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Satellites check in on the North Pole

NSIDC

This visualization shows Saturday's extent of Arctic sea ice, as charted by the National Snow and Ice Data Center. The readings have been overlaid on NASA imagery of the Northern Hemisphere. The orange line indicates the median extent of sea ice on the same calendar date for the 1979-2000 time period.



If Santa Claus is getting the feeling that someone's looking over his shoulder as he rushes to make his Christmas deadline, he's not wrong: A succession of satellites is monitoring his North Pole workshop and the rest of the Arctic on a daily basis. Based on the satellite readings, the long-term outlook is worrisome, for Santa and the rest of us as well.


This image shows the extent of Arctic sea ice, based on the latest microwave data from the Pentagon's DMSP-F17 satellite. Those readings are compared against the median extent for the same date over the 1979-2000 time frame. That median extent is indicated on the photo by the orange lines.

Earlier this month, the National Oceanic and Atmospheric Administration said in its annual "Arctic Report Card" that glaciers and sea ice retreated at a record rate this year, and that sea level rise has accelerated in the region. What's more, those changes are affecting ecosystems in the far north — spurring marine phytoplankton growth while putting extra pressure on land species such as lemmings and the Arctic fox.

There's also a spillover effect on ecosystems farther south. "What happens in the Arctic doesn't always stay in the Arctic," NOAA Administrator Jane Lubchenco said. "We're seeing Arctic changes in the ocean and the atmosphere that affect weather patterns elsewhere."

Keep tabs on those changes by checking in with NBC News' environmental coverage. For more visualizations of Arctic as well as Antarctic ice data, check out this reference page at the "Watts Up With That" blog. You can also scan NASA's report about this summer's retreat of the Arctic's ice cover. And for something completely different, here are 10 things you may not have known about the North Pole.

Today's visualization of the North Pole's ice is the latest offering from the Cosmic Log Space Advent Calendar, which features daily images of Earth from space through Christmas. Try these other visual goodies from the calendar:

Correction for 9:15 p.m. ET: I originally referred to the median extent of Arctic sea ice, but changed that reference to use "average" instead — which was an ill-advised move. Generally speaking, an "average" value refers to the mean, which can be quite different from the median. Here's an explanation from Purplemath that lays out the difference. Thanks to commenters for pointing out the distinction. (I also fixed a typo referring to "sea level rice.")


Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other science and space news coverage, sign up for the Tech & Science newsletter, delivered via email. You can also check out "The Case for Pluto," my book about dwarf planets and the search for new worlds.