Tag Archives: climate

Summer predictions for Arctic sea ice

Posted on by
graph of estimates from the SEARCH sea ice outlook

Last week, an international group of researchers released their best estimates for Arctic sea ice extent over the summer melt season. The scientists are compiling their estimates so that they can better predict changes in Arctic sea ice. Credit: SEARCH Sea Ice Outlook

Average Arctic sea ice extent this May was the third lowest in the satellite record. Does that mean that ice extent will reach a new record low this summer? Or will it recover somewhat over recent years?

Last week sea ice scientists from around the world shared their best answers to those questions, in the June report of the Sea Ice Outlook. For the report, the researchers used a variety of methods to predict how sea ice will behave this summer, such as statistical methods or computer models. Continue reading →

When will the Arctic lose its sea ice?

Posted on by
sea ice and icebergs

Scientists expect the Arctic to lose most of its summer ice cover by the end of this century, and are working to determine when this might happen. Here, open water in Fram Strait, in the Canadian Arctic, is interspersed with chunks of sea ice. Credit: Angelika Renner

If you have been following the topic of Arctic sea ice, you have probably seen a few headlines warning that the Arctic is about to lose its summer ice cover. Although scientists agree that Arctic sea ice is declining, they have published several different estimates of when the last of the sea ice will melt in summer, leaving more ocean surface open to absorb heat and add to global warming. What is behind all these different predictions? Continue reading →

Arctic sea ice and U.S. weather

Posted on by

People sometimes wonder if the weather they are experiencing locally, such as the heavy snow that fell in February 2011 over the Northeastern U.S., is connected to decreasing Arctic sea ice. Scientists are exploring a possible connection. Credit: NASA Earth Observatory.

Over the 2010 to 2011 winter, news stories suggested a potential connection between a warming climate, low Arctic sea ice extent, and unusually cold weather this winter in the U.S. and Europe. What do scientists know about how sea ice affects the weather?

Scientists have been exploring a possible link, but the question is far from settled. It makes sense that changing sea ice conditions could affect weather in the Arctic and other parts of the world. During the colder months, sea ice insulates the relatively warm ocean from the colder atmosphere. As sea ice declines, more heat can escape to the atmosphere in the fall and winter, affecting wind patterns, temperature, and precipitation. Continue reading →

Is dirty air adding to climate change?

Posted on by

Bright white sea ice reflects light and keeps the Arctic cool. Soot darkens the ice surface and can speed melt. Credit: Andy Mahoney, NSIDC

Soot: it’s bad for human health, and bad for the health of the Earth, too. According to new research, it’s speeding up the loss of sea ice in the Arctic—ice that is vital to keeping the Earth cool. The Arctic’s summer covering of sea ice fell 30 percent over the last thirty years, and researchers expect that downward trend to continue. Scientists say that CO2 emissions account for much of the ice loss. But soot plays a role as well, and it might be easier to control.

How much is soot contributing to the problem? More than we thought, according to Mark Jacobson at Stanford University. It works like this: as sea ice melts, larger areas of open water absorb heat and add to ice melt. Soot falls on sea ice and amplifies that effect by making the ice surface darker and less reflective. “Black carbon over snow absorbs not only sunlight coming down but also sunlight reflected off of snow and ice coming back up,” Jacobson said. His study, published last summer in Journal of Geophysical Research, showed that soot particles are second only to greenhouse gases in the decline of Arctic sea ice. Continue reading →