one poster said this- I will ignore computer programs that collect and store the raw data. what happens to the raw data? I especially want the pro-CAGW crowd here to actually think about this. is there a difference between data collected 15 years ago and 150 years ago? yes, of course, older data was collected with different equipment and fewer times a day. can that be corrected for? yes, to a certain extent. typically by computer models that estimate the deviation for such things as time of observation bias, etc. there are also computer models that supposedly correct for undocumented station location changes, etc. I could go on but I dont want to get bogged down here. How are averages calculated for states, countries and the globe? grids are defined and representative sites are included via, you guessed it, climate models. when there are few or no stations in a grid how do they determine the values? I bet you are catching on by now. what I really want to ask the pro-AGWers and climate science apologists is; do you think that the temperature values of existing readings have gone up, down or remained the same in the last 15 years? the last 5 years? in the last year? is anyone brave enough to answer that question?