Quantifying changes in Earth’s ice sheets, and identifying the climate drivers, is central to improving sea-level projections. We provide unified estimates of grounded and floating ice mass change from 2003 to 2019 using NASA’s ICESat and ICESat-2 satellite laser altimetry. Our data reveal patterns likely linked to competing climate processes: Ice loss from coastal Greenland (increased surface melt), Antarctic ice shelves (increased ocean melting), and Greenland and Antarctic outlet glaciers (dynamic response to ocean melting), was partially compensated by mass gains over ice sheet interiors (increased snow accumulation). Losses outpaced gains, with grounded-ice loss from Greenland (200 Gt a$^{-1}$) and Antarctica (118 Gt a$^{-1}$) contributing 14 mm to sea level. Mass lost from West Antarctica’s ice shelves accounted for over 30% of that region’s total.