Thwaites Glacier is rapidly melting and could trigger multi-foot global sea-level rise, threatening coastal regions and potentially destabilizing West Antarctica.
He knew Greenland's melting ice better than anyone. Then he disappeared into it.
Konrad 'Koni' Steffen disappeared from the Greenland ice sheet on August 8, 2020, after retrieving climate data; his presumed death remains mourned and unexplained.