C-LEAK · Rivers as leak in the terrestrial C sink

Rivers as leak in the terrestrial C sink

Inland waters play an important role in the global carbon (C) cycle, both as land-ocean transport routes and as ecosystems where large amounts of organic C derived from terrestrial ecosystems are processed, generating substantial net-emissions of CO2 to the atmosphere, or buried and sequestered in aquatic sediments. Researchers from the field of aquatic biogeochemistry have been pointing out the substantial role the inland water plays for the terrestrial C and greenhouse gas budget for over a decade (Cole et al., 2007; Lauerwald et al., 2015; Raymond et al., 2013; Tranvik et al., 2009). It was however only in their latest report (Ciais et al., 2013) that the IPCC acknowledged the role of inland waters for the global C cycle, and Earth System models (ESMs) used to project the terrestrial sink for anthropogenic CO2 emissions still ignore the role of inland waters as a lateral link between land and ocean and as a greenhouse gas source to the atmosphere. There is evidence that anthropogenic actions increase C exports from the terrestrial systems through inland waters, e.g. by increasing erosion from agricultural soils, sewage injections or indirectly by thawing permafrost (Regnier et al., 2013). Thus, ignoring the leakage of C from terrestrial ecosystems through the inland water network potentially leads to an overestimation of the terrestrial land C sink and, consequently, to the underestimation of atmospheric CO2 concentrations and air temperatures in future projections (Ciais et al., in revision for Nature). Representing inland water C fluxes in an ESM framework would improve the assessment of the anthropogenic perturbation of the global C cycle and climate projections. The objective of this research project was to overcome the limitations of recent ESMs and global C budget estimates by implementing the cycling of terrestrial C through inland waters into an integrated modelling framework. This allows simulation of the evolution of inland water C fluxes under climate change, anthropogenic CO2 emissions, land use change, land use related soil erosion, and river damming, and their implications for the terrestrial C budgets.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз