Consider that even with a rise of only 0.8ºC so far, the planet has experienced record-high temperatures, more extreme weather events, and substantial melting of the Greenland ice sheet, which contains enough water to cause a seven-meter rise in sea levels. In Copenhagen, the pleas of representatives of small island states (some of which will cease to exist if sea levels continue to rise) for a target of 1.5ºC went unheeded, essentially because world leaders thought the measures required to meet such a target were politically unrealistic.