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Max Planck Encyclopedias of International Law – Ozone Layer, International Protection


The 1987 Montreal Protocol on Substances that Deplete the Ozone Layer and its underlying framework convention, the 1985 Vienna Convention on the Protection of the Ozone Layer, solved the first great threat to the global atmosphere by putting the ozone layer on the path to recovery by about 2060.

Globally, the Montreal Protocol’s success in phasing out Ozone Depleting Substances has prevented an estimated 19.1 million non-melanoma cancer cases, 1.5 million melanoma cases, 129 million eye cataracts, and 333,500 cancer fatalities over the period 1987–2060. Total quantified benefits are estimated at US$459 billion, with estimated costs at US$224 billion (see Smith et al., 1997). This does not include the significant mitigation of climate change the Montreal Protocol has provided (see Velders et al. 2007).

The 2016 Kigali Amendment to the Montreal Protocol to phase down HFCs will also contribute significant additional climate mitigation and avoid up to 0.5°C of warming through the end of the century (Xu et al. 2013). Additional efforts to promote the energy efficiency of cooling equipment will provide still more climate protection (see Dreyfus et al. 2020).

The Max Planck Encyclopedias of International Law’s updated Ozone Layer, International Protection (2021) entry, by IGSD’s Dr. Stephen O. Andersen, Durwood Zaelke, Kristen N Taddonio, Richard Ferris, and Dr. Nancy J. Sherman, details the ins and outs of what is widely considered the world’s most successful environmental treaty, the Montreal Protocol. The entry provides detailed analysis of the Protocol’s objectives, chemicals covered, adjustments and amendments, assessment panels, and many other aspects.

The entry is available for open access here.