The escalating climate crisis necessitates the urgent identification and enhancement of all potential carbon sinks. While mature terrestrial ecosystems play a pivotal role in carbon sequestration, their capacity tends to be saturated or near to. Emerging weakly-weathered regions, such as glacier retreat zones, landslide scars, and abandoned mines, constitute an expanding yet underexploited frontier for carbon sequestration. The development of productive ecosystems on these nascent substrates is strongly constrained by nutrient scarcity, particularly for nitrogen and phosphorus. We argue that harnessing natural biological processes, especially biological nitrogen fixation and microbial phosphorus solubilization, is a key to overcoming this barrier. Evidence from soil chronosequences, exemplified by the Hailuogou Glacier forefield, shows how these processes drive rapid biomass accumulation and the emergence of functional carbon sinks. We propose that targeted management to enhance the microbial and symbiotic pathways can accelerate ecosystem assembly on nascent substrates, offering a significant contribution to global carbon neutrality. However, enhanced nitrogen and phosphorus availability may promote soil respiration in weakly-weathered regions while increasing productivity. Therefore, further attention should be paid to the carbon balance. Notably, the sustainable supply of mineral nutrients such as phosphorus is another issue that needs further research.