|| This archive contains data for an ensemble of 24 simulations with the aDGVM for Africa. It includes continental-scale time series for aboveground biomass, water use efficiency (WUE), net primary production and transpiration from 2000 to 2099. In addition, simulated aboveground biomass, tree biomass, net primary production (NPP), transpiration, WUE, and biomes for Africa for the periods 2000-2019 and 2080-2099 at a 0.5° resolution are archived. Simulations were conducted with the aDGVM (Scheiter & Higgins (2009), GCB, doi: 10.1111/j.1365-2486.2008.01838.x).
Abstract: Anthropogenic climate change is expected to impact ecosystem structure, biodiversity and ecosystem services in Africa profoundly. We used the adaptive Dynamic Global Vegetation Model (aDGVM), which was originally developed and tested for Africa, to quantify sources of uncertainties in simulated African potential natural vegetation towards the end of the 21st century. We forced the aDGVM with regionally downscaled high-resolution climate scenarios based on an ensemble of six General Circulation Models (GCMs) under two Representative Concentration Pathways (RCPs 4.5 and 8.5). Our study assessed the direct effects of climate change and elevated CO2 on vegetation change and its plant-physiological drivers.
Total increase of carbon in aboveground biomass in Africa until the end of the century was between 18-43% (RCP4.5) and 37-61% (RCP8.5) and was associated with woody encroachment into grasslands and increased woody cover in savannas. When direct effects of CO2 on plants were omitted, woody encroachment was muted and carbon in aboveground vegetation changed between (–8)-11% (RCP 4.5) and (–22)-(–6)% (RCP8.5). Simulated biome changes lacked consistent large-scale geographical patterns of change across scenarios. In Ethiopia and the Sahara/Sahel transition zone, the biome changes forecast by the aDGVM were consistent across GCMs and RCPs.
Direct effects from elevated CO2 were associated with substantial increases in water use efficiency, primarily driven by photosynthesis enhancement, which may relieve soil moisture limitations to plant productivity. At the ecosystem level, interactions between fire and woody plant demography further promoted woody encroachment.
We conclude that substantial future biome changes due to climate and CO2 changes are likely across Africa. Because of the large uncertainties in future projections, however, adaptation strategies must be highly flexible. Focused research on CO2 effects, and improved model representations of these effects will be necessary to reduce these uncertainties.
||The data stored in this archive were produced in the context of the following publication: C Martens, T Hickler, C Davis-Reddy, F Engelbrecht, SI Higgins, GP von Maltitz, GF Midgley, M Pfeiffer & S Scheiter, Large uncertainties in future biome changes in Africa call for flexible climate adaptation strategies, Global Change Biology, doi:10.1111/gcb.15390 (in press)