Heading towards the summer minimum ice extent

Figure 1. This graph shows Arctic sea ice extent for spring and summer months. Light blue indicates the ice extent this year, dark blue shows ice in 2010, and green indicates ice extent during 2007, which was the record low year for Arctic sea ice. The gray line shows the 1979 to 2000 average ice extent, while the gray area around the gray line shows the standard deviation range for the data, which represents the range of normal variability. Credit: NSIDC

So far this summer, Arctic sea ice has been melting at a record pace. Satellite data, which go back to 1979, show that ice extent is currently lower than it was at the same time in 2007, the year that went on to shatter all previous records for low ice extent in September, the end of the melt season (Figure 1). It is not yet clear if the ice will hit a new record low this September. But whether or not the ice extent sets another record, Arctic sea ice is continuing its long-term decline, a trend that researchers say is related to warming temperatures in the Arctic.

This time of year, we receive a lot of questions about the upcoming sea ice minimum. What is it and why does it matter? Continue reading

What about sea ice in winter?

Researchers take measurements of the physical properties of sea ice in Fram Strait, in the Canadian Arctic. Thinner sea ice melts away faster in the summer compared to older, thicker ice. Credit: Angelika Renner

Arctic sea ice has most likely frozen to its maximum extent for the winter. This event marks the turning point between winter and spring for sea ice, and may affect the amount of ice that will remain by end of summer. In early April, NSIDC scientists will talk about what this year’s maximum signifies for the upcoming summer. Meanwhile, readers are asking how the ice cover this year is different from the ice cover in years past.

Arctic sea ice grows each winter, hitting its annual maximum sometime in March. When the sun returns to the Arctic in the spring, the air warms up and the ice starts to melt. The ice retreats through the warmer summer months, hitting its lowest point sometime in September. Although scientists watch the sea ice year-round, they pay attention to the highest and lowest extents of the year as indicators of the overall health of the sea ice. Continue reading