International Environmental Policy:International Environmental Policy:Controlling Ozone Depletion Controlling Ozone Depletion

Ozone: The BasicsOzone: The Basics

Ozone is a naturally occurring gas in the Ozone is a naturally occurring gas in the atmosphere.atmosphere.

An ozone molecule contains three oxygen atoms: An ozone molecule contains three oxygen atoms: OO3.3.

Ozone is found in two layers:Ozone is found in two layers:– ““Bad” ozone: 10% of ozone is in the lower atmosphere Bad” ozone: 10% of ozone is in the lower atmosphere

(troposphere), where it is a toxic component in smog.(troposphere), where it is a toxic component in smog.– ““Good” ozone: 90% is found in the “ozone layer” in the Good” ozone: 90% is found in the “ozone layer” in the

stratosphere (6 to 10 miles above the earth), where it stratosphere (6 to 10 miles above the earth), where it blocks harmful UV-B radiation.blocks harmful UV-B radiation.

Ozone: The BasicsOzone: The Basics

Benefits of “Good” OzoneBenefits of “Good” Ozone

If the ozone layer did not absorb ultraviolet If the ozone layer did not absorb ultraviolet (UV)-B radiation from the sun, people would (UV)-B radiation from the sun, people would suffer more:suffer more:– Skin cancerSkin cancer– CataractsCataracts– Suppressed immune systemsSuppressed immune systems

Ozone DepletionOzone Depletion

Stratospheric ozone is depleted by reactions Stratospheric ozone is depleted by reactions with chemicals produced as gases at ground with chemicals produced as gases at ground level.level.

Important ozone-depleting gases:Important ozone-depleting gases:– Chlorofluorocarbons (CFCs) and other chlorine-Chlorofluorocarbons (CFCs) and other chlorine-

containing gases, formerly used in refrigeration, containing gases, formerly used in refrigeration, air conditioning, and other uses.air conditioning, and other uses.

– Bromine-containing gases (mostly “halons”), Bromine-containing gases (mostly “halons”), originally developed to extinguish fires.originally developed to extinguish fires.

Ozone DepletionOzone Depletion

Stratospheric ozone Stratospheric ozone concentrations have concentrations have dropped by about dropped by about 3%, on average, 3%, on average, since the 1980s.since the 1980s.

Ozone Ozone concentrations have concentrations have fallen more near the fallen more near the poles, and not at all poles, and not at all near the equator.near the equator.

Ozone DepletionOzone Depletion

Estimated changes in surface UV radiation from Estimated changes in surface UV radiation from 1979 to 1992:1979 to 1992:

Ozone DepletionOzone Depletion

The link between man-made chemical The link between man-made chemical emissions and depletion of the stratospheric emissions and depletion of the stratospheric ozone layer was discovered starting in the ozone layer was discovered starting in the mid-1970s.mid-1970s.

The most important step in preventing The most important step in preventing ozone depletion:ozone depletion:

Montréal ProtocolMontréal Protocol on Substances that on Substances that Deplete the Ozone Layer (1987)Deplete the Ozone Layer (1987)

Montréal ProtocolMontréal Protocol

The The Montréal ProtocolMontréal Protocol and later and later amendments required a phaseout of amendments required a phaseout of production and consumption of ozone-production and consumption of ozone-depleting chemicals.depleting chemicals.

The Montréal Protocol has been ratified by The Montréal Protocol has been ratified by over 180 nations.over 180 nations.

In the US, the Montréal Protocol was In the US, the Montréal Protocol was implemented in the provisions of the Clean implemented in the provisions of the Clean Air Act of 1990.Air Act of 1990.

Montréal ProtocolMontréal Protocol

Predicted Predicted Effects of Effects of the the Montréal Montréal Protocol Protocol

Montréal ProtocolMontréal Protocol To facilitate international cooperation in To facilitate international cooperation in

reducing production of ozone-depleting reducing production of ozone-depleting substances, the Montréal Protocol:substances, the Montréal Protocol:– allowed trading of emission reduction credits allowed trading of emission reduction credits

between countries.between countries.– established a Multilateral Fund to assist established a Multilateral Fund to assist

developing countries in the transition toward developing countries in the transition toward CFC substitutes.CFC substitutes. India’s annual consumption of refrigerators is India’s annual consumption of refrigerators is

expected to climb from 6 million in 1989 to 80 million expected to climb from 6 million in 1989 to 80 million in 2010, so its participation in the Montréal Protocol is in 2010, so its participation in the Montréal Protocol is crucial. crucial.

India ratified the agreement in 1992.India ratified the agreement in 1992.

Policy Changes in the U.S.Policy Changes in the U.S.

The Clean Air Act of 1990 ended production The Clean Air Act of 1990 ended production of CFCs on December 31, 1995.of CFCs on December 31, 1995.

Rather than calling for an abrupt ban on Rather than calling for an abrupt ban on production, policies were designed to be production, policies were designed to be more cost-effective.more cost-effective.

Policy Changes in the U.S.Policy Changes in the U.S. Cost-effective provisions:Cost-effective provisions:

– Congress enacted an excise tax on production of Congress enacted an excise tax on production of ozone-depleting chemicals. The tax was gradually ozone-depleting chemicals. The tax was gradually raised over time.raised over time.

– Allowances were issued to producers of ozone-Allowances were issued to producers of ozone-depleting chemicals. Over time the number of depleting chemicals. Over time the number of allowances was reduced.allowances was reduced.

– The 1990 Clean Air Act called for a national recycling The 1990 Clean Air Act called for a national recycling program for CFCs. Existing supplies of CFCs could still program for CFCs. Existing supplies of CFCs could still be legally used.be legally used.

Policies like these provided incentives for the Policies like these provided incentives for the development of safer alternatives to ozone-development of safer alternatives to ozone-depleting chemicals.depleting chemicals.

Costs and Benefits of the CFC PhaseoutCosts and Benefits of the CFC Phaseout

The EPA estimated (in 1987) that the costs The EPA estimated (in 1987) that the costs of phasing out CFCs would be $27 billion of phasing out CFCs would be $27 billion through 2075.through 2075.– For example, the value of CFCs in air-For example, the value of CFCs in air-

conditioning products was estimated to be conditioning products was estimated to be $10.9 billion.$10.9 billion.

The EPA estimated that the benefits of The EPA estimated that the benefits of eliminating CFCs (value of health effects eliminating CFCs (value of health effects and crop damage averted) would be $6.5 and crop damage averted) would be $6.5 trillion.trillion.