Coasts and oceans

Coasts and oceans

Prior to the ACCSP Australia did not carry out any research on the role of oceans in the climate. There were no consistent observation programmes in place, and there were no measurements south of Australia with sufficient resolution to determine how much water, heat and salt are carried from the Indian Ocean to the Pacific by the Antarctic Circumpolar Current.

ACCSP researchers made substantial progress in understanding the behaviour of the oceans surrounding our continent and their role in the climate system. They have also been leaders in international efforts to rigorously assess the extent to which sea level will change as the Earth warms, and in monitoring and modelling ocean acidification.

The ACCSP supported Australia’s involvement in the Argo programme, a major international collaboration to observe the world’s oceans using a network of nearly 4000 robotic profiling floats. (The first 10 floats launched in 1999 were Australian.) The ACCSP also supported Australia’s participation in the Global Ocean Ship-Based Hydrographic Investigations Program (GO-SHIP), a coordinated global program to collect ship-based observations. Data collected in this program is used to benchmark data that is collected autonomously, such as from the Argo program.

ACCSP science highlights

  • Directly measuring the transfer of anthropogenic carbon dioxide into the southern hemisphere oceans for the first time.
  • Determining the strength of the Southern Ocean overturning circulation (the circulation of seawater driven by changes in the heat and water density) and highlighted the sensitivity of this circulation to climate change.
  • Demonstrating how the Southern Ocean links the shallow and deep limbs of the ocean ‘conveyor belt’, and so plays a key role in the heat engine that influences global climate patterns
  • Showing that the Adelie Land coast of Antarctica produces about 25 per cent of the global volume of the dense Antarctic Bottom Water that oxygenates the deep ocean
  • Providing new insights into the complex physical, biological and chemical interactions that determine the biological productivity and carbon dioxide absorbed by the Southern Ocean.
  • Detecting decreasing oxygen concentrations in the Southern Ocean and changes in seawater properties that suggest precipitation has increased at high southern latitudes.
  • Demonstrating that continuing global mean sea level rise and determined that the larger rate of sea-level rise since 1993 is largely a result of changes in natural forcing of climate and ongoing anthropogenic greenhouse gas emissions.
  • Developing regional projections of sea-level rise from 1996 to 2100 for the Australian coastline, and determining sea-level allowances, the height by which coastal property must be raised so that the risk of coastal inundation does not increase.
  • Monitoring the rate of change of ocean acidification in the ocean around Australia.

More information on these and other science highlights is available in the ACCSP Annual Reports.