• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: 1996; Bockheim et al; 1998; Tarnocai; 2000; 60 % or more; Arctic; Bockheim; Global warming; permafrost; Thermokarst; Alaska
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.490.4454; http://www.globalcarbonproject.org/global/pdf/Bockheim_2008 Carbon in permafrost Alaska SSSAJ.pdf

transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Permission for printing and for reprinting the material contained herein has been obtained by the publisher PERMAFROST-AFFECTED SOILS (Gelisols) cover 11.2 × 106 km2 or 8.6 % of the world land area (Soil Survey Staff, 1999) and contain an estimated 393 Pg of C in the upper 100 cm. This reservoir constitutes 25 % of the global soil organic carbon (SOC) pool (Lal and Kimble, 2000). In the northern hemi-sphere, Gelisols cover 7.7 × 106 km2 and contain 268 Pg of SOC in the upper 100 cm of the soil profi le (Tarnocai et al., 2003). There is increasing concern that warming observed in the arctic will lead to an increase in the depth of the active layer, or the uppermost soil layer above permafrost that experiences thawing in summer and freezing in winter. Recently, Lawrence and Slater (2005) proposed that by 2100, only 10 % of the current 10.5 million km2 of permafrost is likely to remain within 3.4 m of the ground surface. Although these estimates may be extreme (Burn and Nelson, 2006), there is consensus that the upper permafrost will experience widespread thaw in this century (Anisimov and Nelson, 1997). Jorgenson et al. (2006) documented extensive permafrost degradation and thermokarst formation in arctic Alaska during the past 25 yr. Thawing of the near-surface perma-frost could enhance the release of CO2 and CH4 into the atmo-sphere from decomposition of SOC (Waelbroeck et al., 1997). Permafrost-affected soils constitute one of the three most vul-nerable sources of SOC to global warming (Intergovernmental