- by M Santos
- The Guardian
- Issue #2151
Photo: Markus Spiske – Unsplash License.
The Mid-North Coast of NSW recently experienced record breaking flooding, after experiencing back to back extreme weather events in the last few years. Such 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, media, governments, and communities understand why these events are occurring with increasing frequency and ferocity to ensure that we can both tackle the root cause – pollution from coal, oil, and gas – as well as prepare for more destructive disasters into the future,” Climate Council CEO Amanda McKenzie said.
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 level in 2024, at about 5% above the 1991–2020 average. With more moisture in the atmosphere, extreme downpours have become more common.
More rain is falling during extreme events. The amount of rain is much higher than the 5% figures that are used in existing flood planning standards used by policy makers, engineers and urban planners.
2. A hotter, wetter and more energetic climate 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. 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 ‘blocking high’ contributed to the severity of flooding. Blocking highs are strong high pressure systems which have formed further south than usual and remain near stationary for an extended period of time. These highs essentially block the west to east progression of weather systems across southern Australia.
IMPACT ON COMMUNITIES
Floods have been the most damaging disasters in Australia in the last decade. Immediate impacts 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,” McKenzie noted.
The Mid Coast Local Government Area has experienced back to back disasters over the last six years, needing support for disaster recovery on 13 occasions. 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 being overwhelmed by the increasing frequency, intensity and destructiveness of out of control fires, floods and storms.
The frequency of intense rainfall events is expected to almost double each degree of global heating. However, we can still influence how much worse things become. The severity of the climate crisis depends on how swiftly and deeply we slash climate pollution. This decade is critical.
Australia has already experienced a succession of major climate disasters in the first five months of 2025:
Ningaloo Reef has experienced its first mass bleaching event.
The Great Barrier Reef has experienced the 6th 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.
West-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.
