  Between 2019 and 2020, during the country's hottest and driest year on
record, Australia experienced a dramatic bushfire season, with catastrophic
ecological and environmental consequences. Several studies highlighted how such
abrupt changes in fire regimes may have been in large part a consequence of
climate change and other anthropogenic transformations. Here, we analyze the
monthly evolution of the burned area in Australia from 2000 to 2020, obtained
via satellite imaging through the MODIS platform. We find that the 2019-2020
peak is associated with signatures typically found near critical points. We
introduce a modeling framework based on forest-fire models to study the
properties of these emergent fire outbreaks, showing that the behavior observed
during the 2019-2020 fire season matches the one of a percolation transition,
where system-size outbreaks appear. Our model also highlights the existence of
an absorbing phase transition that might be eventually crossed, after which the
vegetation cannot recover.
