The Ozone Story Formation of the ozone layer

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The Ozone Story • Formation of the ozone layer • Why We Care •

The Ozone Story • Formation of the ozone layer • Why We Care • Ozone Threats: CFCs • Early warnings • Building a scientific consensus • “Nature” of Action • Lessons learned from the ozone story

Modern Impacts to Ozone CFCs Chlorofluorocarbons • What are they? • How do they

Modern Impacts to Ozone CFCs Chlorofluorocarbons • What are they? • How do they impact the ozone layer?

Development of CFCs 1928: Du. Pont scientists develop CFCs “ideal compounds” for refrigerants and

Development of CFCs 1928: Du. Pont scientists develop CFCs “ideal compounds” for refrigerants and propellants WHY? ?

Refrigeration prior to CFCs http: //www. history. com/exhibits/modern/fridge. html

Refrigeration prior to CFCs http: //www. history. com/exhibits/modern/fridge. html

CFCs as Refrigerants CFCs vs Traditional Refrigerants (ammonia, sulfur dioxide, methyl chloride)

CFCs as Refrigerants CFCs vs Traditional Refrigerants (ammonia, sulfur dioxide, methyl chloride)

CFCs as Propellants • Extremely stable or “inert” • Light weight What do these

CFCs as Propellants • Extremely stable or “inert” • Light weight What do these features suggest? ?

Marketing AND Questioning of CFCs 1958: Du. Pont releases CFCs on the market commercially

Marketing AND Questioning of CFCs 1958: Du. Pont releases CFCs on the market commercially 1971: James Lovelock speculates that CFCs put into the atmosphere may still be present 1973: Mario Molina and F. Sherwood Roland investigate

Original Research 1974: Rowland Molina Cl C F Cl F UV + radiation F

Original Research 1974: Rowland Molina Cl C F Cl F UV + radiation F + Cl“free radical”

Cl Cl- + O 3 (ozone) “free radical” + Cl. O “Free Radicals”… O

Cl Cl- + O 3 (ozone) “free radical” + Cl. O “Free Radicals”… O + Cl. O O 2 + Cl“free radical” O 2 http: //video. google. com/videoplay? docid=5820549884785529675&q=stratosphere+ozone&total=26&start=0&num=10&so=0&type=search&plindex=5

In the news… 1974: Molina and Rowland publish their hypothesis in Nature. New York

In the news… 1974: Molina and Rowland publish their hypothesis in Nature. New York Times runs front page Du. Pont responds with study showing that CFCs in troposphere are benign 1975: 200% increase in CFC use from 1968, only eight years

High Risk and Political Savvy 1979: The FDA, EPA ban non-essential uses of CFCs

High Risk and Political Savvy 1979: The FDA, EPA ban non-essential uses of CFCs ! First time substance EVER banned without direct proof of harm!!! 1982: 20 other countries join US in ban of CFCs

Scientific Controversies 1982: British science teams in Antarctica observe 20% decline in O 3

Scientific Controversies 1982: British science teams in Antarctica observe 20% decline in O 3 layer US scientists relying on TOMS (Total Ozone Mapping Spectrometer) measurements from space claim to observe nothing

Scientific Evidence 1983: British scientists observe 30% reduction in ozone layer. US scientists claims

Scientific Evidence 1983: British scientists observe 30% reduction in ozone layer. US scientists claims no reduction. 1985: British observe 50% reduction. US claims no reduction. US re-tests and confirms. WHY THE SCIENTIFIC DISAGREEMENT? ?

TOMS Data (corrected)

TOMS Data (corrected)

Total Ozone, 1978 -1998

Total Ozone, 1978 -1998

Monthly Average for Total Ozone over Antarctica, 1955 -1995 Based on British measurements from

Monthly Average for Total Ozone over Antarctica, 1955 -1995 Based on British measurements from weather balloons

Patterns of Loss • Poles have greater ozone loss than other regions: – Colder

Patterns of Loss • Poles have greater ozone loss than other regions: – Colder – Wetter – more vapor formation – Polar vortex • Particularly severe in polar spring (October) • Ozone loss extends beyond Antarctica and Arctic Polar regions

Understanding the Science 1986: Du. Pont scientists continue to argue that tropospheric ozone (smog)

Understanding the Science 1986: Du. Pont scientists continue to argue that tropospheric ozone (smog) will migrate up and “fill the ozone hole” in the stratosphere Why doesn’t this theory fly?

Montreal Protocol Landmark 1987: 2 yrs of intensive research reveal that ozone hole is

Montreal Protocol Landmark 1987: 2 yrs of intensive research reveal that ozone hole is anthropogenic 1988: UN hold meeting in Montreal 45 Nations sign to reduce CFC use by 50% by year 2000. Developing countries’ efforts would be ‘subsidized’

Two steps forward… 1990 - Follow up meetings result in: 1992: Industrialized nations: total

Two steps forward… 1990 - Follow up meetings result in: 1992: Industrialized nations: total ban by 2000 Developing nations: ban by 2010, with assistance from developed nations US agrees to complete phaseout by 1996; Du. Pont to halt production by 1997 1995: Rowland Molina receive Nobel Prize

One step back… 1995: Congress challenges ozone science: Junk science gains credibility despite scientific

One step back… 1995: Congress challenges ozone science: Junk science gains credibility despite scientific consensus of anthropogenic causes of O 3 depletion 1996: Ban begins but black market for CFCs appear WHY? CFC substitutes (HFC) break down faster, but still pose problems for ozone depletion

Current Rate of Ozone Depletion • Decrease in rate of ozone depletion (since 1997)

Current Rate of Ozone Depletion • Decrease in rate of ozone depletion (since 1997) • Slowing of buildup of harmful Cl- from CFCs • Ozone hole is still growing, but… Models anticipate restoration of “normal” balance of ozone in stratosphere by 2050

Breakdown of Sources

Breakdown of Sources

Threats to Ozone Remain • Methyl Bromide • Hydrogen fuel sources

Threats to Ozone Remain • Methyl Bromide • Hydrogen fuel sources

Success Story What characteristics define ozone depletion “an environmental success story ? ”

Success Story What characteristics define ozone depletion “an environmental success story ? ”