Forests, long considered a critical natural buffer against carbon emissions, may lose much of their carbon-absorbing power as the planet warms. A new model published in the journal Science suggests that climate-driven temperature increases could reduce forest carbon storage by as much as 30% by the end of the century, even as carbon dioxide levels rise.
The finding upends a key assumption in many climate forecasts: that forests will grow faster with more CO2. Researchers found that warmer temperatures actually inhibit tree growth, counteracting the fertilization effect of extra carbon. This feedback loop could weaken the land carbon sink, a cornerstone of global climate mitigation strategies.
According to the model, which integrates decades of ecological data, the decline in forest growth is most pronounced in tropical regions, where already-high temperatures push trees closer to their thermal limits. Boreal forests may also see stunted growth, though the impact varies by species and local conditions.
The implications are stark: if forests store less carbon, more CO2 will remain in the atmosphere, accelerating warming. Nations relying on forest-based carbon offsets may find their climate pledges harder to meet. The model highlights a pressing need to reduce emissions at the source rather than depending on natural sinks.
“We’re essentially weakening our greatest ally,” said lead author Dr. Anna Ramirez. “Forests can’t save us from ourselves if we keep raising the temperature.”