Climate Number: 179 Cubic Miles
Many of Earth’s great ice masses, which collectively form the cryosphere, are floating on ocean surfaces. There are three main collections of floating ice: the Arctic sea ice, the Antarctic ice shelves and the Antarctic sea ice. All three components have seasonal fluctuations, with the Antarctic sea ice showing the most dramatic differences between winter and summer extents. The Antarctic ice shelves are the edges of the Antarctic continent’s ice sheets that extend out onto the oceans. Every year, in each hemisphere’s respective summer, large portions of the floating ice either melts or breaks off into chunks known as icebergs that float off into the open ocean before melting. In a world with a static climate, about the same amount of ice that melts every summer would refreeze the following winter. Between 1994 and 2004, however, there was on average about 179 cubic miles less floating ice each year, indicating an overall loss of ice and a warming of the oceans and atmosphere. While this loss of floating ice contributes only minimally to sea level rise, such losses may impact ocean salinity, heat distribution and mixing. These changes may in turn lead to changes in the ocean current system, which may have other ramifications for the climate system.
For Comparison: 179 cubic miles is about the same size as three million Great Pyramids of Giza.
Seasons: Winter, Spring, Summer, Fall
Source: Shepherd, A et al. “Recent loss of floating ice and the consequent sea level contribution.” Geophysical Research Letters 37 (2010): L13503.
