To simplify the analysis, you decided to not look at the engine, the transmission, the gearbox, the drive shaft, the differential, the axle, and the wheel, to focus attention on one portion of the thread of one bolt of one nut on the right rear wheel.
Figure 1 is a systems diagram of the atmosphere and atmospheric processes.
It appears complex, but is, in reality, a simple representation. The people who created the Intergovernmental Panel on Climate Change (IPCC) decided this system, analogous to your car was faltering. Through their definition of climate change as only those changes caused by humans, they narrowed the search to human CO2. In the diagram, it is one thread on one bolt in the section labelled "Atmospheric composition." That section includes all the gases of the atmosphere and the billions of tonnes of particulates. These gases and particles affect the incoming solar radiation and outgoing long-wave heat energy. They also vary over time, but we have virtually no idea of quantities or the variability. Of all the gases in the composition, the so-called greenhouse gases (GHG) comprise approximately 4 percent. And of that 4 percent total, carbon dioxide (CO2) is 4 percent, and human CO2 is approximately 3.4 percent. It is one thread on one bolt of the complex system. The actual amount of human-produced CO2 added to the system is an estimate produced by the IPCC. It is, like all other numbers used, a barely educated guess presented with the authority that it is accurate and real.