CO<sub>2</sub> emission pathways and primary energy supply to 2100

<p><strong>Figure 3.</strong> CO<sub>2</sub> emission pathways and primary energy supply to 2100. Emission pathways for the 2 ° C ceiling target with BECCS (light green) and the 1.5 ° C overshoot target with BECCS (dark green). Below, primary energy supply for the 2 ° C ceiling target with BECCS (middle) and the 1.5 ° C overshoot target with BECCS (bottom). Primary energy supply that has carbon capture applied is shown in lighter colour shades.</p> <p><strong>Abstract</strong></p> <p>In order to meet stringent temperature targets, active removal of CO<sub>2</sub> from the atmosphere may be required in the long run. Such negative emissions can be materialized when well-performing bioenergy systems are combined with carbon capture and storage (BECCS). Here, we develop an integrated global energy system and climate model to evaluate the role of BECCS in reaching ambitious temperature targets. We present emission, concentration and temperature pathways towards 1.5 and 2 ° C targets. Our model results demonstrate that BECCS makes it feasible to reach temperature targets that are otherwise out of reach, provided that a temporary overshoot of the target is accepted. Additionally, stringent temperature targets can be met at considerably lower cost if BECCS is available. However, the economic benefit of BECCS nearly vanishes if an overshoot of the temperature target is not allowed. Finally, the least-cost emission pathway over the next 50 years towards a 1.5 ° C overshoot target with BECCS is almost identical to a pathway leading to a 2 ° C ceiling target.</p>