02 Jul 2012: African Savannas May Shift
To Forest as CO2 Levels Rise, Study Says

Large areas of African savanna may slowly transform into forest ecosystems by the end of the century as atmospheric levels of carbon dioxide continue to rise, a new study says. While earlier studies have suggested that rising CO2 “fertilization” will not trigger global vegetation shifts, researchers from the Biodiversity and Climate Research Centre and Goethe University Frankfurt say that savanna ecosystems may actually be vulnerable to relatively quick “regime shifts” as plants and trees struggle for ecosystem dominance. According to their findings, savanna trees “were essentially CO2 starved under pre-industrial CO2 concentrations, and… their growth really starts taking off at the CO2 concentrations we are currently experiencing,” said Steven Higgins, lead author of the study published in the journal Nature. According to their projections, small changes in the factors that regulate the ecosystem could potentially trigger a cascade of events that reinforce each other, causing the system to change even more rapidly. The scientists found, however, that different areas of savanna will likely shift at different rates.