Carbon Dioxide is really good stuff, we don't have enough of it. It is food for plants, which by photosynthesis release from it (and from water) the Oxygen we breathe.
The main effect of fossil fuel use has been to green the planet, feeding us and preventing famine. The effect is huge. NASA say "increase in leaves on plants and trees equivalent in area to two times the continental United States."
https://www.nasa.gov/feature/goddard...greening-earth
It is also worth noting that there is no scientific proof whatsoever that CO2 acts as a "greenhouse gas" in the earth's atmosphere. There is no correlation between CO2 levels and planetary temperatures.
The Medieval Warming Period was some 1.5C warmer than the current one and the Roman Warming Period as much as 4C warmer, yet their CO2 levels were lower.
However there is a correlation between Milankovitch Cycles and global temperature. These are caused by scientifically proven variation to the Earth's orbit due to the gravitational pull of the planets.