A Climate Services Perspective on Two Significant Climate and Weather Events in Australia

This century, Australia has experienced a large increase in the frequency and magnitude of extreme weather events related to changes in mean surface temperature over land and sea surface temperatures in surrounding oceans. A number of these events have been studied in an attribution framework as summarised in the BAMS Special Reports on extreme events.  We describe two extreme events in Australia during 2016 that involve a mix of climate and weather drivers, and attracted both local and international attention. Due to a by-chance confluence of extremes in a number of variables, the events provide a window into a future where such conditions will occur more commonly as human induced climate change increases into the future.

Stretching for 2300 km, the Great Barrier Reef is home to thousands of species of marine creatures and is a major tourist destination, attracting 14 million recreational visitors each year. During northern Australia’s wet season in 2015/16, sea surface temperatures (SSTs) along the Great Barrier Reef were warmest on record by some margin. During the late summer and austral autumn, mass coral bleaching occurred in much of the 344,400 square kilometres of the Great Barrier Reef Marine Park. Overall, coral mortality was 22 per cent, with the vast majority of coral loss occurring in the northern third of the Reef.

In early June, an intense low pressure system (categorized locally as an East Coast Low) affected the eastern coast of Australia. The event from 4-7 June was remarkable for the large extent of heavy rainfall and flooding that extended from New Caledonia to Tasmania in far southern Australia. Sea surface temperatures along most of Australia’s east coast were at their warmest on record in the lead-up to the event, providing record amounts of moisture to the system. With the storm surge coinciding with a high astronomical tide, record wave heights were observed resulting in significant coastal erosion and iconic photographs of swimming pools and houses falling into the sea.

Such events provide a glimpse into the future, reinforcing the message from scientists about the likely future impacts of climate change.