The global sensitivity of atmospheric retrieval from the AIRS observations was investigated to quantify the largest error source at the IR wavelengths for global and regional carbon-cycle studies. To fully resolve the line features and obtain maximum radiance sensitivity, the results were calculated using the LBLRTM and presented at spectral resolution , which is the typical linewidth of at standard temperature and pressure. The results show that temperature, , and water vapor are important factors, which have great influences on the sensitivity of atmospheric retrieval from the AIRS observations. Specifically, the water vapor is the most important factor in the tropics, whereas the temperature represents major interference for midlatitude and subarctic regions. Moreover, the maximum error caused by temperature, water vapor, and data in retrieval occurs for midlatitude regions under summer conditions. The findings are in good agreement with those from the ground-based validation of the AIRS products. Therefore, precise measurements of the water vapor profile, access to data, and good knowledge of the atmospheric temperature profile are important to reduce errors, especially in the retrieval for midlatitude regions.