The Carbon Cycle: Global and Australian Perspectives

Australian Institute of Physics (AIP, ACT Branch) and The Australian Meteorological and Oceanographic Society (AMOS) September Branch Meeting
Date: Tuesday, 10 September 2002
Time: 18.00 (refreshments from 17.30)
Venue: Link Building Seminar Room, RSPhysSE

Speaker: Dr Michael Raupach, CSIRO Land and Water

Over the last five years there have been dramatic advances in understanding of the main fluxes in the global carbon cycle. A full, globally integrated carbon budget has been developed, showing that of the 6.5 GtC per year that enters the atmosphere from fossil fuel burning, only about half remains in the atmosphere, with the other half being taken up in a combination of oceanic and terrestrial sinks. Many properties of these sinks are now emerging, for instance: (1) the total terrestrial sink probably exceeds the ocean sink, but the net terrestrial sink (total sink less emissions due to land use change) is less than the ocean sink; (2) the terrestrial sink accounts for most of the interannual variability in accumulation of CO2 in the atmosphere; (3) the net terrestrial sink appears to have increased over last 20 years, but is likely to saturate and then decline over a time frame of 50-100 years.

The current state of knowledge will be reviewed, with emphasis on (1) key lines of observational evidence; and (2) modelling approaches, and how they are being combined with observations in several ways.

Finally, the Australian perspective will be examined by outlining recent work aimed at estimating changes since European colonisation in carbon and related (water, nutrient) cycles on the Australian continent.