![]() The story on land is also alarming, with intensifying heatwaves and chronic drought. Smooth Marron moving as a group in a reservoir. To protect remaining freshwater species we must develop perennial water refuges in places such as farm dams. As river flow falls to a trickle, fish can no longer migrate to spawn, and it’s only a short march from there to extinction. Most native freshwater fish in the southwest are now officially considered “threatened”. The drying also makes it very hard for animals and birds to find water. The loss of water has even killed off common river invertebrates, such as the endemic Western Darner dragonfly, with most now found only in the last few streams that flow year round. For example, the number of invertebrate species in 17 lakes in WA’s wheatbelt fell from over 300 to just over 100 between 19. It means many rivers and lakes now dry out through summer and autumn, causing major problems for freshwater biodiversity. That might not sound dangerous, but the drop means river flows have already fallen by an alarming 70 per cent. As climate change worsens, these winds are projected to get more intense, bringing still more heat.ĭrying threatens wildlife, wine and wheatĪnnual rainfall in the southwest has fallen by a fifth since 1970. The southwest already has very hot days in summer, thanks to heat brought from the desert’s easterly winds. Almost all climate models project a further drop in winter rainfall of up to 30 per cent across most of the southwest by 2100, under a high emissions scenario. Cumulative number of days over 40° at Perth Airport over 30-year periods between 1910-1939 (historic) and 1989-2018 (current). Australian Bureau of Meteorology.Īnd remarkably, a 1℃ increase in the average global temperature over the last century has already more than doubled the days over 40℃ in Perth. Southwest WA runs roughly from Kalbarri to Esperance and is known for its Mediterranean climate with very hot and dry summers and most rainfall in winter.īut every decade since the 1970s, the region’s summertime maximum temperatures have risen 0.1-0.3℃, and winter rainfall has fallen 10-20 millimetres. Dr Joe Fontaine, Author provided Hotter and drier Hooker’s Banksia is an iconic West Australian species. Read more: Australia's south west: a hotspot for wildlife and plants that deserves World Heritage status But climate heating means this remarkable biological richness is now imperilled - a threat that will only increase unless the world takes action. They evolved in isolation over millions of years, walled off from the rest of Australia by desert. Most freshwater species and around 80 per cent of marine species, including 24 shark species, live nowhere else on Earth. Species include thousands of endemic plant species and animals such as the quokka, numbat and honey possum. The region’s wildlife and plants are so distinctive and important, it was listed as Australia’s first global biodiversity hotspot. ![]() ![]() ![]() ![]() But for southwest Western Australia, climate change is also an existential threat. The Intergovernmental Panel on Climate Change warns this will continue as emissions rise and the climate warms.ĭiscussion of Australian ecosystems vulnerable to climate change often focuses on the Great Barrier Reef, as well as our rainforests and alpine regions. Since 1970, winter rainfall has declined up to 20 per cent, river flows have plummeted and heatwaves spanning water and land have intensified. The southwest of Western Australia has been identified as a global drying hotspot. We know climate change is already happening and nowhere is the damage more stark than in Australia’s southwest. It often happens in these extreme events, where a large population of something like mussels can die," Pinsky said.In a few days world leaders will descend on Glasgow for the United Nations climate change talks. "Species are shifting towards the poles of the Earth at about 60 kilometers per decade, and it doesn't happen slowly, bit by bit. Malin Pinsky, an associate professor of marine biology at Rutgers University, said the extreme heat contributes to a "massive reorganization of ocean life." The die-off could have ripple effects beyond the shore "If it happens that frequently, the system won't have time to recover in between the die-offs," he said. Though heat waves have affected marine life in the past, Harley said temperatures reaching more than 100 degrees Fahrenheit like they did last weekend in the Pacific Northwest are "exceptionally rare." But with climate change, he's seen estimates from other scientists that similar heat waves could start occurring once every five to 10 years. Harley has been tracking mussels and other sea creatures in the aftermath of the heat wave that hit the Pacific Northwest.Ĭhristopher Harley/University of British Columbia ![]()
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