According to http://usinfo.state.gov's Washington file, "The [180 page] report, Temperature Trends in the Lower Atmosphere: Steps for Understanding and Reconciling Differences, ...says that data show clear evidence of human influences on the climate system due to changes in greenhouse gases, aerosols and stratospheric ozone."

 

The report tackles some of the long-standing difficulties that have impeded understanding of changes in atmospheric temperatures and the basic causes of these changes.

 

Its Chief Editor, Dr. Thomas Karl, director of National Oceanic and Atmospheric Administration's (NOAA) National Climatic Data Center said, “This synthesis and assessment report exposes the remaining differences among different observing systems and data sets related to recent changes in tropospheric and stratospheric temperature. Discrepancies between the data sets and the models have been reduced and our understanding of observed climate changes and their causes have increased.  The evidence continues to support a substantial human impact on global temperature increases. This should constitute a valuable source of information to policymakers.”

 

According to the NOAA errors that have been identified in the satellite data and other temperature observations have been corrected. These and other analyses have increased confidence in the understanding of observed climatic changes and their causes. The published report also states that research to detect climate change and attribute its causes using patterns of observed temperature change in space and time shows clear evidence of human influences on the climate system due to changes in greenhouse gases, aerosols, and stratospheric ozone. Also, the observed patterns of change over the past 50 years cannot be explained by natural processes alone, nor by the effects of short-lived atmospheric constituents such as aerosols and tropospheric ozone alone.

 

And the NOAA goes on to say, "One issue does remain however, and that is related to the rates of warming in the tropics. Here, models and theory predict an amplification of surface warming higher in the atmosphere. However, this greater warming aloft is not evident in three of the five observational data sets used in the report.  Whether this is a result of uncertainties in the observed data, flaws in climate models, or a combination of these is not yet known.  Using the evidence available, the author team favors the first explanation."

 

The overall conclusion by the report's authors?

 

"The observed patterns of change over the past 50 years cannot be explained by natural processes alone".

 

The letter to the US Congress which accompanied the report contains the following final paragraph and signatures.