CO2 is a proven greenhouse gas. Adding CO2 to the atmosphere will raise temperature. The complication being that the system has so many factors that drive climate, so increase in temperature is not linear....CO2 is absorbed in oceans, taken up by plant growth, etc, etc, including that the sun is nearing the low point of its current sunspot cycle, which is associated with periods of cooling. Nevertheless, CO2 uptake has its limits and solar activity will increase with the next up cycle, so what we have now is just a period of grace that can allow us to take action that can ameliorate the inevitable shift in climate.
