Is Arctic Permafrost the "Sleeping Giant" of Climate Change?   
       
   June 24, 2013: Flying low and slow above the pristine terrain of Alaska's   
   North Slope research scientist Charles Miller of NASA's Jet Propulsion   
   Laboratory surveys the white expanse of tundra and permafrost below. On the   
   horizon, a long, dark line appears. His plane draws nearer, and the mysterious   
   object reveals itself to be a massive herd of migrating caribou, stretching   
   for miles.   
       
   It's a sight Miller won't soon forget.   
       
   "Seeing those caribou marching single-file across the tundra puts what we're   
   doing here in the Arctic into perspective," says Miller, who is on five-year   
   mission named "CARVE" to study how climate change is affecting the Arctic's   
   carbon cycle.   
       
   http://www.youtube.com/watch?v=hZSM8GcmJKg   
       
   A new ScienceCast video peeks beneath the topsoil to inspect the carbon stores   
   of Arctic permafrost. Play it   
       
   CARVE is short for the "Carbon in Arctic Reservoirs Vulnerability   
   Experiment."  Now in its third year, the airborne campaign is testing the   
   hypothesis that Arctic carbon reservoirs are vulnerable to warming, while   
   delivering the first source-maps of greenhouse gases carbon dioxide and   
   methane. About two dozen scientists from 12 institutions are participating.   
       
   "The Arctic is critical to understanding global climate," says Miller.   
   "Climate change is already happening in the Arctic, faster than its ecosystems   
   can adapt. Looking at the Arctic is like looking at the canary in the coal   
   mine for the entire Earth system."   
       
   Over hundreds of millennia, Arctic permafrost soils have accumulated vast   
   stores of organic carbon - an estimated 1,400 to 1,850 billion metric tons of   
   it.  That's about half of all the estimated organic carbon stored in Earth's   
   soils. In comparison, about 350 billion metric tons of carbon have been   
   emitted from all fossil-fuel combustion and human activities since 1850. Most   
   of the Arctic's sequestered carbon is located in thaw-vulnerable topsoils   
   within 3 meters of the surface.   
       
   But, as scientists are learning, permafrost - and its stored carbon - may not   
   be as permanent as its name implies. And that has them concerned.   
       
   "Permafrost soils are warming even faster than Arctic air temperatures - as   
   much as 1.5 to 2.5 degrees Celsius in just the past 30 years," says Miller.   
   "As heat from Earth's surface penetrates into permafrost, it threatens to   
   mobilize these organic carbon reservoirs and release them into the atmosphere   
   as carbon dioxide and methane, upsetting the Arctic's carbon balance and   
   greatly exacerbating global warming."   
       
   CARVE campaign flights are conducted aboard a specially instrumented NASA C-23   
   Sherpa aircraft from NASA's Wallops Flight Facility on Wallops Island in   
   Virginia. The C-23 won't win any beauty contests - its pilots refer to it as   
   "a UPS truck with a bad nose job." Inside, it's extremely noisy - the pilots   
   and crew wear noise-cancelling headphones to communicate. "When you take the   
   headphones off, it's like being at a NASCAR race," Miller quipped.   
       
   But what the C-23 lacks in beauty and quiet, it makes up for in reliability   
   and its ability to fly "down in the mud."  Most of the time, it flies about   
   150 meters above ground level, with periodic ascents to higher altitudes to   
   collect background data. Onboard the plane, sophisticated instruments sniff   
   the atmosphere for greenhouse gases.  "[We] need to fly very close to the   
   surface in the Arctic to capture the interesting exchanges of carbon taking   
   place between Earth's surface and atmosphere," Miller says.   
       
   The CARVE team flew test flights in 2011 and science flights in 2012. So far   
   in 2013 they have completed three monthly campaigns--in April, May and   
   June--with four more to go.   
       
   From a base in Fairbanks, Alaska, the C-23 flies up to eight hours a day to   
   sites on Alaska's North Slope, interior and Yukon River Valley over tundra,   
   permafrost, boreal forests, peatlands and wetlands.   
       
   Soaring over the Arctic terrain, Miller has seen many things he won't forget.    
   The permafrost data may prove unforgettable, too.   
       
   Credits:   
       
   Production editor: Dr. Tony Phillips | Credit: Science@NASA   
       
   More information:   
       
   Carbon in Arctic Reservoirs Vulnerability Experiment home page   
       
       
   Regards,   
       
   Roger   
      
   --- D'Bridge 3.94   
    * Origin: NCS BBS - Houma, LoUiSiAna (1:3828/7)