Biomass plantations used for fossil-fuel substitution are more efficient for climate-change mitigation than afforestation
Using biomass for fossil-fuel substitution is an economically viable method of carbon dioxide removal. In simulations with the Max Planck Institute Earth System Model, we covered the abandoned agricultural areas of RCP4.5 with either forests or herbaceous biomass plantations and assessed their effects on the climate under RCP8.5 emissions. Our scenario simulated an expansion of herbaceous biomass plantations to 5.6 million square kilometers. Global yields over the 95 years simulated amount to 255-330 PgC. When used for fossil-fuel substitution, they reduce carbon dioxide concentrations by 150-170 ppm and temperatures by 0.8-1.0°C compared to RCP8.5 while afforestation reduces these values by 85 ppm and 0.4°C respectively. Forests respond to CO2-fertilization more strongly than do herbaceous biomass plantations, therefore a replacement reduces the area’s sink capacity, nevertheless, with fossil-fuel substitution biomass plantations become more effective than forests within 30 years in most areas of the globe assuming a 100% fossil-fuel substitution level. They remain effective in many areas even when current technological limits of 30-70% substitution levels are accounted for. Overall, we conclude that herbaceous biomass plantations reduce CO2-concentrations more than the regrowth of forests when used for fossil-fuel substitution.
Dorothea Mayer is serving as a Post-Doc at Max-Planck-Institute for Meteorology (MPI) in Hamburg, Germany since 2017. From 2013 to 2017 she completed her PhD in Earth System Science at the MPI in the International Max-Planck Research School on Earth System Modelling (IMPRS-ESM), a cooperation between the MPI and the University of Hamburg. She received her Master degree in Forest Ecology and Management and her Bachelor diploma in Biology from Albert-Ludwigs University in Freiburg, Germany.