According to the Environment News Service (ENS), the 1987 Montreal Protocol on Substances That Deplete the Ozone Layer, a protocol to the 1985 Vienna Convention for the Protection of the Ozone Layer, achieved universal ratification this week when the prime minister of Timor-Leste ratified the Protocol. This is the first time ever that a multinational environmental agreement has gained universal ratification. Thanks to the legal regime set up by the Vienna Convention and the Montreal Protocol (with its subsequent amendments), which in short phases out a number of ozone-depleting substances, the size of the hole in the ozone layer has largely been stabilised. Because of this, the Vienna Convention and the Montreal Protocol have been widely hailed as a success story of international environmental law – rightly so. Let us hope that some of the success will rub off on the Copenhagen climate negotiations in December.