Rapid Net Carbon Loss From a Whole‐Ecosystem Warmed Peatland
Paul J. Hanson, Natalie A. Griffiths, Colleen M. Iversen, Richard J. Norby, Stephen D. Sebestyen, Jana R. Phillips, Jeffrey P. Chanton, Randall K. Kolka, Avni Malhotra, Keith C. Oleheiser, J. M. Warren, Xiaoying Shi, Xiaojuan Yang, Jiafu Mao, Daniel Ricciuto
Abstract
Abstract To evaluate boreal peatland C losses from warming, novel technologies were used to expose intact bog plots in northern Minnesota to a range of future temperatures (+0°C to +9°C) with and without elevated CO 2 (eCO 2 ). After 3 years, warming linearly increased net C loss at a rate of 31.3 g C·m −2 ·year −1 ·°C −1 . Increasing losses were associated with increased decomposition and corroborated by measures of declining peat elevation. Effects of eCO 2 were minor. Results indicate a range of C losses from boreal peatlands 4.5 to 18 times faster than historical rates of accumulation, with substantial emissions of CO 2 and CH 4 to the atmosphere. A model of peatland C cycle captured the temperature response dominated by peat decomposition under ambient CO 2 , but improvements will be needed to predict the lack of observable responses to elevated CO 2 concentrations thus far.