G. Pearman’s emphasis on global representativeness during establishment of Australian CO 2 monitoring underpins this work. Data used in this report are routinely submitted to the World Data Centre for Greenhouse Gases and CDIAC international databases (but in formats that preclude the data selection and uncertainty propagation used in this paper). More comprehensive and recent data, including LoFlo data, are available to researchers by contacting paul.krummel@csiro.au. CSIRO GASLAB staff and the Australian Bureau of Meteorology/Cape Grim Baseline Air Pollution Station continue to provide excellence in the operation of developmental equipment and in collection and processing of samples and data. Collection of samples at other sites is carried out with assistance from NOAA (USA), Environment Canada, Australian Antarctic Division and Australian Bureau of Meteorology. R.J.F, M.v.d.S., P.B.K., R.L.L., L.P.S and C.E.A. have been partly financially supported by the Bureau of Meteorology through the Cape Grim programme. R.J.A. was sponsored by US Department of Energy, Office of Science, Biological and Environmental Research (BER) programmes performed at Oak Ridge National Laboratory (ORNL) under US Department of Energy contract DE-AC05-00OR22725. CSIRO co-authors have been partly financially supported by the ACCSP (Australian Climate Change Science Program) through the Department of Climate Change and Energy Efficiency. A.R.S. is partially supported by an OCE (Office of Chief Executive) post-doctoral award. CCAM model simulations were undertaken on the NCI National Facility in Canberra, Australia, which is supported by the Australian Commonwealth Government. Valuable comments have been received from Y-P. Wang, P. Canadell, P. Rayner and A. Lenton.