Is an East Antarctic melt probable?

Does melting of the East Antarctic Ice Sheet (EAIS) pose a threat to sea level rise? Studies of the ice melt that fuels sea level rise often focus on the prominent warming and melting of glaciers in Greenland and western Antarctica. The massive East Antarctic Ice Sheet (EAIS) has been largely ignored, until recently. “It’s generally been assumed that it’s so big and so cold that it’s probably immune to some of the warming trends we’ve seen across the planet,” said Chris Stokes, a professor at Durham University. Two recent studies, however, paint a new picture of the world’s thickest, unwavering giant, suggesting the need to look deeper into eastern Antarctica. Continue reading

Arctic melt versus Antarctic freeze: Is Antarctica warming or not?

Photograph of a large tabular iceberg and sea ice near Antarctica

During the short austral summer, much of the sea ice surrounding Antarctica melts, often leaving only the large, tabular icebergs. Credit: NSIDC courtesy Andi Pfaffling

September 2012 was a record-setting month for both of Earth’s poles, but for different reasons: sea ice in the Arctic fell to a record low minimum extent after a summer of melting, while Antarctic sea ice froze to a record high extent during the South Pole winter. Is record Antarctic sea ice canceling out the losses in Arctic ice? And does the record in the south mean that Antarctica is not warming? Continue reading

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

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

Sea ice and the Arctic coast

eroding coast and house in shishmaref, alaska

Like many villages along the Arctic coast, the Inupiaq village of Shishmaref, Alaska, is increasingly threatened by erosion, which is aggravated by the loss of sea ice and increased temperatures that lead to permafrost thaw. Credit: Shishmaref Alaska Erosion & Relocation Coalition

Why does it matter if the Arctic sea ice melts? We often hear about the global consequences: waning sea ice is expected to lead to even more climate warming. On a more immediate and local level, the loss of summer sea ice is already affecting the land and people near the Arctic Ocean. As the ice melts to reveal the open ocean underneath, fragile coastlines become vulnerable to bigger waves and storms. Continue reading