Sean...
The original idea about "greenhouse" gases dates back to 1824...and was confirmed in the late 1800's...so this is not a new theory. The computer models I have seen say "here is the situation today...if the rate of increase continues at its current pace, this is what we will have X number of years down the road...computer models are tested against the past...does the model accurately predict what has happened? The answer is yes...
Neil...
I understand fully....what you fail to understand is this is meteorological data...surface temperature....measuring climate change does not rely SOLELY on meteorological data that shows the up and downs on a daily basis of temperature.....never the less, this data is adjusted to take into consideration the "urban heat island effect"....
They use weather balloons, satellites...etc, to measure surface temps....they also look at ocean water temps, ice core samples, they measure what's going on in the atmosphere, ice sheet thickness, sea levels, etc. etc....