Graph showing one degree Fahrenheit rise in the temperature record of the entire earth's surface during the 20th Century.
Graph showing roughly 1000 years of temperature in the northern hemisphere. It is based on combined data from ice layers, corals, trees, etc. The 20th Century's one degree Fahrenheit warming stands out dramatically.
Over a 40 year period, scientist Charles Keeling measured the amount of carbon dioxide (CO2) in the atmosphere. The above "Keeling Curve" shows the increase in total concentrations of CO2 in the atmosphere from 1957-1997. This unbroken record of the carbon dioxide content of the atmosphere shows how it's gone up, in round numbers, from around 315 parts per million to around 370 parts per million on average today. This data is widely accepted by everyone.
Graph showing a 450,000 year record of carbon dioxide (CO2) levels in the earth's atmosphere. This record was compiled from analyzing bubbles of fossilized air trapped in ice cores. The fossilized air shows the levels of carbon dioxide and other gases in the atmosphere throughout this 450,000 period. The last 100-150 years of the 20th Century show a significant rise in CO2.