Pursuing an all-of-the-above portfolio of carbon removal pathways could enable considerably more cumulative carbon removal through 2050 than any other scenario. Natural carbon capture pathways alone are incapable of reaching a 2 GtCO2 per year target due to the estimated total carbon removal need for this century exceeding what natural carbon capture can provide. A technology-only or direct-air-capture-only portfolio could reach this level of deployment by 2050 (or shortly thereafter), but would yield considerably less cumulative removal over that period due to the time required to develop, deploy and scale up emerging technologies.
An all-of-the-above portfolio is also the most risk-averse strategy because it creates the most options for achieving the 2 Gt target by 2050, should any single pathway fail to realize its expected potential. Assuming direct air capture remains the highest-cost pathway, the all-of-the-above portfolio is also the least-cost scenario. Because this scenario still requires aggressive development of direct air capture technology, this scenario positions direct air capture to scale beyond 2050.