As atmospheric CO2 levels continue to rise and emerging geopolitical issues threaten global energy supplies, novel methods of forming fuels sustainably and without geographic restrictions are required for a secure energy supply in a future net zero carbon economy. The utilization of low concentrations of CO2 holds considerable promise given its potential to both produce renewable fuels and prevent the release of CO2 into the atmosphere through the conversion of flue gases, or even directly remove excess CO2 from the atmosphere. However, electrochemical CO2 reduction (CO2R) has so far focused on the utilization of saturated (100%) CO2 streams as state-of-the-art catalysts perform poorly under low CO2 concentrations due to the low availability of dissolved CO2 (12 µM at atmospheric CO2 concentrations, 420 ppm). As most synthetic CO2R catalysts exhibit first order kinetics, their activity decreases proportionally with CO2 concentration, meaning their activity is significantly reduced even at flue gas concentrations. Synthetic catalysts also commonly suffer from side-reactions (in particular hydrogen evolution) that are only marginally affected by CO2 concentration, thereby decreasing the proportion of energy going towards forming the desired carbon products (i.e., the faradaic efficiency, FE) when utilizing CO2 from low concentration sources. While there have been some reports of direct CO2 reduction at concentrations down to 1%, the low affinity of these systems limit their applicability for atmospheric CO2 and are often accompanied by the production of significant side products. The limitations of current CO2R systems therefore require emerging carbon capture technologies to produce concentrated CO2 gas streams in order to achieve acceptable performances. However, CO2 concentration from atmosphere for this stepwise process must incur substantial energy and cost penalties (projected to be 9 GJ ton -1 and $94-232 ton -1 ) to enable efficient carbon capture and utilization from dilute gas streams. This must also be addressed alongside common challenges in capture streams with impurities such as O2, NOx and SOx. Nature does not require such compromises and has evolved efficient approaches to utilize atmospheric CO2 directly to make complex products (e.g. sugars) using the carboxysomea membraneless organelle used to efficiently fix CO2 within cyanobacteria. The rate limiting step for cyanobacterial carbon fixation is catalyzed by ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO), which displays a low catalytic rate under reduced CO2 conditions and competing utilization of O2. The carboxysome provides a microenvironment that overcomes the limitations of RuBisCO by recruiting carbonic anhydrase (CA) and encapsulating both enzymes within the organelle's protein shell (Figure ). CA catalyzes the conversion of HCO3 -to CO2 within the carboxysome, accelerating the kinetically slow interconversion of HCO3 -and CO2 (eq. 1) from an uncatalyzed rate of 0.05 s -1 to rates up to 1•10 6 s -1 . The fast interconversion of HCO3 -and CO2 provides a higher effective concentration of carbon for fixation as all dissolved inorganic carbon species can now be utilized to overcome the concentration limits imposed by using CO2 alone as the carbon source for RuBisCO.