How Climate Change Fuels Coastal Floods and Inland Droughts: Understanding the Connection

Australia has been experiencing some unusual weather lately. From Queensland down to the South Coast of New South Wales, rainfall has surged significantly. This increase began with Ex-Tropical Cyclone Alfred in March. A study by ClimaMeter found that climate change has made storms not only wetter but also slower.

As the planet warms, climate scientists predict fewer cyclones in Australia. However, they also warn that these storms are moving south and bringing more rain when they do occur. Just this week, the Mid North Coast of NSW suffered severe flooding. For instance, Taree saw its record rainfall—about 400 millimeters in just two days, which is about a third of what it usually gets in a year.

These sudden weather changes can also lead to coastal erosion. An East Coast Low impacted beaches on the Central Coast, with some still stripped of sand months later. According to environmental experts, events like this can be linked to a positive Southern Annular Mode (SAM), which contributes to extreme weather patterns.

Climate change is affecting how much moisture the atmosphere can hold. For every degree of warming, it can carry about 7% more humidity. Over recent decades, the global atmosphere has indeed seen this increase alongside rising temperatures.

Scientia Professor Matthew England from the University of NSW notes that warmer oceans make rain more intense. “Onshore winds pick up moisture from these warmer waters, which means more atmospheric humidity,” he says. Recent data indicates that sea temperatures in the Tasman Sea have been above average, intensifying coastal rainfall.

Interestingly, while coastal areas see heavy rainfall, inland regions are abnormally dry. McDowell points out that parts of Victoria, NSW, South Australia, and Tasmania recorded their lowest rainfall on record in March and April. “The weather patterns are shifting, possibly due to climate change,” he adds.

Such trends have also been linked to changes in atmospheric pressure. As greenhouse gas levels rise and the ozone layer starts to recover, the SAM is expected to shift, leading to more extreme weather events.

Dr. Chiara Holgate from the ARC Centre of Excellence for Weather of the 21st Century cautions that while we can’t pinpoint climate change as the sole cause of specific droughts or floods, regions currently facing drought may see these events becoming more common due to ongoing climate shifts.

Looking forward to winter, the forecast suggests that Australia’s east coast and inland areas might see more rainfall than usual, especially in August. The Bureau of Meteorology expects a negative Indian Ocean Dipole, which typically brings more rain. However, as McDowell notes, long-range predictions come with uncertainties that should be considered carefully.

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