PLEA Network

16 October 2025, The Conversation: A crucial store of carbon in Australia’s tropical forests has switched from carbon sink to carbon source. One approach to help fight climate change is to protect natural forests, as they absorb some atmospheric carbon released by burning fossil fuels and store large volumes of carbon. Our new research on Australia’s tropical rainforests challenges the assumption that they will keep absorbing more carbon than they release. We found that as climate change has intensified over the past half-century, less and less carbon has been taken up and converted to wood in the stems and branches of the trees in these forests. Woody biomass is a large and relatively stable store of carbon in forests, and acts as an important indicator of overall forest health. The effect has been so pronounced that the woody biomass of these forests has gone from being a carbon sink to a carbon source. This means carbon is being lost to the atmosphere due to trees dying faster than it is being replaced by tree growth. This is the first time woody biomass in tropical forests has been shown to switch from sink to source. Our research indicates the shift likely happened about 25 years ago. It remains to be seen whether Australian tropical forests are a harbinger for other tropical forests globally. Read more here