This paper investigates alternative pathways for the global economy's transition from a fossil-fueled to a low-emission sector, modifying a climate change and economy integrated assessment model. Three transition pathways (Linear, Delayed, and Fast) are analyzed. Results show that capital formation, accumulation, and transfers, facilitated by full R&D investment in the green sector's productivity, are crucial. The Delayed pathway relies on higher green capital investment and increased green capital productivity via R&D, while the Fast pathway needs substantial capital transfers from the brown sector and high abatement efforts.