An alternative explanation to the size and location of the missing sink Robert Andres 1 Skee Houghton 2 1 Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN USA 2 Woods Hole Research Center, 149 Woods Hole Road, Falmouth, MA USA NACP, New Orleans 1/13

Talk Motivations 1. Uncertainty evaluation of FFCO 2 time series is an ongoing process. 2. Uncertainty realization effects our collective knowledge of the global carbon cycle. NACP, New Orleans 2/13

Uncertainty Analysis and FFCO 2 Time Series Classic Approach: independent measurements of variable Reality: insufficient number of independent measurements at spatial and temporal scales of interest to the statistical basis of FFCO 2 inventories Approach: assess pieces that can be analyzed Several Methods: By mass: spatial scales – global, national, sub-national temporal scales – annual, monthly, … By isotope: stable carbon, radiocarbon available data include combinations of spatial and temporal factors NACP, New Orleans 3/13

Methodology NACP, New Orleans 4/13

Methodology NACP, New Orleans 5/13

Methodology NACP, New Orleans 6/13

Results Mass weighted average = 9.7% Year weighted average = 9.3% NACP, New Orleans 7/13

Results NACP, New Orleans 8/13

Implications: Uncertainty Propagation Example terrestrial biosphere = fossil fuel emissions + land use emissions – oceanic uptake – atmospheric reservoir increase NACP, New Orleans 9/13

Implications: GCP Data NACP, New Orleans 10/13

Implications: GCP Data – 2 σ FFCO 2 NACP, New Orleans 11/13

Implications: GCP Data + 2 σ FFCO 2 NACP, New Orleans 12/13

Conclusions 1. Uncertainty estimates associated with the fossil fuel CO 2 term continue to be examined. 2. Uncertainty propagation has implications for understanding the rest of the global carbon cycle components, not only in their magnitude but sometimes as to whether they are a source or sink. 3. Size: may partially be hidden in the error terms of other components Location: may not be on land NACP, New Orleans 13/13