Is Climate Change Causing Unusual Tree Deaths Across Australia?

Tree deaths across Australia are accelerating as a result of climate change, according to a study published in Nature Plants in January 2026.

The study, “Pervasive increase in tree mortality across the Australian continent,” finds that tree mortality rates have risen consistently across all major forest types, from tropical savannas in the north to cool temperate forests stretching from Tasmania to New South Wales.

A continent-wide rise in tree mortality

Researchers analysed 83 years of forest inventory records alongside independent data from more than 200,000 individual trees. The dataset spans 958 species across over 2,700 plots nationwide, offering one of the most comprehensive assessments of “background tree mortality” deaths not directly caused by logging, land clearing, or fire.

The findings reveal a clear and troubling trend: tree death rates have increased across every forest biome studied. Tropical savannas experienced the most rapid rise, with mortality increasing by 3.2% per year between 1994 and 2018.

Warm temperate forests saw a 1.9% annual increase between 1941 and 2023, while tropical rainforests recorded a 1.8% rise between 1963 and 2023.

Cool temperate forests, though comparatively less affected, still experienced a 1.0% annual increase between 1965 and 2023.

Climate change is a key driver

The researchers link the rising mortality rates to increasing temperatures. Since the pre-industrial period, the Earth has warmed by an average of 1.2°C, with most of this warming occurring over the past five decades.

Higher temperatures place trees under physiological stress, reducing growth and increasing vulnerability to drought and heat-related damage.

The study warns that continued increases in tree mortality could significantly undermine forests’ capacity to sequester carbon dioxide, weakening one of nature’s most important climate-regulating mechanisms.

Implications for carbon storage and ecosystems

Senior author Distinguished Professor Belinda Medlyn of the Hawkesbury Institute for the Environment emphasised the broader consequences of the findings.

“Australians rely on forests for a wide range of ecosystem services, from cultural values and recreation to timber for housing,” she said. “Increasing tree mortality in our unique forests will affect all of these. A particular concern is that forests’ ability to store carbon will decline, with serious implications for Australia’s net carbon balance.”

Globally, forests absorb roughly one-third of human carbon dioxide emissions each year. If mortality continues to rise while tree growth stagnates, this buffering capacity will erode.

Recent evidence from northern Australia’s tropical rainforests already shows this shift underway, with some forests transitioning from net carbon sinks to net carbon sources.

Such changes could weaken the planet’s ability to absorb emissions and intensify climate feedback loops, further narrowing the window for stabilising the global climate.