Africa’s savannahs to become forests by end of the century?
According to research published in Nature, much of Africa’s savannahs could be turning into forests by 2100.
According to research published in Nature, much of Africa’s savannahs could be turning into forests by 2100. According to the research, fertilisation by atmospheric carbon dioxide is likely to induce the change once a threshold level of carbon dioxide is reached.
The reason for the relatively sudden change lies in the sensitivity of the savannah’s grassland and trees to climate and atmospheric changes. Small changes in the amount of atmospheric carbon dioxide can upset the balance between the two plant types and cause a dominance of one type over another.
Many plants do not show a strong response to CO2 fertilisation, but author of the study Steven Higgins says, “Most of these studies were conducted in northern ecosystems or on commercially important species. In fact, only one experimental study has investigated how savannah plants will respond to changing CO2 concentrations and this study showed that savannah 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.”
“The potential for regime shifts in a vegetation formation that covers such vast areas is what is making earth system scientists turn their attention to savannas”, says Higgins. And indeed, there are many practical considerations that this research will create. Certain regions predisposed to forest growth could be targeted as a location to sequester carbon. There is of course, concern for the future of savannahs however; they have unique wildlife which could be threatened with a huge shift in land type.
The move to forested savannahs will not be uniform however. The research suggests that different areas will experience the change at different times, as certain places require more carbon dioxide to trigger the change than others. This may help limit the potential damage, but compared to geological timescales, the change is quick. These fragile regions are also under threat from other man made change, such as over-grazing, plantations and agriculture.