The U.S. Climate Change Science Program (CCSP), established in 2002 to coordinate climate and global change research conducted in the United States and to support decision-making on climate-related issues, is producing twenty-one synthesis and assessment reports that address its research, observation, and decision-support needs. The first report, produced by the National Oceanic and Atmospheric Administration (NOAA) in coordination with other agencies, focuses on understanding reported differences between independently produced data sets of temperature trends for the surface through the lower stratosphere and comparing these data sets to model simulations. To ensure credibility and quality, NOAA asked the National Research Council to conduct an independent review of the report. The committee concluded that the report Temperature Trends in the Lower Atmosphere: Understanding and Reconciling Differences is a good first draft that covers an appropriate range of issues, but that it could be strengthened in a number of ways.