Climate Council Statement On NSW Floods: More Destructive Due To Climate Change

The Mid-North Coast of NSW is currently experiencing record-breaking flooding, after experiencing back-to-back extreme weather events in the last few years. 

It is critical to understand that these kinds of disasters are no longer simply “natural”. Extreme rainfall events have become more frequent and intense in Australia, and communities are suffering the consequences. Again and again. 

It is vital that emergency services, journalists and media outlets, governments and communities understand why these events are occurring with increasing frequency and ferocity so that we can tackle the root cause – pollution from coal, oil and gas – as well as prepare for more destructive disasters into the future.

There are at least three ways that climate change is influencing the intensity of these floods:

1. More water in the atmosphere leads to more heavy downpours

As the climate heats, the global atmosphere holds more moisture. The total amount of water vapour in the atmosphere reached a record value in 2024, at about 5% above the 1991–2020 average. With the atmosphere laden with more moisture, extreme downpours have become more common. 

The latest research for Australia shows that more rain is falling during extreme events. We are experiencing:

• 7-28% more rain for shorter duration rainfall events (the type of events associated with flash flooding); and
• 2-15% more rain for longer duration events. 

This range is much higher than the 5% figures that are used in existing flood planning standards by the likes of policy makers, engineers and urban planners.

2. A hotter climate means more energy for storms

A hotter, wetter and more energetic climate also means there is more energy to fuel storms that generate heavy rainfall. Since July 2024, sea surface temperatures in Australia have been the warmest or second warmest on record for each respective month. That means the energy available to power storms has also increased – largely due to rising ocean temperatures from the burning of fossil fuels.

3. Changing “atmospheric rivers” and extreme rain

A near-stationary high pressure system in the Tasman Sea has contributed to the persistence of this rainfall event, stalling a moist, easterly flow of air over the NSW coast. Similarly, in major flooding events in 2021 and 2022, a “blocking high” contributed to the severity of flooding. Emerging research suggests that climate change may affect the drivers of multi-day rainfall extremes, including a “blocking high” (CSIRO and BoM 2024). This is an important area for further research.

What is the impact of extreme flooding on Australian communities?

Floods have been the most damaging disasters in Australia over the last decade. Floods are New South Wales’ deadliest disaster and cause more injuries than other extreme weather events. Immediate impacts of floods include property damage, destruction of crops and livestock, clean up costs and emergency response.

The increasing frequency and severity of extreme events means communities are facing successive disasters with little time in between to recover.

“We’ve had back-to-back flood events since the 2019-20 fires. These are compounding events for communities still in recovery; it’s what we expect with people being in a constant state of disaster recovery under climate change”

– Andrew Gissing, Chief Executive of Natural Hazards Research Australia.

The MidCoast Local Government Area has experienced back-to-back disasters over the last six years, needing support for disaster recovery on 13 occasions, including with the community experiencing extensive damage during Black Summer, the 2021 East Coast floods and again following this latest extreme flood event. Communities are picking up the pieces over and over again.

Much of the affected area has been identified as at high risk of flooding, with insurance becoming too expensive for many home owners in most at risk areas. 

Emergency services are reporting being overwhelmed by the “increasing frequency, intensity and destructiveness of out of control fires, floods and storms”.

Australia’s climate disasters in 2025

This event comes as Australia has already experienced a succession of major climate disasters in the first five months of 2025. As a nation, we are experiencing “climate whiplash” – being hurled violently from one extreme to another. This year:

• Ningaloo Reef has experienced its first mass bleaching event;
• The Great Barrier Reef has experienced the sixth mass coral bleaching in nine years; 

• Ex-Tropical Cyclone Alfred was exacerbated by hot ocean temperatures, a wetter atmosphere and higher seas. The unusually slow speed led to greater deluges over areas it passed, while the southerly track brought risks to communities not usually exposed to cyclones;
• Western Queensland floods, partly driven by Ex-Tropical Cyclone Alfred, were likely the largest on record; 
• Swathes of South Australia, Victoria, Tasmania and Western Australia are in the grip of drought as they experience some of the lowest rainfall totals on record.\; and
• South Australia’s Algae Bloom is driven by an underwater heatwave which has led to unprecedented animal deaths.

What does the future look like?

The frequency of intense rainfall events is expected to almost double with each degree of global heating. However, we can still influence how much worse things become if we act urgently. The severity of the climate crisis depends on how swiftly and deeply we slash climate pollution. This decade is critical.

Appendix: Disaster Recovery Funding Arrangement Activations for local government areas impacted by the May 2025 NSW floods (February 2019 – May 2025)

Disaster Recovery Funding Arrangement (DRFA) activations for local government areas data can be accessed here.

Information on the local government areas receiving DRFA assistance can be found here.

Image credit: NSW SES, Facebook