The co2 level is during winter in the northern hemisphere compared to levels in the summer. the same higher lower

I believe that the level of CO2 level is higher during winter in the northern hemisphere compared to levels in the summer. There's more carbon dioxide in the winter and a bit less in the summer. That's the collective breathing of all the plants in the Northern Hemisphere. Plants are accumulating carbon in the spring and summer when they are active, and they are releasing carbon back to the air in the fall and winter. 

Ireally dont know sorry