Mechanical engineering. Same difference.
Actually, you are exactly right. Thermodynamics is required course for both degrees (I know, I suffered through it.) If you took (and passed) thermodynamics you would understand that CO2 is not a greenhouse gas. CO2 has the same heat coefficient as H2O (at the same temp and pressure.) This means that it reflects, absorbs and lets through the same amount of sunlight as water vapor (clouds). Does it get warmer or cooler when a cloud passes overhead? Basic thermodynamics. CO2 is a plant food.
I'm thinking he either forgot basic thermodynamics or failed the class.