* Astronomy

Arctic Heats Up More than Other Places
Temperature change in the Arctic is happening at a greater rate than other places in the Northern Hemisphere, and this is expected to continue in the future.
As a result, glacier and ice-sheet melting, sea-ice retreat, coastal erosion and sea level rise can be expected to continue.
A new comprehensive scientific synthesis of past Arctic climates demonstrates for the first time the pervasive nature of Arctic climate amplification.
The U.S. Geological Survey led this new assessment, which is a synthesis of published science literature and authored by a team of climate scientists from academia and government. The U.S. Climate Change Science Program commissioned the report, which has contributions from 37 scientists from the United States, Germany, Canada, the United Kingdom and Denmark.

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Clue to break-up of ice shelves
US researchers have come up with a way to predict the rate at which ice shelves break apart into icebergs.
These sometimes spectacular occurrences, called calving events, are a key step in the process by which climate change drives sea level rise.
Computer models that simulate how ice sheets might behave in a warmer world do not describe the calving process in much detail, Science journal reports.

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"To predict the future of the ice sheet and to understand the past, we have to put the information into a computer. The models we have do not currently have any way to figure out where the big ice sheets end and where the ice calves off to form icebergs" - Richard B. Alley, the Evan Pugh professor of geosciences.

Ice sheets, such as those in Antarctica and Greenland, spread under their own weight and flow off land over the oceans. The Ross Ice Shelf in Antarctica floats for as much as 500 miles over the ocean before the edges begin to break and create icebergs. Other ice shelves only edge over the water for a mile or two.

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Crucial Arctic sea ice this summer shrank to its second lowest level on record, continuing an alarming trend, scientists said Tuesday.
The ice covered 1.74 million square miles on Friday, marking a low point for this summer, according to NASA and the National Snow and Ice Data Center in Boulder, Colo. Last summer, the sea ice covered only 1.59 million square miles, the lowest since record-keeping began in 1979.

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A scientific expedition this fall will map the unexplored Arctic seafloor where the U.S. and Canada may have sovereign rights over natural resources such as oil and gas and control over activities such as mining.
Both countries will use the resulting data to establish the outer limits of the continental shelf, according to the criteria set out in the Convention on the Law of the Sea. The extended continental shelf, the seafloor and subsoil beyond 200 nautical miles from shore that meet those criteria, is an area of great scientific interest and potential economic development.

The expedition will be collaboratively undertaken by the U.S. and Canada using two ships. The U.S. Geological Survey will lead data collection from September 6October 1 on the U.S. Coast Guard Cutter Healy to map the Arctic seafloor. The Geological Survey of Canada, Natural Resources Canada will follow Healy on the Canadian Coast Guard ship Louis S. St. Laurent (Louis) and study the geology of the sub-seafloor.

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