Emissions trading market in pollution-licenses is more widely applicable than the market in emission-licenses. The international community began the long process towards building effective international and domestic measures to tackle GHG emissions (carbon dioxide, methane, nitrous oxide, hydroflurocarbons, perfluorocarbons, sulphur hexafluoride) in response to the increasing assertions that global warming is happening due to man-made emissions and the uncertainty over its likely consequences. That process began in Rio in 1992, when 160 countries agreed the UN Framework Convention on Climate Change (UNFCCC). The UNFCCC is, as its title suggests, simply a framework; the necessary detail was left to be settled by the
Nitrous oxide used by almost half a million young people at nightspots, festivals, and parties. The legality of that use varies greatly from country to country, and even from city to city in some countries. The major safety hazards of nitrous oxide come from the fact that it is a compressed liquefied gas, an asphyxiation risk, and a dissociative anaesthetic. While relatively non-toxic, nitrous oxide has a number of recognized ill effects on human health, whether through breathing it in or by contact of the liquid with skin or eyes. Nitrous oxide is a significant occupational hazard for surgeons, dentists, and nurses.