Moody's gave a positive review of the potential merger of Honda and Nissan, but former Nissan CEO Carlos Ghosn warned his old employer would face "carnage" if the combination went through.

The Detroit Three are facing an auto industry increasingly affected by the rise of China as demonstrated by the planned merger of Honda and Nissan.

Japanese automakers Nissan and Honda have announced plans for a merger that would catapult them to a top position in an industry that's in flux as it transitions away from its reliance on fossil fuels.