How the ‘Big Dry’ is threatening Western Australia’s ecosystems
In the face of the South West’s ‘Big Dry,’ experts reveal alarming trends of declining rainfall and rising temperatures. From caves that tell climate stories through stalagmites to the devastating impacts on iconic forests and wildlife, it’s clear that urgent climate action is needed to protect Western Australia’s ecosystems and beyond.
Last week, we had the pleasure of attending the final Sundowner Session organised by Nature Conservation Margaret River at The Heart, Margaret River. A panel of three expert speakers, alongside Nature Conservation’s director Drew, shared valuable insights into today’s drying climate and its direct impact on ecosystems across Western Australia, particularly the South West.
Here’s what we learned.
Stalagmites: time machines for tracking climate change
Dr. Pauline Treble, Senior Research Scientist at the Australian Nuclear Science and Technology Organisation (ANSTO), has spent years studying local caves.
Dr. Treble explained that stalagmites act as time machines, revealing insights into past climate changes. Her team has set up an underground lab inside one of these caves, where they monitor surface-to-cave drip water processes. By studying chemical changes in the stalagmite layers, they discovered a significant decline in “fast drip” water flows since the 1980s — an indicator of good rains.
We’re now facing the lowest rainfall replenishment of groundwater in 800 years.
Groundwater is an essential water source for plants, trees, and other vegetation. It supports microbial activity in the soil, helps reduce erosion, and maintains soil health while regulating temperature. Most importantly, groundwater ensures that plant roots have access to moisture, even during dry periods, helping vegetation survive droughts and sustain growth.
Unprecedented heat: the growing threat of fire
Dr. Joe Fontaine, a fire ecologist and climate change expert from Murdoch University, shared alarming statistics. The number of days exceeding 40°C has more than doubled in the Perth area since the 1940s. This prolonged heat, paired with historically low soil humidity, is placing unprecedented stress on local ecosystems.
One concerning example is the die-off of the iconic Jarrah forest. After the low winter rainfall of 2010 and a hot, dry summer, the trees began showing signs of severe drought. Fontaine’s research focuses on how environmental disturbances such as fire, drought or invasive species alter ecosystems and impact their capacity to recover.
Wildlife at risk: the ongoing impact of drought
FAWNA President Suzie provided a heartbreaking perspective on the dry conditions’ impact on wildlife. As wetlands dry up, black swan cygnets are being stranded and forced to walk towards the ocean in search of water. Meanwhile, possums are suffering severe burns from walking on overheated surfaces like solar panels.
FAWNA has seen a dramatic increase in the number of Western Ringtail Possums with burned paws. In 2022, they recorded 23 cases, but this number spiked to over 70 in 2023 due to rising temperatures. As small mammals struggle to survive, the food chain is disrupted, causing wider ecosystem fragmentation.
A clear call to climate action
Each expert’s input made it clear: the urgency of climate action cannot be overstated.
As Joe Fontaine pointed out, the warning signs from 2011 — low rainfall and extreme heat — are repeating today. But it’s not too late to make a change.
Thank you to the team at Nature Conservation Margaret River for such an insightful session. We look forward to more to come!