The season’s bushfires have burned more than 20% of Australia’s forests – an unprecedented percentage to burn on any continent in a single season, an academic study has found.

Forest fire losses in other continents have been well below 5%, apart from Asian and African sections of dry broadleaf forests which have recorded up to 9%.

“These unprecedented fires may indicate that the more flammable future projected to eventuate under climate change has arrived earlier than anticipated,” the paper, published by academics Matthias M. Boer, Víctor Resco de Dios and Ross A. Bradstock, says.

Eastern Australia’s forests, dominated by eucalypts, are among the most fire-prone in the world. Yet while major fires are relatively common, only small percentages of this forest biome [a community of plants and animals that have common characteristics] burn each year, typically below 2% even in more extreme fire seasons.

The researchers have found 21% of Australia’s temperate broadleaf and mixed forest biome was wiped out by the spring/summer fires, excluding Tasmania and the remainder of the season.

Between September and early January around 5.8 million hectares of forest burned in NSW and Victoria bin a series of “mega-fires”. The Gospers Mountain fire near Sydney has burned more than 510,000 hectares since ignition by lightning on October 26. It is the largest forest fire recorded in Australia.

Widespread drought meant that naturally occurring firebreak like moist gullies, swamps or south-facing slopes, were dried out, encouraging large-scale fires.

The scientists say this meant the area of forest exceeding critical flammability thresholds was larger and more prolonged than recorded in the past 30 years. This finding has been supported by the NSW Department of Planning, Industry and Environment.