NASA has issued a warning about climate change after a new island appeared in southeastern Alaska. Over the past four decades, satellites captured images showing a melting glacier forming a lake that has surrounded a mountain called Prow Knob. This mountain, once covered by the Alsek Glacier’s ice, is now completely separated by water, making it a true island.
Prow Knob covers about two square miles and was part of a larger glacier until the ice gradually melted. These “proglacial lakes” are formed when meltwater fills the space left by retreating glaciers. NASA estimates this separation happened between mid-July and early August of this year.
The Alsek Glacier has retreated more than five kilometers since the 1980s, doubling the size of Alsek Lake. This change signals worsening impacts of climate change, as higher temperatures speed up glacier melting, reshaping coastlines and threatening ecosystems.
