| Year / Adoption | 1985 (Vienna, 22 March 1985) | 1987 (16 September 1987) | 2016 (15 October 2016, Kigali, Rwanda) |
| Entry into Force | 22 September 1988 | 1989 (implied under protocol system) | 1 January 2019 |
| Why Introduced | Scientific concern about ozone depletion; need for cooperation amid uncertainty | Strong scientific evidence (Antarctic ozone hole) demanded concrete action | Rising HFC use after ODS phase-out causing climate change |
| Objective | Promote global cooperation, research, monitoring, data sharing | Phase-out ozone-depleting substances (ODS) | Phase-down HFCs to address climate change |
| Nature | Non-binding framework convention | Legally binding treaty | Legally binding amendment under Montreal Protocol |
| Focus Area | Understanding and addressing ozone depletion | Eliminating ODS (CFCs, HCFCs, halons, etc.) | Reducing high GWP greenhouse gases (HFCs) |
| Type of Chemicals | No direct control | Ozone-depleting substances (ODS) | Greenhouse gases (HFCs) |
| Approach | Cooperation, research, information exchange | Time-bound targets with differentiated responsibilities | Gradual reduction (80–85% by ~2047) |
| Key Mechanism | Scientific collaboration, meetings every 3 years | Trade controls, reporting, compliance system, licensing | Climate-oriented extension of Montreal framework |
| Institutional Setup | Framework for future treaties | Ozone Secretariat under UNEP, governance via Parties | Uses Montreal Protocol institutional structure |
| Global Coverage | 198 parties (universal ratification by 2009) | 198 parties (197 states + EU) | 170+ countries + EU (as of 2025) |
| Historical Significance | First global agreement acknowledging ozone depletion problem | First treaty to enforce global environmental regulation successfully | Integrates ozone regime with climate change mitigation |
| Progress Achieved | Built global awareness and cooperation | 98–99% ODS phased out, ozone recovery underway | Can prevent ~0.5°C warming by 2100 |
| Impact if Absent | No coordinated global response | Ozone depletion would have worsened drastically | Uncontrolled HFC growth → major climate threat |
| Overall Role | Foundation stage (Problem identified) | Action stage (Problem solved) | Climate stage (Side-effects addressed) |