Don’t forget: CO2 is plant food
Climate change, this global warming thing, it’s going to mean that the tropical forests frazzle up and then we all die, right? It will mean the death of the “lungs of the planet” – such as the miles upon miles of Amazon jungle – which turn CO2 into the O2 that we inhale. It’s titsup for humanity, basically. Except, according to one new paper in Nature, that’s not the way it will work. CO2 is indeed plant food and more plant food means more plants, more forests and thus we’re all saved: or perhaps not quite as screwed as some seem to think at least.
The point is this:
Experimental studies have generally shown that plants do not show a large response to CO2 fertilisation. “However, most of these studies were conducted in northern ecosystems or on commercially important species” explains Steven Higgins, lead author of the study from the Biodiodversity and Climate Reseach Centre and Goethe-University. “In fact, only one experimental study has investigated how savanna plants will respond to changing CO2 concentrations and this study showed that savanna trees were essentially CO2-starved under pre-industrial CO2 concentrations, and that their growth really starts taking off at the CO2 concentrations we are currently experiencing.“
Purists will cavil at this description, but grasslands and forests compete with each other. Forest cover kills off the grass and thus grasslands only thrive where trees don’t. Savannas are, to a useful level of truth, the front line where the battle is taking place. As the paper points out, the trees on these savannas are finding their growth limited by the amount of food they can get: the CO2 from the atmosphere. As we burn more fossils that will go up, the trees will get more food and forests will advance across those grasslands.