CO2-switchable viscoelastic surfactant solutions have gained much attention over the last decade; however, large-scale application and the impact of temperature and pressure on such soft colloidal materials have not been explored yet. Here in this work, the impact of environmental parameters including shear rate, pressure, temperature, and salinity on CO2-thickening behavior of aqueous dispersion of N-erucamidopropyl-N,N-dimethylamine (UC22AMPM) was assessed rheologically. Preliminary immiscible water-alternating-CO2 (CO2-WAG) flooding tests with and without UC22AMPM were conducted to highlight the potential of CO2-switchable surfactants in the process of improved oil recovery. The results demonstrated that the dispersion can be viscosified by CO2 15 times higher at 60 °C and 5 MPa, and such thickening power can be switched “on” and “off” upon bubbling and removal of CO2. A universal double-plateau viscosity profile was found as a function of CO2 bubbling time irrespective environmental condition, but the higher the shear rate or the pressure, the shorter the time is needed to reach the plateau viscosity; the higher the temperature, the longer the time is needed to get to the second plateau viscosity. UC22AMPM is first protonated into a long-chain cationic surfactant to form wormlike micellar solution, then the first viscosity plateau; expansion of the viscoelastic solution with CO2 attributes to the second viscosity plateau. Under the simulated oil reservoir of Daqing oilfield, immiscible CO2-WAG flood alone produced an additional 10.5% oil over the initial waterflood recovery, while the addition of 2.1 wt% UC22AMPM in the water slug could recover incremental 5.1% oil relative to pure CO2-WAG. These unique features suggest that coupling injection of CO2 and UC22AMPM dispersion holds great promise for recovering oil during the immiscible CO2-WAG process.