Is Climate Change the primary cause of the 2019/20 bush fires in Australia?
Increasing population density in bush areas is more important than Climate Change in the increased severity of fires in Australia.
Researchers in a 2015 study found that the number of ignitions (fires) increased substantially where human population density was greatest despite having less bush to burn. As the Australian population moves increasingly into bush areas, they are causing more fires.
It is only in sparsely populated areas that a human population increases fire frequency, instead reducing it considerably as density rises.
A 2014 study in Biogeosciences found that humans only increase fire frequency when population density remains below 0.1 people per km2. Through active land management activities (deliberate burning, active fire suppression), greater population density reduces the risk of fire.
The fires were predicted by the Australian Bureau of Meteorology due to the Indian Ocean Dipole entering a severe positive phase.
The Indian Ocean Dipole goes through natural positive and negative phases that have a major impact on rainfall levels across the ocean. Positive Dipoles result in drought conditions in the eastern Indian Ocean, resulting in conditions more prone to fires as seen in Australia.
The Indian Ocean Dipole is being impacted by global climate change, with extreme events caused by the dipole predicted to rise.
A 2014 study published in Nature by scientists in Australia, India, China and Japan projected that the frequency of extreme positive dipole events would increase this century from one every 17.3?years to one every 6.3?years due to increasing greenhouse emissions.
Human actions cause the majority of bush fires in Australia, both through deliberate arson and by accident.
An International Journal of Wildland Fire study in 2015 found that of 130,000 fires recorded between 1997-2009 with a known cause (69%), 87% were caused by direct human actions. 47% of these were accidental (cigarettes, campfires, sparks from equipment), and 40% deliberately lit.