How does a temperature increase cause an increase in carbon dioxide concentration?
Is that a real question or are you just trying to pull someone's chain?
An increase in temperature causes an increase in the atmospheric CO2 concentration because warm water holds less CO2 than cold water...Try an easy experiment to demonstrate...open two cans of soda...place one in your refrigerator and leave the other on the counter till tomorrow...now have a taste of each..the one in the refrigerator will still be a bit fizzy the one on the counter will be as flat as a flounder...and why you might ask....because warm water can't hold as much CO2 as cold water.
As the oceans warm, they out gas a great deal of CO2..