Greenhouse gas emissions from wetlandsGreenhouse gas emissions from wetlands of concern consist primarily of methane and nitrous oxide emissions. Wetlands are the largest natural source of atmospheric methane in the world, and therefore remain a major area of concern with respect to climate change. They contribute approximately 167 Tg of methane to the atmosphere per year. Wetlands account for approximately 20 percent of atmospheric methane through emissions from soils and plants.
Nitrous oxideNitrous oxide (dinitrogen oxide or dinitrogen monoxide), commonly known as laughing gas, nitrous, nitro, or nos, is a chemical compound, an oxide of nitrogen with the formula N2O. At room temperature, it is a colourless non-flammable gas, and has a slightly sweet scent and taste. At elevated temperatures, nitrous oxide is a powerful oxidiser similar to molecular oxygen. Nitrous oxide has significant medical uses, especially in surgery and dentistry, for its anaesthetic and pain-reducing effects.
Rhythm changesRhythm changes are a common 32-bar chord progression in jazz, originating as the chord progression for George Gershwin's "I Got Rhythm". The progression is in AABA form, with each A section based on repetitions of the ubiquitous I–vi–ii–V sequence (or variants such as iii–vi–ii–V), and the B section using a circle of fifths sequence based on III7–VI7–II7–V7, a progression which is sometimes given passing chords. This pattern, "one of the most common vehicles for improvisation," forms the basis of countless (usually uptempo) jazz compositions and was popular with swing-era and bebop musicians.
