There has been a 1 or 2 C rise in ocean temperatures over the last century, mostly as the result of coming out of the Little Ice Age. That would cause a 5 to 10 ppm rise in CO2. Instead we have seen a 110 ppm rise in CO2. There is clearly an effect from rising ocean temperatures but there is a bigger effect from manmade emissions.
The oceans no longer emit CO2 as they warm, they now absorb some of our extra CO2 although they absorb less of our extra than they would if they were not warming.