How old is arctic sea ice

Ice less than a year old dominated the Arctic. Over time, sea ice that survives the summer melt grows both thicker and less salty, which makes it more resistant to melt and storm-induced disintegration than thin, first-year ice. Historically, a looping current north of Alaska, known as the Beaufort Gyre, acted as a nursery for young ice where it could recirculate, thicken, and grow.

Historically, ice growth in the Beaufort Gyre roughly offset the flow of ice out of the Arctic via the Fram Strait east of Greenland. In the past decade, however, summers in the southern portion of the gyre have been too warm for sea ice to survive.

Old ice continues to exit the Arctic through Fram Strait, but very little is rebuilt. Perovich, D. Sea ice. Climate Time Machine.

Travel through Earth's recent climate history and see how increasing carbon dioxide, global temperature and sea ice have changed over time. Eyes on the Earth. Global Ice Viewer. Earth's ice cover is shrinking.

Estimates of past sea ice extent suggest that this decline may be unprecedented in at least the past 1, years. Because sea ice is highly reflective, warming is amplified as the ice decreases and more sunshine is absorbed by the darker underlying ocean surface. Sea ice in the Antarctic showed a slight increase in overall extent from to , although some areas, such as that to the west of the Antarctic Peninsula experienced a decrease.

Short-term trends in the Southern Ocean, such as those observed, can readily occur from natural variability of the atmosphere, ocean and sea ice system. Changes in surface wind patterns around the continent contributed to the Antarctic pattern of sea ice change; ocean factors such as the addition of cool fresh water from melting ice shelves may also have played a role. However, after , Antarctic ice extent began to decline, reaching a record low within the 40 years of satellite data in , and remaining low in the following two years.

Find out about the Royal Society's latest work on energy, environment and climate. Skip to content You currently have JavaScript disabled in your web browser, please enable JavaScript to view our website as intended. Why is Arctic sea ice decreasing while Antarctic sea ice is not?

Climate change: evidence and causes.