Floating sea ice covers about 11 million square miles of Earth’s oceans in the Arctic and Antarctic regions. It plays an important role in regulating climate and is critical for many animals. Glaciers and Ice sheets cover around 10 percent of the land area on Earth. Every continent except Australia is partially covered in ice.
Despite its extent and importance, the nature of the cryosphere makes it difficult to visit, study and understand. Because of the remote and harsh conditions throughout most of the polar regions, scientists who study them often have to rely on data collected from space for research.
The images taken by satellites and astronauts provide critical information for understanding the rapidly changing climate near the poles, but they also deliver some surprisingly beautiful, strange and intriguing images. We’ve collected some of the best here.
Above: The Wilkins ice shelf on the Antarctic Peninsula dramatically broke apart in February 2008. In the image above, captured by the Taiwanese satellite Formosat-2, big pieces of the ice shelf float in a frozen matrix of smaller bits of ice. Some of the larger chunks are several hundred yards long. The image was made from near-infrared, infrared and green wavelengths reflected by the ice.
Below: This image from NASA’s Terra satellite, taken in November 2009, gives a wider view of the event.
Off the northeastern coast of Greenland, ocean currents swirl sea ice into intricate and beautiful patterns. This image was captured in 2006 by the MODIS instrument aboard NASA’s Terra satellite.
The Sea of Okhotsk sits between Siberia and the Kamchatka Peninsula in far eastern Russia. In the winter, it becomes largely covered by ice. In the image above, captured by the MODIS instrument on NASA’s Terra satellite in February 2007, cold winds from Siberia combine with moist ocean air to form the cloud streets streaming away from the ice.
The image below, captured by the Terra satellite’s ASTER instrument in February 2009, shows sea ice that has tracked currents in the Sea of Okhotsk.
The Hampton and Moran glaciers feed ice into Shokalsky Bay at the northern tip of Alexander Island in this image captured by the USGS-NASA Earth Observing-1 satellite in 2009. The accelerating flow of these and more than 400 other Antarctic Peninsula glaciers is adding to sea-level rise. The icebergs that have calved off these glaciers will eventually move north into warmer waters, where they will melt.
This crack in Pine Island Glacier on the edge of the West Antarctic Ice Sheet was imaged by the ASTER instrument on NASA’s Terra satellite in December 2000. The crack led to the prediction that a major iceberg would break off in less than 18 months. In November 2001, as shown in the sequence below, it did.
Recent research has shown that the melting of Pine Island Glacier is accelerating, and the grounding line, where the ice sheet goes from resting on land to floating on water, is retreating rapidly.
A new study published online Jan. 13 in the Proceedings of the Royal Society A used models to show that the instability of the grounding line could push Pine Island Glacier past a tipping point in the near future. The volume of water held in the entire West Antarctic Ice Sheet is enough to raise global sea level by more than 10 feet.
Sea ice is floating frozen seawater on the ocean’s surface. It covers millions of square miles of ocean near Earth’s poles. Sea ice in the Antarctic melts in the summertime and reforms in the winter. The sea ice shown here is in the Arctic, where some ice persists year-round and is an important factor in global climate. This image was captured by the NASA-USGS Landsat-7 satellite in June 2001.
The Ayles Ice Shelf on Ellesmere Island in the Canadian Arctic archipelago broke away from the island in 2005. The image above, captured by the ASTER instrument on NASA’s Terra satellite in 2006 shows the area a year after the ice sheet broke away. A mosaic of sea ice covers the water along the coastline. Below, the ice sheet is still intact when the satellite imaged it in 2002. The parallel stripes of melt ponds on the ice shelf are a prelude to its demise.
The image above shows the massive B-22 iceberg just beginning to break away from the Thwaites Ice Tongue in the Amundsen Sea in West Antarctica on March 10, 2002. B-22 is around 50 miles long and 38 miles wide. Below, the iceberg has begun moving away two weeks later. The two smaller icebergs to the right of B-22 are pieces of a larger berg named B-21 that broke away in 2001. Both images are natural-color pictures captured by the MISR camera on NASA’s Terra satellite.
The giant iceberg B-10 measured more than 1,000 square miles and was a quarter-mile thick when it broke away from an Antarctic glacier in the late 1980s. It split in two in 1995. The larger piece, shown here near the Drake Passage in September 1999, was still as big as Rhode Island and was named B-10A. In this true-color image captured by the NASA-USGS Landsat 7 satellite, smaller icebergs are seen calving off the edge of B-10A. Some of the bergs floated into shipping lanes and had to be monitored by Landsat and other satellites to avoid collisions.
The mosaic of sea ice in the Bering Strait above was captured by the MODIS imager on NASA’s Aqua satellite in February 2008. The green color of the sea in the bottom left is due to phytoplankton blooming. The scene is constantly shifting as sea ice flows, as can be seen in the image below of the same area, taken by Aqua on Jan. 11, 2010.
This image of the Labrador Sea is a beautiful combination of a range of sizes of sea-ice chunks breaking away from the pack ice along the coast of Newfoundland. It was taken in April 2003 as part of an effort by astronauts aboard the International Space Station to help scientists study events like ice thawing in spring.
A large iceberg that broke away from the Ross Ice Shelf in western Antarctica in 2000 is shown floating in the Ross Sea near the Drygalski Ice Tongue in March 2006. The iceberg, named C-16, crashed into the end of the ice tongue a few days later and knocked off a chunk of the tip. This image was captured by the MODIS instrument on board NASA’s Terra satellite.
