by Peter Sinclair, Climate Denial Crock of the Week, February 28, 2013
Dr Miller is lead scientist of NASA’s CARVE mission, (covered below in a Weather Channel spot, encouraging sign of better coverage for climate issues in that venue)..
CARVE stands for Carbon in Arctic Reservoirs Vulnerability Experiment, and it consists of an ongoing series of flights over permafrost regions in the remote Alaskan arctic, to measure at low altitude, and high resolution the offgassing of CO2 and methane from decaying permafrost.
When I spoke to him at the American Geophysical Union fall meeting in December, what was most striking were the even, calm, measured tones of his responses in discussing some of the most intense and alarming information imaginable about a critical climate feedback.
The story came together with last week’s publication of new data that helps zero in on exactly at what temperature regions of continuous permafrost will begin to break down.
Geoscientist Anton Vaks of the University of Oxford led an international team of experts—including the Arabica Caving Club in Irkutsk—in sampling the spindly cave growths known as stalagmites and stalactites across Siberia and down into the Gobi Desert of China. Taking samples of such speleothems from six caves, the researchers then reconstructed the last roughly 500,000 years of climate via the decay of radioactive particles in the stone. When the ground is frozen above a cave no water seeps into it, making such formations “relicts from warmer periods before permafrost formed,” the researchers wrote in a study published online in Science on 21 February 2013.
The details of the study reveal that conditions were warm enough even in Siberia for these mineral deposits to form roughly 400,000 years ago, when the global average temperature was 1.5 degrees Celsius higher than present. It also suggests that there was no permafrost in the Lena River region at that time, because enough water seeped into the northernmost cave to enable roughly eight centimeters of growth in the formations.