As the most significant driver of anthropogenic climate change, atmospheric CO2 needs to be dramatically reduced to avoid catastrophic future scenarios. Hence, chemical systems for removing CO2 from emission streams and even directly from the atmosphere (direct air capture, DAC) are of practical significance. Leading technologies rely on nucleophilic solvents such as alkaline aqueous solutions and amines (e.g., ethanolamine) or on porous sorbents with nucleophilic functionalities, both of which form strong covalent adducts with CO2. To regenerate the stationary phase and release the captured CO2, energy-intensive thermal stripping is the most popular method. Though these systems are becoming increasingly efficient and scalable, there is considerable interest in alternative approaches using materials that cycle between capture and release modes using nonthermal stimuli, including applied electrical potentials, humidity swings, microwave irradiation, and photochemistry. These newer approaches can in principle have advantages in terms of energy efficiency, but the underlying thermodynamic and molecular-design principles are substantially less developed than for thermally driven systems.