Case Study 1: The Ozone Hole — When Correction Happened Fast
The ozone hole correction is the gold standard for fast scientific-policy response. From discovery to binding international treaty in approximately two years. This case study analyzes why.
Timeline
| Year | Event |
|---|---|
| 1974 | Molina and Rowland publish theory linking CFCs to ozone depletion |
| 1985 | British Antarctic Survey discovers the ozone hole — 40% depletion |
| 1986 | NASA confirms ozone hole with satellite data |
| 1987 | Montreal Protocol signed — binding international agreement to phase out CFCs |
| 1989 | Montreal Protocol enters into force |
| 1996 | Developed countries complete CFC phase-out |
The Six-Variable Analysis
| Variable | Assessment | Score |
|---|---|---|
| Evidence clarity | Extremely high — visible in satellite data, confirmed by ground measurements | Very favorable |
| Switching cost | Moderate — CFC alternatives existed (HFCs, HCFOs) | Favorable |
| Defender power | Moderate — CFC industry had commercial interests but was outweighed by public concern | Favorable |
| External evidence | Strong — independent satellite confirmation | Very favorable |
| Correction mode | Circumvention — the mechanism was well-understood, rendering "it might not be CFCs" objections obsolete | Very favorable |
| Crisis | High — existential threat (skin cancer, crop damage, ecosystem collapse) | Very favorable |
All six variables favored fast correction. The result: one of the fastest scientific consensus → policy action transitions in history.
Why Climate Change Is Different
The ozone case is often compared to climate change. The comparison reveals why structural variables, not science quality, determine correction speed:
| Variable | Ozone | Climate Change |
|---|---|---|
| Evidence clarity | Dramatic, visible hole | Gradual trend requiring statistical analysis |
| Switching cost | Moderate (chemical substitutes) | Very high (entire energy infrastructure) |
| Defender power | Moderate (one industry) | Very high (fossil fuel industry + geopolitics) |
| External evidence | Independent satellite confirmation | Multiple lines, but all statistical |
| Correction mode | Circumvention (mechanism clear) | Persuasion (mechanism debated in public discourse) |
| Crisis | Acute, existential | Chronic, gradual |
The science is equally strong. The structural conditions are dramatically different. The correction speed difference follows the prediction.
Discussion Questions
- Could the ozone response model be applied to other environmental issues? What structural conditions would need to change?
- DuPont (a major CFC manufacturer) eventually supported the Montreal Protocol. Why? What changed their incentive calculation?
- Is the Montreal Protocol's success evidence that international scientific cooperation works — or is it an exception that proves the rule?
References
- Molina, M. J. & Rowland, F. S. (1974). "Stratospheric Sink for Chlorofluoromethanes." Nature, 249, 810–812. (Tier 1)
- The Montreal Protocol text and implementation history are documented by the UN Environment Programme. (Tier 1)