Corals record long-term Leeuwin current variability including Ningaloo Niño/Niña since 1795

Area of Science:

• Oceanography
• Climate Science
• Paleoclimatology

Background:

• The Leeuwin Current (LC) variability reflects Indo-Pacific climate shifts.
• Extreme events, such as Ningaloo Niño, involve strengthened LC, high sea levels, and warm sea surface temperatures (SSTs).
• Understanding these events is limited by a lack of long-term data.

Observation:

• Coral SST records and El Niño-Southern Oscillation reconstructions were used to hindcast LC strength and SST from 1795 to 2010.
• Analysis covered 215 years of interannual and decadal variations in LC strength and SST.

Findings:

• Interannual and decadal variability in LC strength and SST were evident over the past 215 years.
• The most extreme sea level and SST anomalies occurred after 1980.
• Recent extreme events were unprecedented in severity.

Implications:

• Accelerated global ocean warming and sea-level rise likely contribute to the severity of recent extreme LC events.
• These findings highlight the sensitivity of the southeastern Indian Ocean to climate forcing.
• The study underscores the need for continued monitoring of the LC and its associated climate phenomena.