Retreating Arctic ice is considered a key indicator of the pace of global warming by environmentalists, and one that could have devastating knock-on repercussions for the wider climate, including warmer oceans and rising sea levels.

CNN: Arctic melt worse than predictions

Studies like 'Ice Bridge' are key.

CNN: NASA flights will study Antarctic ice changes

Nonetheless, the researchers say, thinning has intensified at key locations where ice streams enter the ocean.

BBC: Laser satellite records ice loss