Windhoek: Australia's tropical rainforests have transitioned from a carbon sink to a net source of carbon dioxide emissions, a change primarily attributed to rising temperatures, air dryness, and droughts associated with human-driven climate change. The research, published in the journal Nature, indicates that these rainforests are the first of their kind globally to exhibit such a response to climate change.

According to Namibia Press Agency, a statement by Australia's Western Sydney University (WSU) detailed the findings, emphasizing the critical role forests play in mitigating climate change by absorbing carbon dioxide. Study lead author Hannah Carle from WSU's Hawkesbury Institute for the Environment, part of an international research team including members from the Australian National University, pointed out that the capacity of these forests to act as carbon sinks is now under threat.

Tropical forests are among the world's most carbon-rich ecosystems, typically absorbing more carbon than they emit. However, the study reveals that the ability of woody biomass, including tree trunks and branches in Australia's tropical rainforests, to maintain their role as carbon sinks is diminishing. This shift is primarily due to increased tree mortality driven by climate change factors, such as extreme temperatures, atmospheric dryness, and droughts.

Carle commented on the unexpected nature of the findings, noting that despite higher carbon dioxide levels-expected to facilitate tree growth and enhance carbon sink capacity-the associated increase in carbon emissions to the atmosphere is not being offset by increased tree growth. The study's findings have significant implications for emissions reduction targets, which partly rely on the expected capacity of ecosystems to absorb emissions and mitigate climate change.

Carle highlighted that current models might overestimate the capacity of tropical forests to counterbalance fossil fuel emissions. The study also notes that cyclones, which have become more severe due to climate change, further suppress the carbon sink capacity of woody biomass in these forests and are impacting areas further southward.

The researchers emphasize the necessity for continuous monitoring to determine whether similar changes will occur in other tropical forests worldwide, indicating an area that requires further investigation.