All the CO2 absorbed into the water systems of the world does not come out due to the formation of insoluble metal carbonates. Even more is removed by microscopic plant life. This may be one reason why the CO2 measured is actually lower than models predict.
It is true that as the temperature increases, less CO2 is absorbed by the water, but as the temperature increases, more water vapor is put into the atmosphere.
Water vapor is much, much, much better at warming the atmosphere than CO2. Global average for CO2 in the atmosphere is 400 ppm. The global average for water vapor is > 2,000 ppm. If these numbers are true, there is no way that CO2 generated by man could be a significant contributor to global warming.