Melting of the Canadian Arctic Archipelago
The melting of the two large ice sheets (Antarctica and Greenland) account for about 40% of the current rise in sea level. The other 60% comes from the melting of mountain glaciers and ice caps. See Mark F. Meier, et al., “Glaciers Dominate Eustatic Sea-Level Rise in the 21st Century,” 317 Science 1064-67 (August 24, 2007) (full text; free registration required). The 36,563 islands that make up the Canadian Arctic Archipelago, which cover 1,424,500 square kilometers (about 550,000 square miles), represent a substantial part of the contribution to that rise.
In a letter published online in April, Alex S. Gardner, et al., “Sharply Increased Mass Loss from Glaciers and Ice Caps in the Canadian Arctic Archipelago,” 473 Nature 357-60 (May 19, 2011) (abstract; article behind paywall), Alex S. Gardner shows that the melt from the Canadian Arctic Archipelago from 2007 to 2009 was the single largest contributor to global sea level rise outside of the two ice sheets. From 2004-06 the Canadian Arctic Archipelago lost an average of 31 billion tons (gigatons) of ice per year (± 8 Gt yr−1). The rate dramatically rose for the period from 2007-09 to 92 billion tons per year ( ± 12 Gt yr−1).
The maps above, from NASA’s Earth Observatory, show ice loss from surface melting for the northern portion of the archipelago from 2004–2006 (left) and 2007–2009 (right). Blue indicates ice gain, and red indicates ice loss.