A method and apparatus are disclosed for controlling a concentration of carbon dioxide in a gaseous atmosphere within a closed environment of a refrigerated transport container to maintain the concentration of carbon dioxide therein at a desired level. A carbon dioxide scrubber apparatus operates alternately in an adsorption mode and a regeneration mode. When a perishable produce is stowed in the closed environment, for example in a cargo box of a refrigerated transport container, the concentration of carbon dioxide may be maintain at a desired level to retard ripening of the perishable produce.