I can point to many sources advocating humans are the cause of the rising CO2 levels, so I won’t list them here at this time. What I will list is the background noise of sources that point to other causes of climate change, warming, cooling, or whatever the term being used today is.
Back in September 8 2013 The Telegraph reported that the Earth was cooling and not warming. Even in 2011 there was mention of other causes of warming from the European Union Times citing CERN ( European Organization for Nuclear Research) that the Sun causes global warming. Here we have Dr. Tim Ball breaking down the notion that CO2 is a pollutant. Of course CO2 can be dangerous to humans. Anyone that has taken a Biology class knows that plants use CO2 in the Calvin Cycle to aid in photosynthesis and produce oxygen that is needed for human life. So the idea that CO2 is a pollutant is totally crazy when it also aids in sustaining life on Earth.