There are other problems than just climate change associated with increasing levels of CO2.
Although increased plant growth has been touted as a benefit of increased CO2, it is not a benefit. Photosynthesis does increase increasing sugar production which is the building block for cellulose allowing for more growth. But other nutrients are not taken up any faster. The result is nutrient dilution. As the volume increases the concentration of nutrients goes down. This is not a good thing for food production. Our soils are already largely depleted of trace minerals and their lack in soil has been a recognized problem since the 1930’s. Nutrient dilution from CO2 just adds another layer to the problem.
Ocean acidification is simply caused by the fact that CO2 when dissolved forms a mild acid. This has been widely reported for some time. It plays a role in coral reef bleaching along with the rising temperatures.
But probably the worst effect is on our bodies. Try holding your breath. Do it long enough and your body forces you to breath. Why? How does your body know it needs to breath? The buildup of carbon dioxide in your blood is what makes you feel the need to breath. It is not the need for oxygen. We think of carbon dioxide as nontoxic, but that is false. Carbon dioxide is very toxic to your tissues at higher levels. Chemicals will disperse through diffusion and move from areas of higher concentration to areas of lower concentration. But you blood level of CO2 can never be any lower than the level in the atmosphere. We will reach a point, if we haven’t already, when people become less mentally acute. As levels continue to rise, we are all one big laboratory experiment. As we increasingly need to all become more reasonable to solve our environmental problems, we just might all have brain fog from excess levels of CO2.