澳洲雨林發生轉變：從碳匯變成碳源！

Australia's tropical rainforests have always played a key role in helping the planet by acting as 'carbon sinks. ' This means they absorb more carbon dioxide from the atmosphere than they release, which helps slow down climate change. However, a new study has revealed that these rainforests are now releasing more carbon than they absorb, making them the first in the world to do so. This change is linked to climate change, with rising temperatures and more extreme weather events causing more trees to die than new ones can grow.

The research, led by Dr Hannah Carle from Western Sydney University, looked at nearly five decades of data from 20 forests in Queensland. The findings showed that the number of tree deaths has increased because of hotter temperatures, drier air, and more frequent and severe cyclones. When trees die, their trunks and branches, known as woody biomass, start to release carbon into the atmosphere. This shift began about 25 years ago, turning the forests from carbon absorbers into carbon emitters. Dr Carle explained that this has serious consequences for global efforts to reduce emissions, as many climate models rely on forests to help offset the carbon produced by burning fossil fuels.

Australia is one of the world's largest polluters per person and has recently pledged to cut its emissions by at least 62 percent compared to 2005 levels over the next decade. Despite this promise, the country still depends heavily on fossil fuels, and the government has allowed major gas projects to continue. Scientists warn that if Australia's rainforests continue to release more carbon, other tropical forests around the world could follow the same pattern. This would make it even harder to fight climate change and protect communities from its effects. The study's authors say more research is needed to understand how other forests might respond, but the evidence from Australia is a warning sign for the rest of the world.