Carbon Mitigation Estimates Slashed as Study Finds Reforestation Land is Two-Thirds Less Than Previously Thought
GLOBAL – October 2, 2025 – New research published in the journal Science warns that global pledges to plant billions of trees as a cornerstone of carbon reduction may be based on wildly optimistic land and sequestration estimates. The study found that the amount of land previously deemed suitable for forestation an area about the size of India shrank by as much as two-thirds when vital environmental and social constraints were factored in.
The research co-authored by Josep “Pep” Canadell, executive director of the Global Carbon Project, determined that once adverse impacts on biodiversity, food security, and water resources are accounted for the potential for existing tree-planting pledges to store an estimated 40 gigatons of carbon by 2050 drops significantly to just 12.5 gigatons.
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