Evidence that CO2 is Cause

-CO2-Tempcarbon dioxide vs global temperature graph

 
Local and global weather has always fluctuated and always will, so global warming cannot be expected to be a smooth process. But what can be seen above is that half of all man-made CO2 has been put into the air since 1975, and that matches the one-degree F global temperature increase since 1975 rather well.

This is not proof of that the CO2 caused the warming. But, if CO2 did not cause it, we have a somewhat unusual coincidence. As seen on the temperature page this thirty-year temperature increase is unusual. There was only one temperature swing of this size in the oldest thermometer record which dates back 350 years, and it was a down swing. Upswings of this magnitude would seem to happen only about once in 700 years, and this one happened right in step with human CO2 production. 

Caution:  The match of the CO2 and temperature graph above is somewhat deceptive. Since one is temperature and one is CO2 they cannot be graphed on the same axis, so the two axes have been adjusted to align the two. However this process does not change the fact that temperature rose faster from 1975 to now than from 1880 to 1975, and so did CO2. It also cannot change the fact the temperature has been highest recently and so has CO2.

The slight downward trend in temperature from about 1945 until about 1975 is due to the increase in Sulfate Aerosols (SO4), largely produced by burning coal that contains sulfur. These cool the earth, and their increase during these years largely canceled the increase in CO2 during the same period.