prevented the conversion of more than a billion of hectares which otherwise would have be converted to arable land, and hence helped to avoid some 590 GtCO2e of emissions (Burney _et al._ , 2010). Land productivity growth in the agricultural sector could play an important role in avoiding GHG emissions also in the future (Havlík _et al._ , 2013). However, the net effect will depend on technology and on the strength of a potential rebound effect (Valin _et al._ , 2013). Overall, climate change mitigation through reducing emissions and increasing the sink in the forestry and other land use sectors appears to be a very cost‐effective measure (Kindermann _et al._ , 2008a), which causes relatively little competition with food production (Havlík _et al._ , 2014), and which is projected to play a crucial role in attaining ambitious mitigation targets (Rose _et al._ , 2012; Kriegler _et al._ , 2014).<sup>1</sup> Energy produced from biomass can under certain circumstances be considered close to carbon neutral because during combustion only carbon previously stored in the biomass is emitted. If such a system were linked to carbon capture and sequestration (CCS), which consists of permanently storing the carbon emitted during combustion, the system would actually provide negative emissions/sink (Obersteiner _et al._ , 2001). Recent studies based on integrated assessment models agree on the need for large scale bioenergy deployment to reach ambitious stabilization targets. Although the feasibility of large scale CCS deployment is still uncertain (Fuss et al. 2014), its role in the stabilization scenarios is crucial.; Kriegler et al. (2014) found that limiting atmospheric GHG concentration to 450 ppm CO2 equivalent by 2100 would be 2.5 times more expensive without CCS technology availability. Lignocellulosic biomass from dedicated plantations would be the major source of biomass, next to residues, and more than 500 million ha of land would be needed to produce the required amounts (Popp _et al._ , 2010). In one respect this represents a challenge to increase agricultural land productivity further, not only to allow for carbon sequestration but also to provide land to satisfy these new demands along with sufficient food production. On the other hand, the demand for energy feedstock will present a new income opportunity in agricultural and forest sectors.

As illustrated in the structure of the IPCC Assessment Reports, analyses of climate change impacts and mitigation have been conducted independently and so far have yet to allow for direct comparison of the relative effects of impacts and mitigation. The present paper tries to fill this gap within a consistent scenario set drawing on the new matrix framework structured along Shared Socio‐economic Pathways (SSPs) and Representative Concentration Pathways (RCPs) (van Vuuren _et al._ , 2014). SSPs provide socioecomic drivers such as population, economic growth, and technological change, for alternative future scenarios attempting to span the space of plausible futures. Here we focus on SSP4 and SSP5, representing unequal fragmented world and fast growing integrated world, respectively. RCPs define the future radiative forcing trajectory and are labelled by the end value by 2100 in W.m<sup>‐2</sup> . They can be used both for impact scenarios assessment where they define the level of climate change, and for mitigation scenarios assessment where they define the mitigation target. We do not attempt to present an exhaustive ensemble of scenarios here but rather focus on the most extreme variants, delineating the span of possible future outcomes. For this, we selected RCP2.6 and RCP8.5, which corresponds to temperature increase below 2°C for the former, compared to pre‐industrial times, and beyond 4°C for the latter. This reflects two contrasted situations of limited and extreme climate change impacts on the one side, and high mitigation efforts and no mitigation efforts on the other side.

> 1 This however presupposes that expansion of wood plantation could take place in the large areas of land not already used as cropland or grassland, overcoming some potential hidden barriers such as labor constraints, infrastructure development needs, and non‐degradation of the available land.

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