As Queensland copes with the impacts of the 2010-2011 wet season, research undertaken by the Australian Institute of Marine Science shows the frequency of extreme rainfall events has increased since the late 19th century.

In a paper recently accepted in the prestigious scientific journal, Paleoceanography, Dr Janice Lough, an expert in climate change science, explains how her latest research on the subject supports predictions that tropical rainfall will become more variable in a warming world.

Dr Lough said: “At AIMS we have Australia’s most comprehensive library of coral cores, from long-lived Porites corals on the Great Barrier Reef.

“The cores have annual bands, similar to tree rings. They give us a record of the ocean environment throughout the coral’s life, dating back several centuries, before weather and climate were monitored with rain gauges and thermometers.”

One record in the coral (first discovered by AIMS’ scientists in the 1980s) are bright luminescent lines which reflect the occurrence and intensity of river flood events affecting inshore corals during the summer wet season. The river and rainfall histories in these lines, evident when coral slices are placed under an ultra-violet light, can now be measured using a custom-built luminometer at AIMS.

Combining these records from several long coral cores from the Great Barrier Reef has allowed AIMS to reconstruct northeast Queensland summer rainfall back to the late 17th century – providing over 300 years of records to examine past climate variability and change.

“This new reconstruction tells us that the 1973-1974 summer wet season was the wettest in at least the past three centuries,” Dr Lough said.

“Queensland rainfall is characterised by very high variability. Extreme wet and extreme dry events have always occurred. But now we have evidence that those events are occurring more frequently than in earlier centuries, often with devastating effects.”

Dr Lough said the internationally peer-reviewed research would contribute to the body of knowledge currently being taken into consideration by town planners, managers, developers, emergency services and policy makers.

“The fact that extreme wet and extreme dry weather will happen more often and can potentially impact on thousands of people and millions of dollars worth of property, is something that the community will have to consider,” she said.

Dr Lough said AIMS would submit the research to the State Government’s judicial inquiry in to the recent floods in SE Queensland.