On the cover

This image, based on satellite observations from September 2016, shows the edge of the Larsen C Ice Shelf in Antarctica, in the region from which an iceberg larger than Delaware would calve in July 2017. Although calving is more dramatic, ice shelves also lose a significant amount of mass through melting from below. To learn more about Antarctic ice-shelf melting, read the article by Catherine A. Vreugdenhil and Bishakhdatta Gayen. (Observational data courtesy of NASA’s Landsat 8 and USGS; data processed by Paul Quast/CC BY 2.0 ; border art adapted from iStock.com/marukopum.)