evidence: 1968 - Scientist predicts melting ice caps [...] What they found was alarming. The Greenland ice sheet, parts of the Antarctic ice sheet, and Arctic sea ice are melting at rates that are unprecedented in the last 10,000 years. [...] The Greenland ice sheet is also melting at an accelerating rate, and could add a further seven metres to sea levels. Models show that the Greenland ice sheet will collapse when the Earth warms to 1.5°C above pre-industrial levels, which could happen as soon as 2030.