According to a new report from the U.S. Agriculture Department, American forests are facing a concerning decline in their ability to absorb carbon dioxide, which could exacerbate global warming instead of mitigating it. The report attributes this loss to the destruction caused by natural disasters and the reduced carbon absorption capacity of older forests.
The study predicts that after 2025, forests' carbon absorption will start declining significantly, resulting in potential emissions of up to 100 million metric tons of carbon annually. As decaying trees release more carbon than forests can absorb, they might become a "substantial carbon source" by 2070, as stated in the USDA report.
Currently, U.S. forests absorb approximately 11% of the nation's carbon emissions, equivalent to 150 million metric tons of carbon annually. This is comparable to the combined emissions from 40 coal power plants.
The report's findings suggest that the loss of forests as natural carbon absorbers will necessitate faster emission reductions in the U.S. to achieve net-zero emissions. Lynn Riley, a senior manager of climate science at the American Forest Foundation, emphasizes the significance of this loss, indicating that forests are valuable tools in decarbonization efforts.
The reduced capacity for carbon absorption is influenced, in part, by the increasing frequency and intensity of natural disasters like wildfires, tornadoes, and hurricanes, linked to rising global temperatures. These disasters destroy forestland, disrupting ecosystems and weakening the carbon-absorbing ability of the forests.
Additionally, the ongoing development in forested regions, along with aging forests, contributes to the problem. As people move into the so-called wildland urban interface and older trees absorb less carbon than younger ones, the overall carbon-holding potential of forests diminishes.
Riley suggests that more aggressive forest management practices could help by selectively removing older trees to make way for younger ones, which have higher carbon absorption rates. However, she emphasizes the need for a thorough assessment of each forest before implementing such measures, likening forest management to prescribing the right treatment for a patient.