Chapter 5 Climate Research

IGBP Activities

The International Geosphere-Biosphere Programme (IGBP) was established by ICSU in 1986 to promote studies of the interacting physical, chemical and biological processes affecting global change. The structure of IGBP is currently being modified following a sustained period of synthesis and analysis.

The activities of IGBP and WCRP are coordinated in Australia through the National Committee for Earth System Science (NCESS). Some of the highlights of current Australian research in IGBP relevant to climate science are summarised below.

• Adelaide University is contributing to the Past Global Changes (PAGES) project, called LIMPACS, on sedimentbased approaches to identifying climate and human impacts on the health of lakes across the world.
• ANSTO is coordinating projects to quantify the chronology and extent of glacial cycles in the southern hemisphere using cosmological long-lived radioisotopes and surface exposure dating. One objective is to compare the phasing and magnitude of glacial cycles in the southern hemisphere with those in the northern hemisphere.
• In collaboration with Sydney University, ANSTO is measuring regional variations in atmospheric carbon-14 in tree rings from Southeast Asia and Australia to infer changes in the atmospheric circulation in past centuries.

  
  
  Dr Henk Heijnis from ANSTO sampling a sediment core extracted from the mouth of the Nattai River. This core was used to investigate fire and sediment history of the Burragorang catchment in New South Wales in relation to past climate change.

• As a contribution to the PAGES Human Impacts on Terrestrial Ecosystems (HITE) project, ANSTO is leading a project, involving several Australian universities and government organisations, to investigate the impacts of climate variability and human activity on natural systems over the last 200 years. The research involves the collection and analysis of sediment cores from lakes.
• Analysis of atmospheric composition in the CSIRO GASLAB shows continuing increases in the concentrations of carbon dioxide and methane (Figure 5.14). The rate of increase of carbon dioxide had maxima in 1994-95 and 1997-98 which are found to be associated with biomass burning rather than variations in the terrestrial biosphere exchange. The reason for the stablisation of methane in the atmosphere over the past three years remains uncertain.

  
  
  Figure 5.14. Atmospheric carbon dioxide concentration, measured at the Cape Grim Baseline Air Pollution Station in north-western Tasmania. (Courtesy CSIRO)

• In collaboration with AAD, Antarctic CRC, Melbourne University and groups in USA and UK, CSIRO is analysing Antarctic ice cores to extend the highresolution record of atmospheric composition back to 11,000 years BP. By analysing air in the Antarctic firn, changes in composition over the last fifty years have been followed to show the growth of halocarbons, carbon dioxide and rare isotopic tracers such as carbon-14 in methane; the latter involves collaboration with ANSTO and New Zealand.
• A new method has been developed by CMR to estimate the accumulation of carbon dioxide in the ocean from CFCderived water ages.
• Research in CMR has shown that the decline in dissolved oxygen in the ocean could be used to detect climate change.
• Model simulations in CMR suggest that, while global deep-ocean anoxia is unlikely under continuing global warming, there is a potential for regional anoxia on time scales of hundreds of years.
• Measurements and modelling in CMR suggest that the parameterisation of biological production in global models may need to be revised to recognise that the assumption of constant stoichiometric linking of carbon, phosphate and nitrate uptake may be false.

  
  
  This ship-borne measuring instrument obtains details of dissolved oxygen to a depth of 6000 metres. (Courtesy CSIRO)

• Research on radon (Rn²²²) is continuing at ANSTO based on observations from Cape Grim and Mauna Loa. Revised datasets have been developed, and a new method for estimating the regional oceanic flux of radon has been formulated.
• ANSTO is participating in the International Global Atmospheric Chemistry (IGAC) Aerosol Characterisation Experiment campaign in East Asia (ACE-Asia) through measurements of fine particles and radon at several sites. The data are being used on both regional and global transport model studies.

  
  
  CSIRO has installed Australia’s first long-term greenhouse gas flux station, on a 70-metre mast in a tall eucalypt forest near Tumbarumba in southeast New South Wales. (Courtesy CSIRO)

• CSIRO continues to measure and analyse a range of stable and reactive gases at the Cape Grim BAPS. The program included participation in the international SAFARI experiment, in which the transport of smoke from Africa to Australia was identified.
• Infrared spectroscopy is being used at Wollongong University to measure the flux and isotopic signature of nitrous oxide. From in situ measurements and laboratory studies, estimates of the destruction of nitrous oxide in the stratosphere have been made in collaboration with USA research groups.
• As a contribution to the international FluxNet program, CSIRO is studying the uptake of carbon by Australia's unique ecosystems under current and climate change conditions. Measurements are being taken at two different sites (one in the northern tropics and the other in the southeast temperate zone), and the annual water and carbon cycles are found to be profoundly different. These sites are part of OzFlux, a network of seven monitoring stations across Australia and New Zealand that commenced in 1999.