The global cryosphere—all of the areas with frozen water on Earth—shrank by about 87,000 square kilometers (about 33,000 square miles, an area about the size of Lake Superior) per year on average between 1979 and 2016, as a result of climate change, according to a new study. This research is the first to make a global estimate of the surface area of the Earth covered by sea ice, snow cover and frozen ground.