Climate explained: why plants don’t simply grow faster with more carbon dioxide in air

Rising atmospheric carbon dioxide (CO₂) is warming our climate, but it also affects plants directly. 

Fast-growing plantation trees store less carbon per surface area
 than old, undisturbed forests that may show little growth.

A tree planted in the 1850s will have seen its diet (in terms of atmospheric carbon dioxide) double from its early days to the middle of our century. More CO₂ generally leads to higher rates of photosynthesis and less water consumption in plants. So, at first sight, it seems that CO₂ can only be beneficial for our plants.

But things are a lot more complex than that. Higher levels of photosynthesis don’t necessarily lead to more biomass production, let alone to more carbon dioxide sequestration. At night, plants release CO₂ just like animals or humans, and if those respiration rates increase simultaneously, the turnover of carbon increases, but the carbon stock doesn’t. You can think of this like a bank account – if you earn more but also spend more, you’re not becoming any richer.

Read the story from The Conversation by an Associate Professor, from Auckland University of Technology, Sebastian Leuzinger -  “Climate explained: why plants don’t simply grow faster with more carbon dioxide in air.”