I saw a video clip, wherein an NOAA official indicated that it was his belief that Global Warming was indeed happening. He indicated that the human factor may be accellerating the natural cycle. I believe that this is the most likely scenario, but agree that we just do not know enough to peg the cause or even if a warming cycle is happening. We are so arrogant. Bye the way, I love the weather data collection work you are doing. The purpose of most of these stations was to collect weather specific to an airport for pilot forecasts and terminal forecasts. I wonder if historical data is available for the weather balloon data that has been collected over the decades that would not be as affected by the urban bubbles of heat you illustrate . . .