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
Canada and the Kyoto Protocol of compliance has been estimated 20 times lower. States for which the emissions are not covered by the Kyoto Protocol (the US and China) have the largest emissions, being responsible for 41% of the Kyoto Protocol. China's emissions increased by over 200% from 1990 to 2009. Canadian Council of Chief Executives VP John Dillon argued (2011-11-22) that a further extension of Kyoto would not be effective as many countries, not just Canada, were not on track to meet their 1997 Kyoto commitments to reduce emissions. He called for a comprehensive, long-term global agreement that includes major emitters like the US,