Industry and ice

As the Arctic Ocean becomes increasingly ice-free, many countries are eager to tap into previously inaccessible northern resources. Energy companies seek drilling permits for oil and natural gas, and shipping companies hope to ply newly opened sea routes. Given the unpredictable nature of Arctic sea ice, some wonder if operating in the already inhospitable north will be an economically viable effort. Others believe that even if drilling or shipping is not currently viable, the Arctic is changing fast enough that industry in the Arctic is here to stay. Continue reading

How low is low?

extent graph

Sea ice extent reached a new record low on August 27, 2012 and continued to decline. The last six years have seen minimum sea ice extents below the two standard deviation range of the data. The graph above shows Arctic sea ice extent as of August 13, 2012, along with daily ice extent data for the previous five years. 2012 is shown in blue, 2011 in orange, 2010 in pink, 2009 in navy, 2008 in purple, and 2007 in green. The gray area around the average line shows the two standard deviation range of the data.


Satellite observations since 1979 show that sea ice melted to its lowest extent in the satellite record, during August 2012 . As of this post date, the ice continues to melt, with two to three weeks left before the days shorten enough for the ice extent to begin to expand through the winter. Readers often write to us asking what such records really mean. How far from normal is this year’s record low, and how do scientists decide what is normal? Continue reading

Do satellites sometimes see ice where there isn’t any?

Readers often ask us, “Why does your sea ice map show sea ice where there is none?” Sometimes our Daily Sea Ice Extent images show sea ice in a particular area, but when readers who live in those areas look out their windows, they see open water—or they even may see ice where our maps show open water. This occurs most frequently along rivers or near coasts. Why does this happen?

Ups and downs of passive microwave

Photograph of Qaanaaq, a small town on the Greenland coast

The rugged coast near Qaanaaq, Greenland, illustrates the challenge to satellite sensors, which must distinguish between land and ocean signals within the same image. Credit: Andy Mahoney

These discrepancies are most often caused by the resolution of the satellite sensor. NSIDC relies on passive microwave sensors to compile daily sea ice maps. These sensors have the advantage of being able to see through the Arctic’s cloudy weather and capture surface data even during long, dark winters, making them ideal for tracking sea ice. The disadvantage, however, is that passive microwave sensors often have low spatial resolution. The sensors collect data in “footprints” that are up to 50 to 70 kilometers (31 to 44 miles) in diameter. Continue reading

What does seeping methane mean for the thawing Arctic?

Photograph of bubbling methane melting a hole through lake ice

Bubbling methane melted a hole in the ice of this otherwise frozen lake in the Brooks Range, Alaska, in April 2011. Credit: Katey Walter Anthony

As people watch the decline of Arctic sea ice, the most obvious sign of climate warming in that region, scientists are noting other signs of change, like methane seeping out of the ground as permafrost thaws and glaciers melt across the Arctic. Scientists suspected these methane seeps existed, but no one had measured how much methane was escaping—until recently. Continue reading

Is Arctic sea ice back to normal?

Arctic sea ice was at record highs in the Bering Sea this spring, and near the long-term average for the Arctic as a whole. But much of that ice was spread thinly across the ocean, and is now melting quickly. This image, from the NASA Moderate Resolution Imaging Spectroradiometer (MODIS), shows sea ice in Bristol Bay off of Alaska, on April 24, 2012. |Credit: {a href=}NASA Earth Observatory{/a} image by Jesse Allen|{a href=}High Resolution Image{/a}

In April, average ice extent in the Arctic Ocean was right near the long-term average for the month. Ice extent even reached a near-record high in the Bering Sea, and still remains above average for that region. Does this mean that the Arctic sea ice has stopped declining? Is it starting to recover?

Unfortunately, scientists say no—and they are not surprised to see such a short upward bump in ice extent. “This does not indicate that the Arctic sea ice is recovering,” said Marika Holland, a sea ice expert at the National Center for Atmospheric Research (NCAR). Instead, the higher ice extent this year compared to recent years likely just reflects different weather this winter compared to last winter.  “Sea ice exhibits large natural variability due to year-to-year variations in weather,” she said. Continue reading