It is not actually true that there is a consensus about CO2 being a problem. What are close to consensus opinions are that CO2 levels are rising and that we're in a long term warming trend. There is actually a lot of disagreement about the degree to which CO2 is contributing to warming, the degree to which humans are driving the increase in CO2, and whether or not a warmer world is something to be avoided.

It is also widely acknowledged that CO2 is causing a massive increase in global biomass.