change of the global atmosphere. you want to look at indicators like the temperature of the deep layer of the atmosphere, say the lowest 30,000 feet of the atmosphere. so what you do is you use satellites to measure that distance between the earth s surface and the height of about 30,000 feet to read temperatures as opposed to reporting from surface stations? how does that differ in terms of the data set? well, because we re looking at the deep layer of the atmosphere, we re not contaminated by the buildings, roads, farms, and so on built at the surface, so we see a true picture of what the global atmosphere is doing. it is warming in the past 30 years, but that rate is quite a bit less than what climate models are indicating, and so that the greenhouse effect as we understand it is overstated i think in the ipcc report. if you talk to michael mann, the man responsible for the hockey stick graph, that shows temperatures fairly steady