For a few months I've been reading the blog 'Watts up with that?' Anthony Watts comments on many things, but mostly focuses on collecting evidence of bad scientific technique in the measurement of climate conditions. Anthony is a global warming skeptic - and so am I.
Today Anthony continued his ongoing series, 'How not to measure temperature'. This is part 75 of that series. Anthony and the people he works with have uncovered STAGGERING numbers of weather stations which should be considered invalid due to various effects.
Check out the links at the top for a selection of worst offenders. My favorite is the one next to the barbecue grill.
Anthony also runs an effort to physically survey all the weather history stations in the country: http://www.surfacestations.org/. One of the worst offenders listed there is right here in Oregon: a weather station 10 feet from an air conditioner in forest grove.
Just look at these sites and see if you start to see a different correlation than CO2 to this supposed temperature increase. Maybe someone should make a graph of 'global warming' versus the cost of window-mounted air conditioners.