As to Why for Greenland...

The study also notes that global warming is greatest at higher latitudes near the poles. This is because when the Earth warms, snow and ice melt, uncovering darker land and ocean surfaces. Instead of the once-white surface that reflected solar rays back into space, the darker surfaces now absorb more energy from the sun.

That explains the much larger relative temperature rise in Greenland and gives more credence to my mutterings about Greenland's future ecology. I really think that people ought to consider highland properties - those above the maximum possible water rise of 150 ft/45 m) in Greenland...;)