Researchers can measure ice thickness by drilling holes in the sea ice. But the method is not a practical way to measure thickness over the millions of square miles of Arctic sea ice. Image courtesy of Martin Hartley

NSIDC reports ice extent, a two-dimensional measure of the Arctic Ocean’s ice cover. But sea ice extent tells only part of the story: sea ice is not all flat like a sheet of paper. While freshly formed ice might not be much thicker than a few sheets of paper, the oldest, thickest ice in the Arctic can be more than 15 feet thick—as thick as a one-story house. Scientists want to know not just how far the ice extends, but also how deep and thick it is, because thinner ice is more vulnerable to summer melt. Continue reading →