Climate Change and the Ocean

ACE-CRC ScienceFrom Antarctica to

Australia

Key questions

How does the Southern Ocean influence global and regional climate?

Is the Southern Ocean changing? Can we tell if it is climate change or a natural cycle?

Will changes in Antarctica and the Southern Ocean influence Australian climate?

Connecting ocean basins

Rintoul et al., 2001

Overturning circulation

Rintoul, 2001

Ocean uptake of CO2

Sabine et al., 2004

Ocean heat storage More than 90% of “global warming” is in

the ocean.

Levitus et al., 2004

Ocean heat storage

Most of the change in ocean heat content is in the southern oceans.

Levitus et al., 2004

“I think we’ve hit a critical desalinization point!”

Dennis Quaid, renowned climatologist

Sensitivity to climate change

Hirst et al.,

ACE observations

Antarctic Bottom Water

Rapid changes in the deep SO In 10 years, the

deep layers of the entire basin have become fresher and less dense.

Causes of fresher shelf water

Increased glacial ice melt, due to warmer ocean

More precipitation Less sea ice

formation Change in winds

(eg southern annular mode)

Davis et al., Vaughan; Science, 2005

Link to Australian climate?

Southern Ocean winds further north?

Southern Ocean winds further

south?

Summary

The Southern Ocean has a significant influence on global and regional climate.

Growing evidence for change in Antarctica and the Southern Ocean – but still too soon to tell if it is a natural cycle or due to human activities.

Australia will not be immune to changes in Antarctica and the Southern Ocean.

Understanding SO change will enhance our ability to adapt to future change.