Balancing the Carbon Equation: Why Direct Air Capture and Ocean Alkalinity Enhancement Must Work Together for Climate Stability?

Direct Air Capture (DAC) and Ocean Alkalinity Enhancement (OAE) are two of the most discussed ways to remove carbon dioxide from the atmosphere, each with distinctive mechanisms, strengths, and drawbacks. DAC captures CO₂ directly from ambient air via chemical or physical sorbents followed by storage or utilization, while OAE works by bolstering the ocean’s natural capacity to absorb CO₂ through increasing dissolved alkalinity, shifting inorganic carbon equilibria, and buffering pH changes. In this opinion piece I argue that neither method is sufficient alone but that together they could form a more resilient, scalable negative emissions portfolio. DAC offers precision and controllability; OAE leverages vast ocean sinks and offers co-benefits for ocean acidification, but faces challenges around environmental risks, monitoring, permanence, and scale. I call for an integrated strategy: rigorous foundational science, transparent accounting, regulatory guardrails, and public engagement. Such an approach must prioritize emissions reduction first, then deploy DAC and OAE where they are most effective, ethical, and socially acceptable.