Genetic engineering has paved the way for a new generation of trees capable of capturing and storing more CO2 for longer. Recent techniques such as CRISPR-Cas and base editing enable the DNA of plants to be modified with great precision, improving their photosynthetic efficiency, accelerating their growth, and promoting the development of deeper roots that can store carbon in the soil for centuries.
Genetic modification of trees is not new, but until recently, it has mainly been driven by productivity goals. In 2015, Brazil approved the commercial use of a genetically modified eucalyptus tree that grew 20% faster and produced more cellulose, intending to increase the efficiency of industrial plantations. Now, these more advanced gene-editing techniques are beginning to be used for climate purposes. Plants act as carbon sinks, absorbing CO₂—one of the main greenhouse gases—from the atmosphere during photosynthesis and storing it in their trunks, leaves, roots and the surrounding soil.
A recent initiative in this area is the Living Carbon project, which has developed genetically modified poplars that photosynthesise and decompose more efficiently. In laboratory tests, some specimens produced 53% more above-ground biomass (i.e. trunks, branches and leaves) and stored up to 27% more carbon than conventional trees. Since 2023, pilot plantations have been established in the southeast of the United States, exploring potential applications in degraded areas such as former mining sites. Another example is the Salk Institute's Harnessing Plants project, which aims to genetically engineer plant species to increase their production of suberin—a natural compound that slows decomposition and enables long-term carbon storage in soil.
However promising this innovation may be, there are significant challenges. Some experts warn of potential ecological impacts such as unintended gene flow, reduced biodiversity and increased water use. These factors could prove problematic in regions where water is scarce. Nevertheless, if managed carefully, supertrees could become a valuable tool for expanding carbon sinks and strengthening climate action in the years to come.
For further information, see: Boyce Upholt. “Inside the quest to engineer climate-saving supertrees.” MIT Technology Review; Nature Biotechnology. “Brazil Approves Transgenic Eucalyptus.” Nature Biotechnology 33, 2015; Salk Institute. “Harnessing Plants Initiative – Research.” Salk Institute; and Tao, Yumin, et al. “Enhanced photosynthetic efficiency for increased carbon assimilation and woody biomass production in engineered hybrid poplar.” Forests 14, n.º 4, 2023.
CRISPR-Cas and base editing are gene-editing techniques developed over the past decade. Unlike traditional methods, they allow targeted, rapid modifications of specific DNA sequences without the need to insert genes from other species. Their precision has opened up new possibilities for enhancing specific functions in plants. For more detail on these techniques, see: Kim, Jin-Soo, and Jia Chen. “Base editing of organellar DNA with programmable deaminases.” Nature Reviews Molecular Cell Biology 25, n.º 1, 2024; and Tuncel, Aytug, et al. “CRISPR–Cas applications in agriculture and plant research.” Nature Reviews Molecular Cell Biology, 2025.