without negative emissions from bioenergy AND CO2 capture and storage

Abstract Combining bioenergy and carbon dioxide (CO 2 ) capture and storage (CCS)technologies (BECCS) has the potential to remove CO 2 from the atmosphere whileproducing useful energy. BECCS has played a central role in scenarios that reduceclimate forcing to low levels such as 2.6 Wm −2 . In this paper we consider whetherBECCS is essential to limiting radiative forcing (RF) to 2.6 Wm −2 by 2100 using theGlobal Change Assessment Model, a closely coupled model of biogeophysical andhuman Earth systems. We show that BECCS can potentially reduce the cost oflimiting RF to 2.6 Wm −2 by 2100 but that a variety of technology combinations thatdo not include BECCS can also achieve this goal, under appropriate emissionsmitigation policies. We note that with appropriate supporting land-use policies terres-trial sequestration could deliver carbon storage ranging from 200 to 700 PgCO 2 -equiavalent over the 21st century. We explore substantial delays in participation bysome geopolitical regions. We find that the value of BECCS is substantially higherunder delay and that delay results in higher transient RF and climate change.However, when major regions postponed mitigation indefinitely, it was impossible toreturn RF to 2.6 Wm