The 2019-20 fires burned with unprecedented intensity through a total of 24 million hectares (59 million acres), an area the size of the U.K., and killed or displaced up to 1.5 billion animals, according to research published in 2021.

https://news.mongabay.com/2024/03/studies-still-uncovering-true-extent-of-2019-20-australia-wildfire-catastrophe/#:~:text=The%202019%2D20%20fires%20burned,to%20research%20published%20in%202021.