Read here. As Earth's climate has cycled through changes over the geological time, Greenland has faithfully recorded the changes. The glaciers and ice sheets responded accordingly, thus confirming that major climate change (including melting glaciers) will occur whether CO2 levels are low or high.
"Even in ice-cold Greenland, Holocene temperatures followed much the same temporal pattern observed in other parts of the world, as did the advance and retreat modes of its local glaciers, with maximum glacier extensions occurring during the coldest period of the current interglacial (the Little Ice Age). As a result, it was only to be expected that once the millennial-scale oscillation of temperature bottomed out and began to rise again, the result would be a significant warming and recession of local glaciers, irrespective of anything the air's CO2 content might do..."
