International Day for the Preservation of the Ozone Layer of the hole in the ozone layer was observed 30 years after the protocol was signed. Due to the nature of the gases responsible for ozone depletion their chemical effects are expected to continue for between 50 to 100 years. International Day for the Preservation of the Ozone Layer September 16 was designated by the United Nations General Assembly as the International Day for the Preservation of the Ozone Layer. This designation had been made on December 19, 2000, in commemoration of the date, in 1987, on which nations signed the Montreal Protocol on Substances that Deplete the Ozone Layer.
Tourism in Antarctica tourists that come to visit Antarctica. The Environmental Protocol to the Antarctic Treaty does not specifically address tourism, but its provisions go some way to minimising the adverse impacts of tourists because, once ratified, the protocol is legally binding over all visitors to the Antarctic, whether on government or private trips. In 1994 the Treaty countries made further recommendations on tourism and non-government activities. This "Guidance for Visitors to the Antarctic" is intended to help visitors become aware of their responsibilities under the treaty and protocol. The document concerns the protection of Antarctic wildlife and protected areas, the respecting of