Climate Change and El Ni?o: The Underlying Causes of Extreme Heatwaves in Western Australia
The climate in Western Australia has undergone significant changes over the past few decades, with pronounced warming and a decline in rainfall. These changes are not isolated phenomena but part of a global trend influenced by both natural and anthropogenic factors. This article delves into the roles of climate change and the El Ni?o weather pattern in contributing to the extreme heatwaves experienced in Western Australia, particularly in the South West (SWWA) region.
The Impact of Climate Change on Western Australia
The mean climate in Western Australia has shifted, making the region warmer and drier over the past fifty years. According to the Climate Council, the influence of El Ni?os is primarily felt in eastern Australia, leading to warmer temperatures and reduced rainfall, which heighten the risk of extreme heat and bushfires. However, the main natural factor affecting Western Australia is the Indian Ocean Dipole (IOD), which is currently strong. This natural phenomenon, combined with climate change, exacerbates heatwaves and drought conditions in the region.
Despite the frequent claims by deniers, the evidence for anthropogenic global warming is overwhelming. The levels of CO2 in the atmosphere are increasing at a rate 100 times faster than they did during the last glacial period, and temperatures are rising 40 times faster. This climate change is the fundamental cause of increasing heatwaves and other extreme weather events around the world, including in Western Australia.
Extreme Heatwaves in Western Australia
Western Australia is currently experiencing its hottest summer on record. On Sunday, February 18, 2024, Carnarvon recorded a temperature of 49.9°C, breaking its temperature record by over two degrees and surpassing the highest temperature globally for the year so far. Geraldton also reached 49.3°C, while the capital city of Perth recorded a temperature of 42.9°C. This event has resulted in six days of temperatures exceeding 40°C in the same month, a record that set a new benchmark for the region.
The combination of climate change and the IOD has made the southwestern part of Western Australia even warmer and drier. The south-west of Western Australia (SWWA) has experienced a decline in rainfall over the past 28 years, with none of the ten dams supplying Perth's metropolitan area spilling water. This has led to significant water stress, particularly in the northern jarrah forest, where water sources have become scarce.
How El Ni?o Contributes to Extreme Heatwaves in Western Australia
While El Ni?o does play a role in warming certain regions, especially in eastern Australia, its impact on Western Australia is less pronounced. The southeast Indian Ocean has a more significant influence on the climate in Western Australia. The IOD, as mentioned earlier, is currently at its strongest, leading to drier and more thermally favorable conditions for extreme heat.
The El Ni?o phenomenon, characterized by the warming of sea surface temperatures in the eastern Pacific, can influence weather patterns across the globe. However, for Western Australia, the IOD is the primary driver of extreme heat. The IOD can lead to higher temperatures and reduced rainfall, creating ideal conditions for heatwaves to form. In the current context, the IOD, together with climate change, is contributing to the intensity and frequency of heatwaves in Western Australia.
Conclusion
The extreme heatwaves in Western Australia are a result of a complex interplay between climate change and natural weather patterns such as the Indian Ocean Dipole. While El Ni?o has its impact, the IOD is the predominant natural factor influencing the region's weather. Continued efforts are needed to address the root causes of climate change and adapt to the changing climate to mitigate the effects of extreme heatwaves and protect vulnerable ecosystems and communities.