2019–20 Australian bushfire season

The 2019–20 Australian bushfire season, or Black Summer, was one of the most intense and catastrophic fire seasons on record in Australia. It included a period of bushfires in many parts of Australia, which, due to its unusual intensity, size, duration, and uncontrollable dimension, was considered a megafire by media at the time. Exceptionally dry conditions, a lack of soil moisture, and early fires in Central Queensland led to an early start to the bushfire season, beginning in June 2019. Hundreds of fires burnt, mainly in the southeast of the country, until May 2020. The most severe fires peaked from December 2019 to January 2020.

The fires burnt an estimated 24.3 million hectares (243,000 square kilometres), destroyed over 3,000 buildings (including 2,779 homes), and killed at least 34 people. According to the University of Tasmania’s Menzies Institute, bushfire smoke was responsible for more than 400 deaths, reported by the Medical Journal of Australia.

In December 2023 the Sydney Morning Herald reported a large volume of smoke in the Sydney basin resulted from the so called Gospers Mountain "megablaze" after the NSW Rural Fire Service lost control of back burning in November and December 2019. It was claimed that three billion terrestrial vertebrates – the vast majority being reptiles – were affected and some endangered species were believed to be driven to extinction. The cost of dealing with the bushfires was expected to exceed the A$4.4 billion of the 2009 Black Saturday fires, and tourism sector revenues fell by more than A$1 billion. Economists estimated the bushfires – Australia's costliest natural disaster in history – may have cost over A$78–88 billion in property damage and economic losses. Nearly 80% of Australians were affected by the bushfires in some way. At its peak, air quality dropped to hazardous levels in all southern and eastern states, and smoke had been moving upwards of 11,000 kilometres (6,800 mi) across the South Pacific Ocean, impacting weather conditions in other continents. Satellite data estimated the carbon emissions from the fires to be around 715 million tons, surpassing Australia's normal annual bushfire and fossil fuel emissions by around 80%.

From September 2019 to March 2020, fires heavily impacted various regions of the state of New South Wales (NSW). In eastern and north-eastern Victoria, large areas of forest burnt out of control for four weeks before the fires emerged from the forests in late December. Multiple states of emergency were declared across NSW, Victoria, and the Australian Capital Territory. Reinforcements from all over Australia were called in to assist fighting the fires and relieve exhausted local crews in NSW. The Australian Defence Force was mobilised to provide air support to the firefighting effort and to provide manpower and logistical support. Firefighters, supplies and equipment from Canada, New Zealand, Singapore and the United States, among others, helped fight the fires. An air tanker and two helicopters crashed during operations, killing three crew members. Two fire trucks were caught in fatal accidents, killing three firefighters.

By 4 March 2020, all fires in NSW had been extinguished completely (to the point where there were no fires in the state for the first time since July 2019), and the Victoria fires had all been contained. The last fire of the season occurred in Lake Clifton, Western Australia, in early May.

There has been considerable debate regarding the underlying cause of the intensity and scale of the fires, including the role of fire management practices and climate change, which during the peak of the crisis attracted significant international attention, despite previous Australian fires burning much larger areas (1974–75) or killing more people (2008–09). Politicians visiting fire impacted areas received mixed responses, in particular Prime Minister Scott Morrison. An estimated A$500 million was donated by the public at large, international organisations, public figures and celebrities for victim relief and wildlife recovery. Convoys of donated food, clothing and livestock feed were sent to affected areas.