The period known as the Holocene Maximum is a good example of how the Earth's warming isn't a function of man-made pollution. The Holocene Maximum began 7,500 years ago and is named because it was the hottest period in human history. The interesting thing is this period occurred approximately 7500 to 4000 years B.P. (before present)-- long before humans invented the Ford Explorer.
Now, can we agree that there are many factors at play here that don't lend themselves to a quick diagnosis of U.S. = big polluter = huge amounts of CO2 = global warming = floods, hurricanes, droughts, planet-wide environmental catastrophe?