From the Land of Fruits and Nuts....

[ViPER1313]

The whole earth heats / cools on a natural basis thing is true, but the past 100 years have been the hottest in the past 100k (scientists can use ice core data from the poles to get a pretty accurate picture on the temperatures of the earth ranging back several hundred thousand years.) The amount of CO2 in the atmosphere has doubled in the past 50 or so. Not many people actually debate that the CO2 in the atmosphere is responsible for the increase in global temperatures over the past 100 years. What people do debate is how 2x or 3x the amount of CO2 present in the atmosphere today will affect global climates 100 years down the road.