Zeotropic mixture harmful effects that hydrochlorofluorocarbons (HCFC) and chlorofluorocarbons (CFC) have on the ozone layer and global warming. Researchers have focused on using new mixtures that have the same properties as past refrigerants to phase out harmful halogenated substances, in accordance to the Montreal Protocol and Kyoto Protocol. For example, researchers found that zeotropic mixture R-404A can replace R-12, a CFC, in household refrigerators. However, there are some technical difficulties for using zeotropic mixtures. This includes leakages, as well as the high temperature glide associated with substances of different boiling points, though the temperature glide can be matched to the temperature difference
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