“Processing spaceborne digital imagery to measure changes in surface elevation requires enormous computation power,” said UNBC professor and Hakai affiliate Dr. Brian Menounos, the Canada Research Chair in Glacier Change. “We needed an equivalent of about 584 modern computers running for about a year to derive these elevation models. Looked at another way, the generation of the elevation models required over five million compute hours.”
The computations are part of a paper published in the April 29 issue of Nature that found that between 2000 and 2004, glaciers lost 227 gigatonnes of ice per year, but between 2015 and 2019, this rate increased to 298 gigatonnes per year. A gigatonne is equivalent to one billion tonnes. Loss of water from glaciers represents about 21 percent of the observed rise in sea levels over the last 20 years – some 0.74 millimetres a year.