Recent changes in summer Greenland blocking captured by none of the CMIP5 models
Recent studies note a significant increase in highpressure blocking over the Greenland region (Greenland Blocking Index, GBI) in summer since the 1990s.
Such a general circulation change, indicated by a negative trend in the North Atlantic Oscillation (NAO) index, is generally highlighted as a major driver of recent surface melt records observed on the Greenland Ice Sheet (GrIS).