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 dominant. In a vacuum thruster, this may provide a monopropellant specific impulse ("I") of as much as 180 s. While noticeably less than the "I" available from hydrazine thrusters (monopropellant or bipropellant with dinitrogen tetroxide), the decreased toxicity makes nitrous oxide an option worth investigating. Nitrous oxide is said to deflagrate at approximately at a pressure of 309 psi (21 atmospheres). At 600 for example, the required ignition energy is only 6 joules, whereas at 130 psi a 2500-joule ignition energy input is insufficient. In vehicle racing, nitrous oxide (often referred to as just "nitrous") allows the engine to burn