Meltwater on the Langjokull ice cap in Iceland disappearing into a moulin, Iceland, Polar Regions

iceland water melt water melting summer glacier glaciation ice ice cap langjokull glacial retreat retreating recede receding climate change global warming blue ice moulin meltwater outdoors landscape landscapes scenics cold ice caps icecap icecaps nature natural world topography glaciology moulins crevasses polar regions day sinkhole sinkholes sink hole sink holes horizontal