A greenhouse gas, carbon dioxide traps solar heat in Earth’s atmosphere. The gas is known as the biggest contributor to global warming of the planet.
That phrase says exactly what I claimed: They are claiming CO2 (specifically implying man-released CO2) is the biggest greenhouse gas. CO2 is NEITHER the biggest GHG, nor is man-released CO2 the biggest GHG.
You're twisting their words and trying to claim that "Biggest Greenhouse Gas" = "Biggest Contributor to Global Warming," while I'm sure you realize they don't mean the same thing.
Obviously, "Global Temperature Increase" would be a better term than "Global Warming," so the differential is emphasized, but the definitions are accepted. Even though I disagree with the IPCC on whether or not indirect effects should be included in the term "Radiative Forcing," their definition is standard and it's silly to just argue the definition as if that means making a point about the real world. Define things as you want, but they didn't claim that CO2 has a greater greenhouse effect than water vapor.