In a groundbreaking study published in the journal Nature, Australia’s tropical rainforests have been identified as the first globally to transition from carbon sinks to carbon emitters, a shift attributed to the escalating impacts of climate change. Traditionally, rainforests function as carbon sinks, absorbing more carbon dioxide than they release, with new tree growth offsetting emissions from decaying vegetation. However, research analyzing data from Queensland’s forests reveals that extreme temperatures have accelerated tree mortality, disrupting this balance. Dr. Hannah Carle of Western Sydney University, the study’s lead author, emphasized that these findings challenge existing models that overestimate tropical forests’ capacity to mitigate fossil fuel emissions. The study, spanning 49 years of data from 20 Queensland forests, highlights that increased tree deaths have turned woody biomass—dead trunks and branches—into carbon sources rather than absorbers, a trend that began approximately 25 years ago. Dr. Carle warned that forests, which play a critical role in mitigating climate change by absorbing carbon dioxide, are now under threat. The research also links rising tree mortality to climate-driven factors such as extreme heat, atmospheric dryness, and prolonged droughts. Additionally, the study notes that more frequent and severe cyclones have further exacerbated tree loss and hindered new growth. Dr. Carle described Australia’s rainforests as a ‘canary in the coal mine,’ signaling a potential global trend. Senior author Patrick Meir echoed these concerns, suggesting that other tropical forests may follow suit, though further research is needed for a comprehensive assessment. Australia, one of the world’s highest per capita polluters, recently pledged to reduce emissions by 62% from 2005 levels by 2033. However, the nation continues to face criticism for its reliance on fossil fuels, exemplified by the government’s approval of a 40-year extension for Woodside’s North West Shelf gas project. A recent climate report also revealed that Australia has already surpassed 1.5°C of warming, with communities facing escalating climate risks. This study underscores the urgent need for global action to address the dual crises of deforestation and climate change.
Australia’s rainforests are releasing more carbon than they absorb, warn scientists
