Multi-decadal climate variability, New South Wales, Australia

Area of Science:

• Hydrology
• Climate Science
• Environmental Risk Assessment

Background:

• Traditional hydrological risk assessment assumes static climate conditions.
• Recent studies reveal persistent multi-decadal climate state epochs in New South Wales (NSW), Australia.
• Multi-decadal variability in El Niño/Southern Oscillation (ENSO) impacts on climate extremes is also documented.

Purpose of the Study:

• To present examples of multi-decadal variability in flood and drought risk.
• To explore the causal mechanisms behind observed climate variability.
• To argue for the utility of climate variability insights in hydrological forecasting, design, and climate model testing.

Main Methods:

• Analysis of historical hydro-climatological data from NSW.
• Examination of multi-decadal climate variability patterns.
• Exploration of causal mechanisms for climate variability.

Main Results:

• Demonstration of multi-decadal variability in flood and drought risk in NSW.
• Identification of causal mechanisms driving observed climate variability.
• Evidence supporting the link between climate variability and extreme hydrological events.

Conclusions:

• Insights into climate variability offer improved seasonal hydrological risk forecasting.
• A new framework for hydrological design is strongly supported by climate variability understanding.
• Natural climate variability provides a valuable case study for testing General Circulation Models.