We evaluate CO₂ profile retrievals from ground-based near-infrared solar absorption spectra after implementing several improvements to the GFIT2 retrieval algorithm. Realistic errors in the a priori temperature profile (~ 2 °C in the lower troposphere) are found to be the leading source of differences between the retrieved and true CO₂ profiles, differences that are larger than typical CO₂ variability. A temperature retrieval or correction is critical to improve CO₂ profile retrieval results.