ABSTRACT: The terrestrial carbon (C) sink has been large in recent decades, but its size and location remain uncertain. Using forest inventory data and long-term ecosystem C studies, we estimated a total forest sink of 2.4 Â± 0.4 Pg C yrâ€“1 globally for 1990â€“2007. We also estimated a source of 1.3 Â± 0.7 Pg C yrâ€“1 from tropical land-use change, consisting of a gross tropical deforestation emission of 2.9 Â± 0.5 Pg C yrâ€“1 partially compensated by a C sink in tropical forest regrowth of 1.6 Â± 0.5 Pg C yrâ€“1. Together, the fluxes comprise a net global forest sink of 1.1 Â± 0.8 Pg C yrâ€“1, with tropical estimates having the largest uncertainties. This forest sink is equivalent in magnitude to the terrestrial sink deduced from fossil fuel emissions and constraints of ocean and atmospheric sinks.
Science. 01/2011; 333:988-993.