Here, we report a distinct mechanism for harnessing CO2-responsiveness through enhancing CO2 capture ability. The finding is demonstrated on the microgels that are composed of oligo(ethylene glycol) and sulfonate moieties. Laser light scattering studies on dilute aqueous dispersion of these microgels indicated a low CO2-responsivity, which can be significantly enhanced by adding NaCl and other salts. This salt-enhanced CO2-responsiveness of microgels can be elucidated by the antipolyelectrolyte behavior and its superposition of forming cross-links physically with CO2 as an intermediate. Further results of the filtration experiments on microgel translocation through pores suggest the feasibility of the explanation. The finding is also supported by the CO2 capture-release experiments on the dispersion, which can reversibly absorb and desorb CO2.