The emerging threat of hot drought in Western Australia

Droughts severely affect our environments, biodiversity, production systems and communities. When assessing droughts, we generally consider deficits in rainfall, subsurface water, water for crops and water for societies, economies and the environment. Due to climate change, increasing temperatures and more frequent and prolonged drought events are occurring in Australia and globally. When droughts and extreme temperatures occur together in the same space and time, it results in hot droughts, a phenomenon that can be devastating for flora, fauna and society. Here, we map hot drought events across Western Australia since 1889. Our results indicate that significant hot droughts have become more frequent, with the most severe hot droughts on record occurring within the last five years. Additionally, hot droughts within the last four decades, and particularly within the last two decades, affected a significantly larger area than the average for the historical record. With 2024 already on track to be the driest and hottest year on record in southwest Western Australia, natural resource managers must prepare for the increasing frequency and severity of hot droughts. Implication for ManagersO_LIAustralia and the world are experiencing more frequent and intense droughts and heatwaves. Hot droughts, characterised by simultaneous extreme water scarcity and extreme high temperatures, are particularly devastating. C_LIO_LIWe mapped hot drought events in Western Australia since 1889, revealing a recent surge in occurrence concentrated in the most recent five years. Statistical testing indicates that hot droughts within the most recent 20 and 40 years were significantly larger in extent compared to the historical average. C_LIO_LIWith the first half of 2024 exceptionally dry and hot, proactive strategies are imperative for natural resource managers. C_LI