Thicker-leaved plants may thrive due to climate change, which may help temper climate change’s effects

Work by a team of scientists including Abigail Swann, who serves on the PCC executive board, and Marlies Kovenock, a former PhD student of Swann, looked into how tropical forests may be adapting to changing climate and how these adaptations have the potential to mitigate the effects of climate change. Tropical forests are currently responsible for absorbing a large amount of carbon dioxide from the atmosphere, but information on how plants and ecosystems may respond to the rising CO2 levels is not abundant, making this research critically important.

The team’s results show that increases in atmospheric carbon levels may drive changes in plant leaf morphology, leading to plants with these adaptations being able to outcompete other species. One example of such an adaptation is the ability to grow thicker leaves in environments with high levels of atmospheric carbon. Although it is not explicitly clear why plants begin to grow thicker leaves in high carbon environments, the team’s research proposes that thick leaves will help certain species become better competitors through maximizing photosynthesis.

The availability of CO2 in the atmosphere is theoretically advantageous for plants, making it easier for photosynthesis to occur. However, even if carbon is abundant in the atmosphere, without enough nitrogen, plants do not photosynthesize well. This is where having thick leaves helps: thicker leaves can potentially help concentrate nitrogen to ensure photosynthesis rates per area of leaf remain high in carbon-rich environments. In fact, simulations run by Kovenock and Swann’s team for Barro Colorado Island in Panama found that trees with thickened leaves were able to absorb carbon and produce water vapor, enabling them to grow and regulate temperature, much more efficiently than trees programmed to have more carbon relative to nitrogen in their leaves. Thus, thicker-leaved trees were able to outcompete other species while also absorbing more CO2 through increased rates of photosynthesis.

This work presents a fascinating revelation: the shifting of which plant species with which traits are growing in these tropical forests is occurring due to climate change, and those developments have the potential to help mitigate the consequences of increasing atmospheric CO2. The way plants respond to climate change is still largely unexplored, but the continuation of this work will surely be instrumental in developing our understanding of this effect, and how it will influence our planet’s future.

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