An efficient method for extracting the dissolved CO₂ in the oceans would effectively enable the separation of CO₂ from the atmosphere without the need to process large volumes of air, and could provide a key step in the synthesis of renewable, carbon-neutral liquid fuels. While the extraction of CO₂ from seawater has been previously demonstrated, many challenges remain, including slow extraction rates and poor CO₂ selectivity, among others. Here we describe a novel solution to these challenges – efficient CO₂ extraction from seawater using bipolar membrane electrodialysis (BPMED). We characterize the performance of a custom designed and built CO₂-from-seawater prototype, demonstrating the ability to extract 59% of the total dissolved inorganic carbon from seawater as CO₂ gas with an electrochemical energy consumption of 242 kJ mol⁻¹(CO₂).