Infrared emission measurements from a high temperature CO2/Ar plasma are presented. An inductively coupled plasma torch was used to produce a CO2/Ar plasma jet at atmospheric pressure. The plasma jet is initially close to Local Thermodynamic Equilibrium conditions at a temperature of 6650 K. This plasma is then passed at high velocity through a water-cooled test-section that forces rapid cooling and recombination. The subsequent thermochemical evolution of the plasma as it traverses the water-cooled tube is studied using Optical Emission Spectroscopy in the infrared region between 4.1 and 5.6 μm. The measured spectra at the exit of the torch and at the exit of the 35-cm test-section are calibrated in absolute intensity and compared with calculations done using the RADIS line-by-line radiation code. The measurements presented here are meant to provide a test case for comparison with kinetic modeling and/or CFD predictions.