Session: Benchmarking & cross-cutting Group 1 (Isotope modelling, COMPARE)
Author: Zicheng Yu / ziy2@lehigh.edu / Lehigh University
Co-author: PAGES C-PEATP Working Group, ;

Abstract:
Peats represent a large, and often active, carbon (C) pool in the land-atmosphere system. At present, these C-rich deposits contain about 600 Pg C that has accumulated mostly since the Last Glacial Maximum -- an amount similar to the total C stocks in all living biomass or in the atmosphere. Northern (boreal and sub-Arctic) peatlands contain >90% of this C pool, followed by tropical and southern peatlands. The large size of the peat C pool and its concentration in a number of regions sensitive to climate change and human activities have promoted a heightened interest and increased research in peat C dynamics. We know that peatlands played a major role in the global carbon cycle during the Holocene as recognized by the latest IPCC report. Also, we have learned much about their distributions, histories and controls as a result of site-level, data synthesis, and modeling studies. However, we still lack understanding of climate sensitivity of these C-rich ecosystems, especially at continental and regional scales, which limits our ability to project their future trajectories. Furthermore, we have little idea about the C pool size and dynamics of peat deposits further back in time, such as during the previous interglacials, the Pliocene and beyond. The PAGES’s C-PEAT Working Group aims to facilitate the interactions of international peat C researchers working on peat of all ages, including ecosystem and global modeling scientists. We continue to focus our effort on the Holocene because of the abundance of information available from northern, tropical and southern peatlands, but we also start our exploration of pre-Holocene peats using what we have learned from the studies of Holocene-age peatlands. Understanding the climate sensitivity and contribution of peat deposits to the global carbon cycle in the past, particularly their impact on atmospheric CO2 and CH4 concentrations, is critical to projecting their change in the future. Paleo data are essential not only for documenting carbon sequestration histories but also for evaluating and validating global climate-carbon cycle models. To that end, various available and ongoing peat C synthesis products will be useful for benchmarking PMIP4 simulations.