Short-term action is key for gigaton-scale Direct Air Capture by 2050.

Direct Air Capture (DAC) is widely considered essential for achieving net-zero and net-negative emissions, yet its potential to scale to climate-relevant levels remains uncertain. Here we show that the future deployment of DAC depends primarily on early capacity expansion and growth dynamics rather than on long-term demand targets alone. Using a probabilistic technology diffusion model informed by historical analog technologies and uncertain future demand, we explore a wide range of possible global DAC deployment pathways to 2050. We find that if DAC follows growth trajectories similar to ammonia synthesis technologies and liquefied natural gas, deployment is likely to remain at the megaton scale by mid-century. However, gigaton-scale deployment becomes plausible under rapid growth and strong early policy support. Our results identify short-term capacity expansion as the most effective lever for accelerating DAC deployment and highlight the critical importance of timely policy action to avoid overreliance on future large-scale carbon removal.