Greenhouse gas systems. Future warming is projected to have a range of impacts, including sea level rise, increased frequencies and severities of some extreme weather events, loss of biodiversity, and regional changes in agricultural productivity. The main sources of greenhouse gases due to human activity are: The seven sources of from fossil fuel combustion are (with percentage contributions for 2000–2004): Carbon dioxide, methane, nitrous oxide () and three groups of fluorinated gases (sulfur hexafluoride (), hydrofluorocarbons (HFCs), and perfluorocarbons (PFCs)) are the major anthropogenic greenhouse gases, and are regulated under the Kyoto Protocol international treaty, which came into force in 2005. Emissions
Nitrous oxide from various types of oils combined with lecithin (an emulsifier), may use nitrous oxide as a propellant. Other propellants used in cooking spray include food-grade alcohol and propane. Nitrous oxide has been used in dentistry and surgery, as an anaesthetic and analgesic, since 1844. In the early days, the gas was administered through simple inhalers consisting of a breathing bag made of rubber cloth. Today, the gas is administered in hospitals by means of an automated relative analgesia machine, with an anaesthetic vaporiser and a medical ventilator, that delivers a precisely dosed and breath-actuated flow of nitrous oxide mixed with