Climate change opens the gate to historic NSW floods

23.03.21 By

New South Wales is experiencing its worst flooding in decades, with torrential rain and widespread floods leading to thousands being evacuated and parts of the state being classified as areas of natural disaster. The rainfall, relentless across the east coast, has swollen the three rivers enclosing Sydney—the Nepean, Hawkesbury, and Georges—as well as the many others that flow through coastal NSW and southern QLD.

NSW Premier, Gladys Berejiklian has described the NSW floods as “not like anything we have seen for at least 50-60 years”. The NSW Mid North Coast, including the towns of Port Macquarie and Taree, has been particularly badly affected.

The deluge comes on the heels of other extreme weather events that have assailed NSW in recent years, including droughts, extreme heatwaves and, of course, the Black Summer bushfires. This pattern, of long droughts followed by unprecedented downpours, is what we expect from climate change. A warmer and wetter atmosphere can hold more water vapour—around 7 percent more for every degree of warming—and provide greater energy for weather systems. Globally, and in many parts of Australia, we are already experiencing more of our rainfall in the form of torrential downpours.

An infographic depicting the influence of climate change on flood risk.
The influence of climate change on flood risk.

Our report Hitting Home: The Compounding Costs of Climate Inaction describes this pattern:

“While climate change may mean only a modest increase in the overall amount of precipitation globally – limited by the moisture holding capacity of the atmosphere – it’s leading to a marked increase in the heaviest and most damaging storm events.”

“If the current trend continues, the frequency of today’s most intense precipitation events is likely to almost double with each degree of further warming.”

Describing those areas in potential need of evacuation, NSW Premier, Gladys Berejiklian, said “This is different to what we have experienced before. You may have had this five years ago or 10 years ago and your house was OK, but this is an event which far exceeds what has occurred in the last 50 or 60 years.”

These types of extreme weather events are set to become more—not less—intense and the billions of dollars in damage that are wreaked will continue to climb. Stronger action on climate change is fundamental to protecting communities and to preventing far far greater losses in future.

Urgent change must be demanded, and demanded now. Email your Federal MP today to lay down the necessity of reaching net zero emissions by 2035.