The problem you would have with adding a ridge vent or even louvered roof vents is the roof pitch. It's so shallow that I'd be concerned about wind driven rain getting under the front lip and getting into the attic.
An alternative would be to add soffit vents and install a small gable exhaust fan with a louvered cover.
The venting system is left open all year.
Ron
An alternative would be to add soffit vents and install a small gable exhaust fan with a louvered cover.
The venting system is left open all year.
Ron