The story of the century is the warming of our planet. The evidence used in the story continues to build with a new satellite CyroSat- 2 (CS2), launched in April 2010 which gives the most accurate measurement of sea ice thickness to date. It differs in that it lets scientists estimate the volume of sea ice - a much more accurate indicator of the changes taking place in the Arctic. The report from CS2 is a stunner:
Arctic sea ice volume has declined by 36 per cent in the autumn and 9 per cent in the winter between 2003 and 2012, a UK-led team of scientists has discovered….Andy Lee Robinson has made a brilliant video of the findings data.
The findings confirm the continuing decline in Arctic sea-ice volume simulated by the Pan-Arctic Ice-Ocean Modelling & Assimilation System (PIOMAS), which estimates the volume of Arctic sea ice and had been checked using earlier submarine, mooring, and satellite observations until 2008.
The September 2012 record low in Arctic sea-ice extent was big news, but a missing piece of the puzzle was lurking below the ocean’s surface. What volume of ice floats on Arctic waters? And how does that compare to previous summers? These are difficult but important questions, because how much ice actually remains suggests how vulnerable the ice pack will be to more warming.From the report:
“Other people had argued that 75 to 80 percent ice volume loss was too aggressive,” said co-author Axel Schweiger, a polar scientist in the UW Applied Physics Laboratory. “What this new paper shows is that our ice loss estimates may have been too conservative, and that the recent decline is possibly more rapid.”
CryoSat-2 measures ice volume using a high-resolution synthetic aperture radar altimeter, which fires pulses of microwave energy down towards the ice. The energy bounces off both the top of sections of ice and the water in the cracks in between. The difference in height between these two surfaces let scientists calculate the volume of the ice cover.The prospect of continuing loss of sea ice projects an ice free Arctic in summer and more extreme weather events(pdf) such as flooding, droughts, heat and cold extremes. Of major concern is the release of methane bomb stored in the Arctic permafrost which could trigger massive runaway climate change.
The findings are the result of a huge international collaboration between teams from UCL, the European Space Agency, the Jet Propulsion Laboratory, the University of Washington, York University, Alfred Wegener Institute for Polar & Marine Research, Woods Hole Oceanographic Institution, Morgan State University and the University of Maryland.
The team confirmed CryoSat-2 estimates of ice volume using measurements from three independent sources - aircraft, moorings, and NASA's Operation IceBridge.