evidence: "This is an important finding and corroborates the suspicion that the ‘missing warming’ in the ice cores is due to the fact that the cores end before the strong warming sets in," said climate scientist Martin Stendel of the Danish Meteorological Institute, who wasn’t part of the research. The ice cores are used to make a chart of proxy temperatures for Greenland running from the year 1000 to 2011. It shows temperatures gently sloping cooler for the first 800 years, then wiggling up and down while sloping warmer until a sharp and sudden spike hotter from the 1990s on. One scientist compared it to a hockey stick, a description used for other long-term temperature data showing climate change. READ MORE: Greenland suspends oil exploration because of climate change The jump in temperature after 1995 is so much larger than pre-industrial times before the mid-19th century that there is "almost zero" chance that it is anything but human-caused climate change, Hoerhold said. The warming spike also mirrors a sudden rise in the amount of water running off from Greenland’s melting ice, the study finds.