature. Exactly how changes

in the ozone concentration might affect climate are far more difficult

to determine, since changes in surface temperature from variations in

ozone depend on such diverse factors as whether the total amount of

ozone is increased or decreased, whether the height at which the maxi-

mum amount of ozone occurs is altered, or whether the latitudinal

distribution of ozone is disturbed. James Coakley of the National Cen-

ter for Atmospheric Research (NCAR), Boulder, Colo., has found

that a uniform reduction in the total amount of atmospheric ozone

would lead to a cooling of the Earth's surface, but that a decrease in

altitude in the stratosphere where ozone has its maximum concentra-

tion can warm the surface. Similarly, an increase in total amount of

ozouo warms, but an increase in the altitude of maximum ozone con-

centration can cool the climate. If it were known that an atmospheric

« The previous section on the ozone depletion Issue was contributed by George Chatham,

Spprinllst In Aeronautics and Space, Science Policy Research Division, Congressional Re-

peareh Service.

* Rnmanathan. V., "Greenhousp Effect Due to Chlorofluorocarbons: Climatic Implica-

tions" Science, vol. 190, Oct. 3, 1975, pp. 50, 51.

177

ozone in the atmosphere, then before one could conclude that this would

lead to a global cooling, it would still also have to be known if the

clilorofluorocarbons moved the altitude of maximum ozone concen-

tration up or down. If the maximum moved up, this would enhance

the cooling effect of a decrease in ozone, but if the maximum moved

down, that situation would oppose the cooling attributable to the

decrease in total ozone. Thus, while it is conceivable that a large change

in ozone could significantly affect climate, it may be seen that the

direction of any potential ozone-climatic effect is difficult to deter-

mine. 66

WASTE HEAT

Another man-generated pollutant that could affect the climate is

waste heat generated by combustion, automobiles, home heating, in-

dustrial processes, and power generation — all produce heat that even-

tually is emitted into the atmosphere. In addition to its direct effect

on atmospheric temperature, in specific situations waste heat can en-

hance convection, the vertical motion so important in precipitation

processes.

On a regional scale, thermal effects may become important by the

turn of the century. However, on a global scale, climatic effects of

thermal pollution today and for the near future appear to be insig-

nificant. Some scientists, however, believe this impact may grow with

increased energy production and conversion. Research meteorologist

James T. Peterson of the Environmental Protection Agency states

that a long-term view reveals that continued growth of energy use

could lead to a large-scale climatic change in 100 years or more. Of

particular concern, says Peterson, are present-day nuclear power-

plants, which will produce about 55 percent more waste heat than a

fossil fuel plant for a given amount of electricity generated. 67

To better understand the effects of heat releases on weather and

climate, the U.S. Department of Energy is sponsoring a program called

METER, which stands for "meteorological effects of thermal energy

releases." METER program scientists are collecting data from several

powerplant sites around the United States to aid in predicting the

specific environmental effects of releasing large amounts of excess heat

and moisture directly into the atmosphere from powerplant operations

and cooling towers. The amounts of heat and moisture emitted from

the stacks and towers of a large powerplant are small compared with

those released by even a moderate-sized thunderstorm. Cooling tower

plumes are suspected of acting as a triggering mechanism to create

instabilities in the atmosphere, initiating or otherwise modifying

rainfall and disrupting storm patterns. A typical cooling tower will

produce 5,000 megawatts of heat and evaporate 40,000 to 60,000

gallons of water per minute. Even so, a modest thunderstorm will put

out 800 times that much water and 30 times that much heat. 68

The urban "heat island"

• On a local scale, the climatic effects of energy use and heat produc-

tion are significant and well documented. Obviously, urban areas are

66 Schneider. Stephen H., "The Genesis Strategy: Climate and Global Survival." New

York. Plenum Press, 1976. p. 183.

67 Peterson, James T., "Energy and the Weather," Environment, vol. 15, October 1973,

PP. 4, 5, 8.

88 "Power Plant May Alter Weather," the Christian Science Monitor, Mar. 13, 1978, p. 19.

178

experiencing thermal effects. The most evident feature of city climate

island. Cities are prodigious sources of heat. Factory smokestacks, air-

conditioners and heating systems of offices and homes, vehicle engines

and exhausts — all contribute waste heat to the outside atmosphere',

particularly in winter. Summer temperatures in the city are 0.6° C to

1.1° C higher than in nearby rural areas, and 1.1° C to 2.2° C higher in

winter. Also, the building materials of brick, asphalt, mortar, and

concrete readily absorb and store more heat from the Sun than the soil

and vegetation of a rural area, and give it up more slowly after sun-

down. While rural areas are rapidly cooling after sunset, the building

materials gradually release their stored heat to the urban atmosphere,

tending to keep it warmer than the countryside.

Another factor that retains high temperatures and makes the atmos-

phere dry is the way a city disposes of its rainwater or snow. During

any shower or storm, the water is quickly drained from the roofs by

gutters and drainpipes, and from the sidewalks and streets by gutters

and storm sewers. The winter snows are removed as quickly as possible

by shovels and plows, and often hauled away in trucks. These methods

of removing precipitation not only take away sources of moisture but

also remove the cooling effect of evaporation. In the country, evapora-

tion can cool the area where the rain and melting snow stay on the

surface or seep into the ground. A large fraction of the absorbed heat

energy is used in evapotranspiration as vegetation transpires water

vapor.

likelihood of surface-based air temperature inversions (air tempera-

ture increases rather than decreases with height) and increase the

height of the mixed layer near the surface. Inversions inhibit turbu-

lent air motions which diffuse and dilute pollutants. Heat emissions at

the city surface create a relative decrease in temperature with height

which in turn aids the mixing and dispersion of pollutants. Observa-

tions of urban and rural temperature-height profiles have shown this

effect of thermal emissions. Thus, urban pollutants emitted near

ground level, such as carbon monoxide from auto exhaust, will be

diffused through a greater volume of the atmosphere with a consequent

reduction in concentration.

Other major features of urban climates that are related to thermal

pollution include :

A longer frost-free growing season.

Less snowfall because snow melts while falling through the

warmer urban atmosphere and less snow accumulation because

-now melts on contact with warmer urban surfaces.

Lower relative humidity.

Decreased occurrence and density of fog because of the lower

relative humidity, a feature which may be offset by more par-

t Iculate matter which serves as condensation nuclei.

A slight component of the wind direction toward the city cen-

ter as a result of the horizontal temperature contrast.

Apparent enhancement of precipitation downwind of cities, a

phenomenon partially due to increased convection (vertical

motion).

179

The calbedo is a numerical indication of the percentage of incoming

i>lar radiation that is reflected by the land, ocean, and atmosphere back

into space and, attendantly, how much is absorbed by the climatic sys-

tem. Another important manner for altering the Earth's heat budget,

albedo can be changed by the process of urbanization, agricultural

activities, changes in the character of the land surface, and by in-

creasing or decreasing cloudiness. 69

Most clouds are both excellent absorbers of infrared radiation and

rellectors of solar radiation. Therefore, clouds are a major factor in

determining the Earth's energy balance. An increase in clouds could

warm surface temperatures by tending to reduce the flux of long- wave

(that is, infrared) radiation to space, or cool surface temperatures by

reflecting incoming solar radiation back to space. The net effect of

increased cloudiness is to either warm or cool the surface, depending

on cloud type, latitude, and season. 70 The effect of cloud condensation

nuclei (CCN) on the formation of fog and clouds could alter the albedo

of a region if the fog or clouds were sufficiently persistent or extensive,

P. V. Hobbs and H. Harrison, both professors of atmospheric science

at the University of Washington, and E. Eobinson of Washington

State Universit3 T? s Air Pollution Research Unit, contend that perhaps

the most sensitive atmospheric processes which can be affected by air

pollutants are those involved in the development of clouds and pre-

cipitation.

Apart from effects on precipitation processes, inadvertent modifi-

cation of the microstrncture and distribution of clouds, with attend-

ant consequences for radiative properties, could have profound effects

on atmospheric temperature distributions and global climate. 71

Whether a variation in terrain on temperature or other factors would

have a negative or positive feedback interaction with clouds is a

major question in climate theory that will be answered by extensive

analyses of observations and model studies.

The high reflectivity of snow and ice, as compared with water or

land surfaces, provides positive feedback if the average year-round

temperature decreases and the extent of ice and snow coverage in-

creases and reflects more of the incoming sunlight back to space. The

result is to lower the rate of heating still more, particularly in the

regions closest to the poles. Columbia University scientists observed

from a study of satellite photomaps that snow and icepack cover

were more extensive and of longer duration in the early 1970's than

in previous years. The result, they reported, was to increase the

Earth's albedo, reflect more sunlight back into space, and change the

planet's heat balance. 72 It was pointed out that normally vegetated

ground reflects about 15 percent to 20 percent of sunlight and a calm

ocean reflects 5 percent to 10 percent, while snow-covered grassland

or pack ice reflects about 80 percent.

88 Otterman. J., "Anthropogenic Impact on the Albedo of the Earth," Climatic Change,

vol. 1, Xo. 2, 1977, pp. 137-155.

70 "Living With Climatic Change," proceedings of a conference/workshop held in Toronto,