Articles | Volume 8, issue 3
Research article
05 Sep 2017
Research article |  | 05 Sep 2017

Impacts of climate mitigation strategies in the energy sector on global land use and carbon balance

Kerstin Engström, Mats Lindeskog, Stefan Olin, John Hassler, and Benjamin Smith

Abstract. Reducing greenhouse gas emissions to limit damage to the global economy climate-change-induced and secure the livelihoods of future generations requires ambitious mitigation strategies. The introduction of a global carbon tax on fossil fuels is tested here as a mitigation strategy to reduce atmospheric CO2 concentrations and radiative forcing. Taxation of fossil fuels potentially leads to changed composition of energy sources, including a larger relative contribution from bioenergy. Further, the introduction of a mitigation strategy reduces climate-change-induced damage to the global economy, and thus can indirectly affect consumption patterns and investments in agricultural technologies and yield enhancement. Here we assess the implications of changes in bioenergy demand as well as the indirectly caused changes in consumption and crop yields for global and national cropland area and terrestrial biosphere carbon balance. We apply a novel integrated assessment modelling framework, combining three previously published models (a climate–economy model, a socio-economic land use model and an ecosystem model). We develop reference and mitigation scenarios based on the narratives and key elements of the shared socio-economic pathways (SSPs). Taking emissions from the land use sector into account, we find that the introduction of a global carbon tax on the fossil fuel sector is an effective mitigation strategy only for scenarios with low population development and strong sustainability criteria (SSP1 Taking the green road). For scenarios with high population growth, low technological development and bioenergy production the high demand for cropland causes the terrestrial biosphere to switch from being a carbon sink to a source by the end of the 21st century.

Short summary
Applying a global carbon tax on fossil was shown to lead to increased bioenergy production in four out of five scenarios. Increased bioenergy production led to global cropland changes that were up to 50 % larger by 2100 compared to the reference case (without global carbon tax). For scenarios with strong cropland expansion due to high population growth coupled with low technological change or bioenergy production, the biosphere was simulated to switch from a carbon sink into a carbon source.
Final-revised paper