http://en.wikipedia.org/wiki/Earth's_atmosphere (Pie chart a little bit down the page.)
Let's say, just for argument, that the amount of CO2 in the atmosphere doubles. Then it makes up 0.07% of the earth's atmospheric gases.
This is not going to kill us.
"Carbon emissions for U.S. territories range from 9 to 12 million metric tons per year." http://www.eia.doe.gov/oiaf/1605/gg99rpt/appendix
One metric ton is 1000 kg.
"Volcanic activity now releases about 130 to 230 teragrams (145 million to 255 million short tons) of carbon dioxide each year." http://en.wikipedia.org/wiki/Volcano
One short ton is 2000 kg.
Let us compare. US activity gives off 18-24 million short tons, volcanic activity 145-255 million short tons, of CO2 each year.
How much can we affect climate change if our entire CO2 emission is 1 percent of that of a single natural source of CO2?
It's almost enough to make you not want to moderate, sifting through the enormous amounts of absolute shit that people spam